JPH01283564A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide the durability and mechanical durability in terms of electrophotographic characteristics in combination to the electrophotographic body having a photosensitive layer on a conductive base and to obviate the generation of a pause memory by incorporating >=1 kinds of lubricant powders, >=1 kinds of specific charge transfer materials and specific compd. into the layer furthest from the substrate of the above-mentioned photosensitive body. CONSTITUTION:This electrophotographic sensitive body has the photosensitive layer on the conductive substrate and the layer furthest from the substrate of said body contains >=1 kinds of the lubricant powders, >=1 kinds of the charge transfer materials having >=0.6V oxidation potential and the compd. expressed by formula I. The mechanical characteristics such as slipperiness, wear resistance and release property of deposits on the surface layer are effectively improved by the addition of the lubricant powders and the durability to corona products is improved by the use of the charge transfer materials having the high oxidation potential. Further, the pause memory of the photosensitive body is prevented by the compd. of formula.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a highly sensitive and durable product that is widely used in electrophotographic application fields such as electrophotographic copying machines, laser beam printers, CRT printers, and electrophotographic plate making systems. 1''A to an excellent electrophotographic photoreceptor. [Prior art] In recent years, various organic photoconductive materials have been developed as photoconductive materials for electrophotographic photoreceptors, and these organic photoconductive materials have already been used. Among the photoreceptors using this type of photoreceptor, in particular, a machine-separated type having a charge generation layer and a charge transport layer as a VI layer has been put to practical use and is installed in copying machines and printers.

However, these photoreceptors generally suffer from decreased sensitivity, fluctuations in residual potential, decreased charging ability, durability of the electrophotographic surface against illuminating ice images, wear due to rubbing on the photoreceptor surface, etc.
The lifespan of these photoreceptors was unsatisfactory because of their poor mechanical durability against scratches and the like.

It is known that the cause of poor durability of the electrophotographic characteristic surface, especially the cause of image blurring, is the deterioration of the charge transport material in the photoreceptor surface layer due to ozone, No. 3, generated from the corona charger. In order to improve the durability of characteristics,
Substances with high oxidation potential are known as charge transport substances that are not easily degraded by ozone, NO, and the like.

It is known that the cause of poor mechanical durability is that paper, blades, cleaning members such as rollers, toner, etc. contact and rub against the surface of the photosensitive layer. Second, the surface of the photoconductor has good lubricity, reduces friction, makes the surface resistant to rubbing, and has good mold release properties to prevent toner filming, fusion, etc. Sliding materials such as fluororesin, fluorinated graphite, and polyolefin resin have been proposed as additives to the layer (Japanese Patent Application Laid-open Nos. 56-25746 and 56-257).
No. 49, No. 61-123850).

Furthermore, it has been proposed to apply a combination of the above-mentioned techniques for improving the durability of electronic properties and mechanical durability (Japanese Patent Laid-Open No. 63-30850), and this technique considerably extends the life of the photoreceptor. Something will happen.

[Problems to be Solved by the Invention] However, it has been pointed out that with the above technology, a new problem is that the photoreceptor pause memory phenomenon is likely to occur.

The dormant memory phenomenon is basically a corona virus! ! f. This is a phenomenon of deterioration caused by objects. After copying is complete, the rotation of the photoreceptor stops, and the charging ability of the photoreceptor in the area stopped near the corona charger decreases, and in the case of normal development, that area In the case of an inversion phenomenon, the image density becomes higher. This phenomenon is more likely to occur after using the photoreceptor for a long period of time, and the above improvements will extend the life of the photoreceptor. As a result, there is a slight improvement in the pause memory, but it is not perfect, and this poses a problem in small-sized copying machines and copying machines having cartridge-type photoreceptors.

Therefore, an object of the present invention is to provide a photoreceptor that has both durability in terms of electrophotographic properties and mechanical durability, and does not cause the pause memory phenomenon when used in an actual image forming device. be.

[Means for Solving the Problems] The problem is that in an electrophotographic photoreceptor having a photosensitive layer on a conductive substrate, at least the substrate and the most polished layer,
An electrophotographic photoreceptor characterized by containing one or more lubricant powders, one or more charge transport substances having an oxidation potential of 0.6 V or more, and a compound represented by the following general formula (1). Resolved.

In the present invention, (i) the addition of lubricant powder improves the slipperiness and abrasion resistance of the surface layer, It is effective in improving mechanical properties such as mold releasability for kimono, and (ii) I%i potential is 0.
．． The use of a charge transport material with a high oxidation potential of 6 V or more improves durability against corona products and contributes to stabilizing electrophotographic properties such as sensitivity, residual potential, and image blurring.

