JP2002296819A - Electrophotographic photoreceptor, process cartridge provided with the photoreceptor and electrophotographic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor less liable to cause a potential change in continuous use in a low humidity environment without impairing superior characteristics peculiar to a conventional electrophotographic photoreceptor using TiOPc, and to provide a process cartridge provided with the electrophotographic photoreceptor and an electrophotographic apparatus. SOLUTION: In the electrophotographic photoreceptor having an electric charge generating layer and an electric charge transporting layer on an electrically conductive substrate, the electric charge generating layer contains oxy- titanium phthalocyanine, a coating material for forming the electric charge transporting layer has 0.1-1 mass% water content and the drying temperature of the coating material is <=110 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic photoreceptor,
More particularly, the present invention relates to an electrophotographic photosensitive member having high sensitivity and excellent potential stability, and a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

[0002]

2. Description of the Related Art Electrophotography is disclosed in U.S. Pat. No. 2,297,691.
As shown in the publication, a photoconductive material comprising a support coated with an insulating material is used in which the electric resistance changes according to the amount of irradiation received during image exposure, and in a dark place. The basic characteristics required of an electrophotographic photoreceptor using this photoconductive material are (1) that it can be charged to an appropriate potential in a dark place, (2) that there is little dissipation of electric charge in a dark place, 3) The charge can be quickly dissipated by light irradiation.

Conventionally, selenium,
Inorganic photoreceptors having a photosensitive layer containing an inorganic photoconductive compound such as zinc oxide or cadmium sulfide as a main component have been widely used. However, they satisfy the above conditions (1) to (3), but cannot always satisfy thermal stability, moisture resistance, durability and productivity. For example, when selenium is crystallized, its characteristics as a photoreceptor deteriorate, making it difficult to manufacture. In addition, heat, fingerprints, and the like cause crystallization, resulting in crystallization and deterioration of the performance as a photoreceptor. Also,
Cadmium sulfide has problems in moisture resistance and durability, and zinc oxide has problems in smoothness, hardness and friction resistance. Furthermore, the photosensitive wavelength region of many inorganic photosensitive members is limited. For example, the photosensitive wavelength region of selenium is the blue region, and has little sensitivity in the red region.

For this reason, various methods have been proposed to extend the photosensitivity to the long wavelength region, but there are many restrictions on the selection of the photosensitive wavelength region. Even when zinc oxide or cadmium sulfide is used as the photoreceptor, the photosensitive wavelength range of the photoreceptor itself is narrow, and it is necessary to add various sensitizers.

In order to overcome the disadvantages of these inorganic photoreceptors, electrophotographic photoreceptors containing various organic photoconductive compounds as main components have been actively developed in recent years. For example, U.S. Pat. No. 3,838,851 discloses a photoreceptor having a charge transporting layer containing triallylpyrazolin, U.S. Pat.
Japanese Patent No. 871882 discloses a photoreceptor including a charge generation layer composed of a derivative of a perylene pigment and a charge transport layer composed of a condensate of 3-propylene and formaldehyde.

A photoreceptor using a bisazo pigment or a trisazo pigment as a charge generating substance is disclosed in
JP-A-33445, JP-A-56-46237 and JP-A-60-111249 are known.

Further, the photosensitive wavelength range of the electrophotographic photosensitive member can be freely selected depending on the organic photoconductive compound. For example, for azo organic pigments,
JP-A-61-272754 and JP-A-56-16
JP 7759 discloses substances exhibiting high sensitivity in the visible region, and JP-A-57-195767 and JP-A-61-228453 disclose substances having sensitivity up to the infrared region. Have been.

Among these materials, those having sensitivity in the infrared region are used in laser beam printers (hereinafter abbreviated as LBPs), LED printers, and the like, which have been making remarkable progress in recent years, and the demand frequency is increasing.

Particularly, in recent years, oxytitanium phthalocyanine (hereinafter referred to as TiOP) has been used as a material having high sensitivity in the infrared region.
c). It is known that TiOPc takes many crystal forms.
No. 66 and Japanese Patent Application Laid-Open No. 3-128973 disclose crystal forms.

[0010]

However, an electrophotographic photoreceptor using TiOPc as a charge generating material has a very high sensitivity and a sensitivity up to the infrared region, but it is not suitable for use in a low humidity environment. There is a drawback that the potential fluctuates greatly during continuous durability.

Accordingly, an object of the present invention is to provide a conventional TiOP
Electrophotographic photoreceptor that does not easily cause potential fluctuation during continuous durability in a low humidity environment without impairing the excellent characteristics of the electrophotographic photoreceptor using c, a process cartridge having the electrophotographic photoreceptor, and an electrophotographic It is to provide a device.