(iii) Furthermore, the compound of the general formula (1) is (i) (
Since the life of the photoreceptor is extended by means ii), it has the effect of preventing the photoreceptor stop memory phenomenon from occurring again.

Examples of the lubricant powder used in the present invention include tetrafluoroethylene resin powder, trifluorochloroethylene resin powder, and hexafluoroethylene propylene resin powder.

Fluorine resin powders such as ethylene dichloride resin powder, vinylidene fluoride resin powder, and copolymers of monomers constituting these polymers: polyethylene resin powder, polypropylene resin powder, polyhexene resin powder, Examples include polyolefin resin powder such as a copolymer of monomers constituting these bombers; fluorinated carbon powder.

Examples of charge transport substances having an oxidation potential of 0.6 or more used in the present invention include hydrazone compounds, stilbene compounds, carbazole compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, triarylmethane compounds, The higher the oxidation potential of the 6M1 cargo transporting substance such as polyarylalkanes, the more the durability of the photoreceptor improves, especially when the oxidation potential is 0.7V or more, the effect is even greater! It will be written by lll.

Charge transport materials generally have a low molecular weight and cannot be used to form a film by themselves, so a resin having film-forming properties is used as a binder to form a photosensitive layer in which the lubricant powder is dispersed.

There are no particular restrictions on the binder resin as long as it is a polymeric compound with film-forming properties, but the number of polymethacrylate esters, polycarbonate, polycarbonate, etc. Arylate, polyester, polysulfone, etc. are preferred.

The binder resin contained in the layer farthest from the substrate is usually 50 to 3 parts by weight per 100 parts by weight of the charge transport material.
About 0.00 parts by weight is used.

The content of the lubricant powder dispersed in the layer farthest from the substrate is based on the total amount of the charge transport substance and the binder (if the core layer contains a charge generation substance, the charge generation substance and the binder). 1.0 to 30% by weight is suitable, especially 2.0 to 30% by weight.
20% by weight is preferred.

If the content is less than 1.0% by weight, the surface modification effect by dispersing the lubricant powder will not be sufficient, while if it exceeds 30% by weight, the light transmittance will decrease and carrier mobility will also tend to decrease. There is.

Examples of the compound represented by the general formula (1) used in the present invention include the following compounds.

The content of the compound represented by the general formula (1) contained in the layer farthest from the substrate is determined by the amount of the compound represented by the general formula (1) contained in the charge transporting substance (if the partial layer contains a charge generating substance, the charge generating substance), and the binder. Usually 0.1 to 30% of the total amount of
0.2 to 10% by weight is particularly preferred. If the amount added is less than 0.1% by weight, the effect of preventing sleep memory is insufficient, and if it exceeds 30% by weight, the residual potential tends to increase.

When manufacturing the electrophotographic photoreceptor of the present invention, the substrate itself may be a conductive material such as aluminum,
Aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold, platinum, etc. can be used, and in addition, aluminum, aluminum alloy, indium oxide, tin oxide, indium oxide-tin oxide alloy A substrate made by coating plastic (e.g., carbon black, silver particles, etc.) with a layer formed by vacuum deposition using a vacuum evaporation method on a plastic material along with an appropriate binder, a substrate made by impregnating plastic or paper with conductive particles, or a conductive material. Plastics similar to polymers can also be used.

A subbing layer having barrier and adhesive functions can also be provided between the TL guiding layer and the photosensitive layer. The undercoat layer is made of casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyvinyl butyral, phenolic resin, polyamide (nylon 6, nylon 66,
Nylon 610, copolymerized nylon, alkoxymethyl nylon, etc.), polyurethane/tan, gelatin, aluminum oxide, etc.

The thickness of the undercoat layer is suitably 0.1 micron to 40 micron, preferably 0.3 micron to 3 micron.

As charge-generating substances, selenium-tellurium, pyrylium, thiopyrylium dyes, phthalocyanine pigments, anthrone pigments, dibenzpyrenequinone pigments, racetron pigments, trisazo pigments, disazo pigments, azo pigments, indigo pigments, quinacridone pigments, asymmetric quinocyanine ,
Quinocyanine and the like can be used.

As a method for dispersing the lubricant powder, general dispersion means such as a homogenizer, an ultrasonic wave, a ball mill, a vibration mill, a sand mill, an attritor, a roll mill, etc. can be used. After adding the lubricant powder to the binder dissolved in a suitable solvent, it is dispersed by the above-mentioned dispersion method. A surface layer coating liquid containing lubricant powder can be obtained by mixing an appropriate amount of this with a solution in which a binder, a charge transport substance, and the compound represented by the general formula (1) are dissolved in an appropriate solvent.

Coating methods include dip coating method, spray coating method, spinner coating method, beat coating method,
Coating methods such as Mayer bar coating method, blade coating method 1, roller coating method, and curtain coating method can be used. For drying, it is preferable to dry to the touch at room temperature and then heat dry.

Heat drying can be carried out at 30° C. to 200° C. for a period of 5 minutes to 2 hours, either stationary or with ventilation.

In the present invention, the oxidation potential is determined by using a saturated calomel electrode as a reference electrode and a 0.0. Using IN(n-Bu)4N■c+o and a setone solution as the electrolyte, the potential of the working electrode was swept by a potential sweeper, and the obtained "Tri current-current direction potential curve-K" position was directly converted to the oxidation potential. It was calculated as the value of

The present invention will be explained below with reference to Examples. Parts in the examples represent parts by weight.

Example 1 An aluminum cylinder of 80φ x 360mm was used as a base, and polyamide resin (product name: Amilan CM-80
Apply a 5% methanol solution of 00 Toshi Co., Ltd. by dipping method,
A subbing layer with a thickness of one meter was created for one house.

Next, 10 parts of a disazo pigment with the following structural formula was added to a polyvinyl butyral resin (trade name: S-LEC BXL, Tsukisui Kagaku)
Co., Ltd.) and 100 parts of cyclohexanone were dispersed for 20 hours using a sand mill device using 1φ glass beads. 50 to 100 (appropriate) parts of tetrahydrofuran were added to this dispersion and applied onto the undercoat layer, followed by drying at 100 DEG C. for 55 minutes to form a charge generating layer having a thickness of 0.151 parts and meters.

Next, a polyethylene resin powder (product name: Flocene 13142, manufactured by Seitetsu Kagaku) was used as a lubricant powder (polyolefin powder), and an oxidation potential 0 of the following structural formula was used as a charge transport substance.
．． 57V compound, the following structural formula (
A compound of C O″ \N/ \O CII 2 CI s (corresponding to the general formula (1)) and a bisphenol Z-type polycarbonate resin (manufactured by Kijin Kasei Co., Ltd.) Σ were prepared as a binder binder.

First, 20 parts of polycarbonate resin and the above charge transport material 2
0 parts, and the same as 0.2 parts of a recording memory prevention compound.
1 part was dissolved in 100 parts of monochlorobenzene, 6 parts of the above polyethylene resin powder was added thereto, dispersed for 50 hours in a stainless steel ball mill, and 20 parts of dichloroethane was further added to prepare a charge transport layer coating solution. This solution is applied on the generation layer, and 100. ”Hot dry for 90 minutes at
A charge transport layer having a thickness of 1 m was formed.

Comparative Example 1 A photoreceptor was prepared in the same manner as in Example 1 except that a compound having the following structural formula and an oxidation potential of 0.54 square meters was used as the charge transport material.

Comparative Example 2 A photoreceptor was produced in the same manner as in Example 1 except that no lubricant powder was added.

Comparative Example 3 Example 1 except that no compound for preventing dormant memory was added.
A photoreceptor was prepared in the same manner as above.

For the above photoconductor, the plate penetration i1. A 100,000-sheet durability test was carried out on a Canon copier NP-3525 which had been modified to have an Oms cleaning roller relative speed of 106%. The results are shown in Table 1.

Table 1 In Table 1, potential fluctuation is the dark potential (V
o) -650V, bright area potential (Vt, ) -150V,
The graph shows the change in absolute value after a 100,000-sheet durability test, with the residual potential (VR) set at -10V at that time. In addition, the pause memory refers to changes in image density between the area immediately below the corona charger and other areas, or the potential (Vo
) is expressed as the change in

As can be seen from Table 1, even after the 100,000-sheet durability test, the photoreceptor of Example 1 exhibited small potential fluctuations, small scratches on the surface layer, no pause memory, and exhibited high practical durability. On the other hand, in Comparative Example 1, which uses a charge transport material with a low oxidation potential, the potential fluctuation is large, and in Comparative Example 2, which does not use lubricant powder, the surface layer is extremely abraded. Potential fluctuations are occurring. Scratches also occur on the surface of the photoreceptor, and their effects are also visible on the image. Furthermore, the photoreceptor of Comparative Example 3 to which the compound for preventing pause memory was not added had excellent potential fluctuations and scraping as in Example 1, but pause memory occurred as much as 90V in potential, and there was no damage on the image. The influence is also noticeable.