[0012]

According to the present invention, there is provided an electrophotographic photosensitive member having a charge generation layer and a charge transport layer on a conductive support, wherein the charge generation layer contains oxytitanium phthalocyanine, and the charge transport layer 0.1 to 1 paint for forming
An electrophotographic photosensitive member having a water content of 1% by mass and a drying temperature of the paint is 110 ° C. or lower, and a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

When TiOPc is used for the charge generation layer, it is possible to produce an electrophotographic photoreceptor with extremely high sensitivity, but there is a disadvantage that the potential fluctuates greatly during continuous durability in a low humidity environment.

As a result of repeated investigations to improve such disadvantages, it was found that water was added to the paint for forming the charge transport layer laminated on the charge generation layer, and the water content of the paint was 0.1 to 1% by mass. By adjusting the paint drying temperature after applying the charge transport layer forming paint to 110 ° C. or less, it is possible to eliminate the disadvantage that the potential fluctuates greatly during continuous durability in a low humidity environment, The effect is that the charge transport layer forming paint contains a solvent containing a component having an affinity for water, thereby retaining the water added to the charge transport layer,
It has been found that it is further improved.

As a result, it is possible to obtain an electrophotographic photosensitive member having high sensitivity and little fluctuation in potential due to continuous durability under a low humidity environment.

Next, the present invention will be described in accordance with a specific configuration.

The conductive support may be any conductive material, and may be a metal such as aluminum or stainless steel, or a metal provided with a conductive layer, plastic, paper, or the like. And the like.

When the image input is a laser beam such as LBP, it is preferable to provide a conductive layer for preventing interference fringes due to scattering. This can be formed by dispersing conductive powder such as carbon black and metal particles in a binder resin. The thickness of the conductive layer is preferably from 5 to 40 μm, more preferably from 10 to 30 μm.

It is preferable to provide an intermediate layer made of polyamide thereon. The thickness of the intermediate layer is preferably from 0.2 to 5 μm, more preferably from 0.5 to 1 μm.

On the intermediate layer, TiO is used as a charge generating material.
A charge-generating layer is formed by applying a paint in which Pc is dispersed in a suitable binder resin and drying the paint.

TiOPc usable in the present invention includes a flag angle 2θ ± in X-ray diffraction of CuKα.
9.0%, 14.2%, 23.9% and 2 of 0.2%
A crystalline form of TiOPc having a strong peak at 7.1 ° is preferred.

Examples of the binder resin include a polyester resin, a polyacryl resin, a polyvinyl carbazole resin, a phenoxy resin, a polycarbonate resin, a polystyrene resin, a polyvinyl acetate resin, a polysulfone resin, a polyarylate resin, a vinylidene chloride-acrylonitrilo copolymer resin, and a polyvinyl resin. Examples include but are not limited to benzal resin. These may be used alone, as a mixture, or as one or more kinds of copolymer polymers. The ratio of the binder resin to the charge generating substance is preferably 1/5 to 5/1, and more preferably 1/2 to 3/1.

The thickness of the charge generating layer is preferably 5 μm or less, more preferably 0.01 to 2 μm.

Further, additives such as various sensitizers and deterioration inhibitors may be added to the charge generation layer.

The charge transport layer is mainly formed by applying a coating material in which a charge transport material and a binder resin are dissolved in a solvent and drying the coating material. Examples of the charge transport material used include various triarylamine compounds, hydrazone compounds, stilbene compounds, pyrazoline compounds,
Oxazole compounds, triallylmethane compounds, thiazole compounds and the like can be mentioned. As the binder resin, the same resin as that used for the charge generation layer can be used.

Water is added to the coating material for forming the charge transport layer, and the water content in the coating material is adjusted to be 0.1 to 1% by mass. The paint drying temperature is 110 ° C. or less. Furthermore,
It is preferable that the coating material for forming a charge transport layer contains a solvent having an affinity for water.

As a method of applying these photosensitive layers, dipping, spray coating, spinner coating, bead coating, blade coating, beam coating, and the like can be used.

FIG. 1 shows an example of a schematic configuration of an electrophotographic apparatus having a process cartridge having the electrophotographic photosensitive member of the present invention. In FIG. 1, reference numeral 1 denotes a drum-type photoconductor of the present invention as an image carrier, which is driven to rotate around an axis 1a in a direction indicated by an arrow at a predetermined peripheral speed. The photosensitive member 1 is uniformly charged with a predetermined positive or negative potential on its peripheral surface by a charging means 2 during the rotation process, and then exposed (L slit exposure and laser beam scanning exposure) by an exposure means (not shown) in an exposure section 3. Etc.). As a result, an electrostatic latent image corresponding to the exposure image is sequentially formed on the peripheral surface of the photoconductor.