Example 2 An aluminum cylinder of 80 φ x 360 mm was used as a conductive substrate, and a 5% methanol solution of polyamide resin (product name: Amilan CM-8000, manufactured by Toshi) was applied by dipping to a thickness of 0.5 p, m. A sublayer was created.

Next, 10 parts of a trisazo pigment having the following structural formula, 6 parts of polyvinyl butyral resin (trade name: Esle Nku 11L-3, manufactured by Sekisui Chemical), and 50 parts of cyclohexanone were dispersed in a sand mill device using glass beads. . 100 parts of methyl ethyl ketone was added to this dispersion and applied onto the undercoat layer to form a charge generation layer with a thickness of 0.2 p.m.

Next, as lubricant powder (fluorine-based resin powder), use 4-fluorochemically modified tyrene resin powder (trade name: Nilbron L-2, manufactured by Daikin Industries).
, a compound with the following structural formula as a charge transport material (oxidation potential 0
．． 81) A compound shown in Table 2 was prepared as a compound for preventing pause memory, and a bisphenol Z type polycarbonate resin (manufactured by Kijin Kasei Co., Ltd.) as a binding agent binder.

Table 2 Table 2 continued Photoreceptors were prepared using the compounds listed in Table 2 in the same manner as in Example 1. 1. For 20 parts of the cargo to be transported and 20 parts of the rejuvenating agent binder, the amount of fluororesin powder added was 2 parts, and the amount of the compound for preventing dormant memory was 0.
However, for Compound No. 1, there were five levels: 0.05 part, 0.1 part, 0.5 part, 1.0 part, and 4.0 part.

The results of evaluating the above photoreceptors are shown in Table 3.Equipped with a semiconductor laser with a single oscillation wavelength of 780 nm,
A laser beam printer of an image scan reversal development type was used, which had a cleaning blade with a penetration i of 1.0 mm and used a two-component developer consisting of toner and carrier. In Table 3, the potential fluctuation is the dark area potential at the beginning of the durability test.
600V, bright area potential -150V, and the residual potential at that time is set to -IOV, and shows the change in absolute value after a 10,000-sheet durability test. Regarding the pause memory, the measurement method is the same as in Example 1, but since 5-reversal development is used, the change in image density appears in the direction of increasing density, contrary to Example 1.

As can be seen from Table 3, the system in which the compound corresponding to the general formula (1) was added clearly had a better effect in preventing dormant memory than in the case in which compounds with other structures were added, and the effect of preventing harmful IJe on potential fluctuations, etc. In addition, even if the amount of the compound corresponding to the general formula (1) is changed, the effect of preventing sleep memory is high, and furthermore, the residual potential does not increase and the potential stability is high.

Example 3 An aluminum cylinder of 80 φ x 360 s
A 5% methanol solution of A-8000 (manufactured by Toshi Co., Ltd.) was applied by a dipping method to form an undercoat layer with a thickness of 1 m.

Next, 10 parts of a disazo pigment having the following structural formula, 6 parts of polyvinyl butyral resin (trade name: S-LEC BL-3, manufactured by Ueki Kagaku), and 50 parts of cyclohexanone were dispersed in a sand mill apparatus using glass beads. Add 100 parts of methyl ethyl ketone to this dispersion and apply it on the undercoat layer.
A charge generation layer having a thickness of 0.2 li and m was formed.

Next, fluorinated graphite (manufactured by Daikin Industries, Ltd.) was used as a fluorinated carbon powder, the same compound as in Example 1 was used as a dormant memory prevention compound, the compound shown in Table 4 was used as a charge transport substance, and bisphenol was used as a binder. Z-type car recarbonate resin (manufactured by Konjin Kasei) was prepared.

Table 4 Photoreceptors were produced using the charge transport materials listed in Table 4 in the same manner as in Example 1. The amount of fluorinated graphite powder added was 2 parts, and the amount of the compound for preventing dormant memory was 0.
．． This is part 2.

The above photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 5.

As can be seen from the table, charge transport substances with an oxidation potential of less than 0.6 are excellent in preventing dormant memory;
It can be seen that the potential fluctuation is larger than when using 0.6 parts or more.

Example 4 An aluminum cylinder of 80φ x 360mm was used as a base, and polyamide resin (trade name: Amilan CM-8) was applied to it.
A 5% methanol solution (manufactured by Toshi Co., Ltd.) was applied by dipping to form an undercoat layer having a thickness of Lp-m.

Next, 10 parts of a disazo pigment with the following structural formula was added to polybilibinyl butyral resin (product name: Esle Nku BXL, ff
100 parts of cyclohexanone,
was dispersed for 20 hours using a sand mill device using 1φ glass beads. Add 50 to 10% of tetrahydrofuran to this dispersion.
Add 0 part ゛C on the undercoat layer? j;, i(j L/,
After drying at 100° C. for 5 minutes to form a charge generation layer with a thickness of 0.15 parts m, 4-fluorochemically modified tyrene resin powder (trade name Nilbron L-2, manufactured by Daikin Industries, Ltd.) was used as a fluorine-based resin powder. ), a compound with the following structural formula as a charge transport substance (oxidation potential 0.66V)
The same compound as in Example 1 was prepared as a compound for preventing pause memory, and bisphenol Z type polycarbonate resin (manufactured by Ondai Kasei) was prepared as a binding agent binder. Hereinafter, in the same manner as in Example 1, the amount of the 4-fluoro-modified tyrene resin powder added was adjusted to 1.0.10.0.30% by weight and 3% by weight based on the total amount of the surface charge transporting substance and the binder. A photoreceptor with a different standard was created.

The above photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 6.

As can be seen from the table, even if the amount of lubricant powder added is changed, it has a high effect of preventing abrasion of the photoreceptor, the surface is less likely to be scratched, and image stains due to toner filming are less likely to occur. There is no increase in residual potential and potential stability is good.

Example 5 An 80φ cylinder was coated on the substrate up to the undercoat layer in the same manner as in Example 4. Next, 15 parts of the hydrazone compound used in Example 1, 10 parts of polycarbonate Z resin, 50 parts of dichloromethane, and 10 parts of monochlorobenzene were added. Subtract the solution dissolved in the
A 15 gm thick charge transport layer was coated on the primary layer using the same mixture as used in Example 1: 4 parts of disazo pigment, 10 parts of polycarbonate Z resin, and 50 parts of cyclohexanone.
A CG dispersion liquid (2) was prepared by dispersing the mixture for 20 hours in a sand mill using 1φ glass beads.

Next, a fluorine-based acrylic oligomer, the above-mentioned hydrazone compound, and polycarbonate Z tree 11t1 were prepared as a dispersant for polytetrafluoromodified tyrene resin powder 1. First, 10 parts of polycarbonate resin, 4 parts of hydrazone compound, and 0.15 parts of fluorine-based acrylic oligomer are dissolved in 1 part of dichloromethane and 40 parts of monochlorobenzene.Next, 1.5 parts of poly(4-fluoroethylene resin) powder is dissolved in this solution. In addition, the mixture was dispersed in a stainless steel ball mill for 40 hours. Furthermore, 0.3 part of the dormant memory prevention compound used in Example 1 was added to this solution.
T solution ■ was prepared. This CG dispersion liquid ■ and CT liquid ■ are mixed into 1:
A coating material mixed in a ratio of 1.5 mH was applied on the charge transport layer to form a charge generation layer of 5 mH.

The copying machine used in Example 1 was modified so that it could be positively charged, and this photoreceptor was evaluated in the same manner as in Example 1, but even after the 10,000-sheet durability test, there were no potential fluctuations, photoreceptor scraping, or pause memory. A small, high-quality copy was obtained.

Comparative Example 4 As a comparative example of Example 5, a photoreceptor was prepared with a compound for preventing pause memory, and the same evaluation was conducted. △
VD = 160V.

[Effects of the Invention] According to the present invention, since it has excellent durability in terms of characteristics for electrophotography, the potential fluctuation of the photoreceptor is small, and because it has excellent mechanical durability, there is less abrasion of the photoreceptor. It is possible to obtain an excellent electrophotographic photoreceptor that has a long life, has a significantly suppressed photoreceptor stop memory, and does not have local shading abnormalities in the resulting images.

Claims (5)

[Claims] (1) In an electrophotographic photoreceptor having a photosensitive layer on a conductive substrate, at least the layer farthest from the substrate includes one or more lubricant powders, one or more charge transport substances having an oxidation potential of 0.6 V or more, and an electrophotographic photoreceptor containing a compound represented by the following general formula (1). General formula (1) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [In the formula, R is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, n is a positive integer, X_1 is ▲ Numerical formulas, chemical formulas, tables, etc. There are ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼,
X_2 is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms] (2) The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer has a laminated structure consisting of a charge generation layer and a charge transport layer, and the charge transport layer is provided on the charge generation layer. (3) The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer has a laminated structure consisting of a charge generation layer and a charge transport layer, and the charge generation layer is provided on the charge transport layer. (4) The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer comprises a single layer containing a charge generating substance and a charge transporting substance. (5) The electrophotographic photoreceptor according to claim 1, wherein the lubricant powder is a fluororesin powder, a polyolefin resin powder, or a fluorocarbon powder.