The electrostatic latent image is then developed with toner by developing means 4, and the toner image is transferred by a transfer means 5 from a paper feeding unit (not shown) to the photosensitive body 1 between the transfer means 5 and the rotation of the photosensitive body 1. The transfer material P is sequentially transferred onto the surface of the transfer material P which is synchronously taken out and fed. The transfer material P having undergone the image transfer is separated from the photoreceptor surface, introduced into the image fixing means 8 and subjected to fixing to be printed out as a copy outside the machine. The surface of the photoreceptor 1 after the transfer is cleaned by a cleaning unit 6 to remove the untransferred toner, and is further subjected to a charge removal process by a pre-exposure unit 7 to be used repeatedly for image formation.

As the uniform charging means 2 for the photosensitive member 1, a corona charging device is generally widely used. Also, the corona transfer means is generally widely used for the transfer device 5. As an electrophotographic apparatus, a plurality of components, such as the above-described photoconductor, developing means, and cleaning means, are integrally connected as an apparatus unit, and this unit is configured to be detachable from the apparatus body. You may. For example, the photoreceptor 1 and the cleaning means 6 may be integrated into one apparatus unit, and may be detachable using a guide means such as a rail of the apparatus body. At this time, the above-described device unit may be provided with a charging unit and / or a developing unit.

When the electrophotographic apparatus is used as a copier or a printer, the exposure L is a signal reflected from or transmitted from the original, or a read signal of the original, and a laser beam is scanned by this signal, or an LED array is used. Drive or
Alternatively, it is performed by driving a liquid crystal shutter array.

The electrophotographic photoreceptor of the present invention is used not only for an electrophotographic copying machine but also for a laser beam printer,
It can be widely used in electrophotographic applications such as RT printers, LED printers, liquid crystal printers, and laser plate making.

Next, a production example of TiOPc used in the present invention will be described.

(Production Example 1) α-chloronaphthalene 100
g, 5.0 g of o-phthalodinitrile and 2.0 g of titanium tetrachloride were heated and stirred at 200 ° C. for 3 hours, cooled to 50 ° C., and the precipitated crystals were separated by filtration to obtain a paste of dichlorotitanium phthalocyanine. . Then, change this to 10
N, N'-dimethylformamide 100 heated to 0 ° C
Wash with stirring, and then add methanol 100m at 60 ° C.
The washing was repeated twice with 1 and filtered. Further, the obtained paste was stirred in 100 ml of deionized water at 80 ° C. for 1 hour and filtered to obtain a blue TiOPc crystal. The yield was 4.3 g.

The elemental analysis values of this compound were as follows.

Elemental analysis value (C ₃₂ H ₁₆ N ₈ TiO) CH N Cl Calculated value (%) 66.68 2.80 19.44 0.00 Actual value (%) 66.50 2.99 19.42 0.47

Next, the crystals were dissolved in 30 ml of concentrated sulfuric acid, re-precipitated by dropping into 300 ml of deionized water at 20 ° C. with stirring, filtered, washed sufficiently with water, and then mixed with amorphous Ti.
OPc was obtained. 4.0 g of this amorphous TiOPc was suspended and stirred in 100 ml of methanol at room temperature (22 ° C.) for 8 hours, filtered and dried under reduced pressure to obtain low-crystalline TiOPc. Furthermore, low crystallinity TiOPc2.
Add 0 ml of n-butyl ether to 0 g and add 1 mmφ
Milling with glass beads at room temperature (22 ° C)
Time went. The solid content was taken out of the dispersion, sufficiently washed with methanol and water, and dried. The yield was 1.8 g.

This crystal has a diffraction angle 2θ ± in X-ray diffraction.
9.0 ゜, 14.2 ゜, 23.9 ゜ and 2 of 0.2 ゜
It had a strong peak at 7.1 °.

[0040]

Embodiments will be described below in accordance with embodiments. In the examples,
"Parts" indicates parts by mass, and "%" indicates mass%.

(Example 1) A 30φ, 260mm aluminum cylinder was used as a support, and a coating composed of the following materials was applied to the support by a dipping method, and was thermally cured at 140 ° C for 30 minutes. A conductive layer having a thickness of 18 μm was formed.

Conductive pigment: tin oxide-coated titanium oxide 10 parts Resistance adjusting pigment: titanium oxide 10 parts Binder resin: phenol resin 10 parts Leveling agent: silicone oil 0.001 part Solvent: methanol / methyl cellosolve = 1/1 ... 20 copies

Next, a solution obtained by dissolving 3 parts of N-methoxymethylated nylon and 3 parts of copolymerized nylon in 65 parts of methanol and 30 parts of n-butanol was applied thereon by dipping to obtain a film having a thickness of 1%. An intermediate layer having a thickness of 0.0 μm was formed.

Next, 3 parts of the pigment prepared in Production Example 1, 2 parts of polyvinyl butyral (trade name: SREC BM-2, manufactured by Sekisui Chemical Co., Ltd.) and 80 parts of cyclohexanone were mixed with each other by φ1 m.
After dispersion for 4 hours by a sand mill using m glass beads, 115 parts of methyl ethyl ketone was added to obtain a dispersion for a charge generation layer. This was applied on the intermediate layer by dipping to form a charge generation layer having a thickness of 0.2 μm.

The polyvinyl butyral used was treated by the following method. 1 part of butyral was dissolved in 10 parts of dichloromethane for a reagent, filtered through 5C filter paper, and then added dropwise to 100 parts of methanol. After decanting, 60 parts of methanol was added and washed with stirring. The steps after decanting were repeated three times. After that, butyral was collected by filtration and dried under reduced pressure.

Next, 10 parts of an amine compound having the following structural formula

[0047]

Embedded image And 10 parts of bisphenol Z polycarbonate resin (viscosity average molecular weight 22,000) were dissolved in 50 parts of monochlorobenzene and 10 parts of dichloromethane. Further, water was added to the paint to adjust the water content to 0.3% (for measuring the water content, a moisture meter AQV manufactured by Hiranuma Sangyo Co., Ltd.
-200). This paint was applied on the above-mentioned charge generation layer by dipping, and dried at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 20 μm.

Example 2 A photoconductor was prepared in the same manner as in Example 1, except that the drying temperature of the charge transport layer in Example 1 was changed to 100 ° C.

Example 3 A photoconductor was prepared by the same way as that of Example 1 except that the content of water was adjusted to 0.5% by adding water to the coating material for forming a charge transport layer of Example 1.

Example 4 A photoconductor was prepared in the same manner as in Example 2, except that water was added to the paint for forming a charge transport layer of Example 2 to reduce the water content to 0.5%.

Example 5 A photoconductor was prepared by the same way as that of Example 1 except that the content of water was changed to 1% by adding water to the coating material for forming the charge transport layer of Example 1.

Example 6 A photoconductor was prepared in the same manner as in Example 2, except that the water content was 1% by adding water to the charge transporting layer forming coating material of Example 2.

Example 7 The solvent for the coating material for forming a charge transport layer in Example 1 was changed from 10 parts of dichloromethane to 10 parts of methylal.
A photoconductor was prepared in the same manner as in Example 1, except that the parts were changed.

Example 8 The solvent of the coating material for forming a charge transport layer in Example 2 was changed from 10 parts of dichloromethane to 10 parts of methylal.
A photoconductor was prepared in the same manner as in Example 2, except that the parts were changed.

(Example 9) The solvent of the coating material for forming a charge transport layer in Example 3 was changed from 10 parts of dichloromethane to 10 parts of methylal.
A photoconductor was prepared in the same manner as in Example 3, except that the parts were changed to parts.

(Example 10) The solvent for the coating material for forming a charge transport layer in Example 4 was changed from 10 parts of dichloromethane to methylal 1
A photoconductor was prepared in the same manner as in Example 4, except that the amount was changed to 0.

Example 11 The solvent for the coating material for forming a charge transport layer of Example 5 was prepared by adding 10 parts of dichloromethane to methylal 1
A photoconductor was prepared in the same manner as in Example 5, except that the amount was changed to 0.

(Example 12) The solvent for the coating material for forming a charge transporting layer of Example 6 was changed from 10 parts of dichloromethane to methylal 1
A photoconductor was prepared in the same manner as in Example 6, except that the amount was changed to 0.

(Comparative Example 1) Water was added to the charge transporting layer forming paint of Example 1 so that the water content was 0.05%, the charge transporting layer drying temperature was 130 ° C, and the charge transporting layer forming paint was added. A photoconductor was prepared by the same way as that of Example 1 except that the solvent was changed from 50 parts of monochlorobenzene to 10 parts of dichloromethane, to 60 parts of monochlorobenzene.

(Comparative Example 2) A photoconductor was prepared in the same manner as in Example 1, except that the water content was adjusted to 0.05% by adding water to the coating material for forming the charge transport layer of Example 1.

Comparative Example 3 A photoconductor was prepared by the same way as that of Example 7 except that the water content was 0.05% by adding water to the charge transport layer-forming coating material of Example 7.

Comparative Example 4 A photoconductor was prepared in the same manner as in Comparative Example 1, except that the water content was 3% by adding water to the paint for forming the charge transport layer of Comparative Example 1.

Comparative Example 5 A photoconductor was prepared in the same manner as in Example 1, except that the water content was 3% by adding water to the paint for forming the charge transport layer of Example 1.

Comparative Example 6 A photoconductor was prepared by the same way as that of Example 7 except that the content of water was changed to 3% by adding water to the coating material for forming a charge transport layer of Example 7.

These photosensitive members were evaluated for images. For evaluation, LBP manufactured by Canon was used. Environment is 15
° C and 10% RH. In the evaluation of the photoreceptor, the dark part potential was set to -700 V and the light part potential was set to -200 V, and the fluctuation amounts ΔVd and ΔVl of the dark part potential and the light part potential after continuous running of 3000 sheets were measured.

The results are shown in Table 1.

[0067]

[Table 1]

As described above, as described in the embodiment, TiOPc
Is used as a charge generation material, and water is added to the charge transport layer forming paint laminated on the charge generation layer, so that the paint has a water content of 0.1.
By adjusting the amount to be 1 to 1% and keeping the paint drying temperature after applying the charge transport layer-forming paint at 110 ° C. or lower, the moisture added to the charge transport layer is retained, thereby achieving high sensitivity. An electrophotographic photoreceptor having a small potential fluctuation during continuous durability in a low humidity environment can be produced.

Further, since the charge transporting layer-forming coating contains a solvent having an affinity for water, the water added in the charge transporting layer can be retained, so that the coating composition has higher sensitivity and continuous durability under a low humidity environment. Thus, an electrophotographic photosensitive member having less potential fluctuation can be produced.

TiOPc has a diffraction angle of 2θ ± 0.2 ° in the X-ray diffraction spectrum of 9.0 °, 14.2 °,
The effect is particularly remarkable in the case of crystals having strong peaks at 23.9 ° and 27.1 °.

Further, as shown in the comparative examples, the water content of the coating material for forming the charge transport layer is too small or too large, the drying temperature of the charge transport layer is too high, It is clear that the potential fluctuates greatly and the effect is not so much obtained.

[0072]

According to the electrophotographic photoreceptor of the present invention, a stable electrophotographic photoreceptor having little potential fluctuation during continuous durability in a low humidity environment can be obtained without deteriorating excellent electrophotographic characteristics. Further, the same effects can be obtained in a process cartridge and an electrophotographic apparatus in which the electrophotographic photosensitive member of the present invention is combined.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an electrophotographic apparatus having a process cartridge having an electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging means 3 Exposure part 4 Developing means 5 Transfer means 6 Cleaning means 7 Pre-exposure means 8 Image fixing means

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H068 AA19 AA35 AA37 BA39 CA60 EA14 EA19 FA27

Claims (5)

[Claims] 1. An electrophotographic photosensitive member having a charge generation layer and a charge transport layer on a conductive support, wherein the charge generation layer contains oxytitanium phthalocyanine, and the coating material for forming the charge transport layer is 0.1%. An electrophotographic photoreceptor having a water content of about 1% by mass and a drying temperature of the coating material of 110 ° C. or lower. 2. The method according to claim 1, wherein the oxytitanium phthalocyanine is C
2. The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor has strong peaks at 9.0, 14.2, 23.9 and 27.1 at flag angles 2θ ± 0.2 ° in X-ray diffraction of uKα. 3. The electrophotographic photosensitive member according to claim 1, wherein the coating material for forming the charge transport layer contains a solvent having an affinity for water. 4. An electrophotographic photoreceptor according to claim 1, wherein said electrophotographic photoreceptor is charged by a charging means for charging said electrophotographic photoreceptor, and said electrophotographic photoreceptor on which an electrostatic latent image is formed by exposure is a toner. It is integrally supported together with at least one means selected from the group consisting of a developing means for developing and a cleaning means for collecting residual toner on the electrophotographic photoreceptor after the transfer step, and is detachable from the main body of the electrophotographic apparatus. A process cartridge. 5. The electrophotographic photosensitive member according to claim 1, a charging unit for charging the electrophotographic photosensitive member,
Exposure means for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image, developing means for developing the electrophotographic photosensitive member on which the electrostatic latent image is formed with toner, and toner image on the electrophotographic photosensitive member An electrophotographic apparatus having a transfer unit for transferring the image to a transfer material.