JPH1165149A - Electrophotographic photoreceptor, process cartridge having the electrophotographic photoreceptor, and electrophotographic apparatus - Google Patents

Abstract

(57) [Problem] To provide an electrophotographic photoreceptor having less potential fluctuation and image defects while maintaining high sensitivity as excellent electrophotographic characteristics. The support is an aluminum cylinder which has been subjected to an alumite treatment, and the photosensitive layer has a diffraction angle of 2θ ± 0.2 ° of 9.0 °, 1θ ± 0.2 ° in CuKα characteristic X-ray diffraction.
An electrophotographic photoreceptor comprising simultaneously an oxytitanium phthalocyanine having a strong peak at 4.2 °, 23.9 ° and 27.1 ° and an azoxy pigment having the following structural formula.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic photosensitive member, an inorganic photosensitive member having a photosensitive layer mainly composed of an inorganic photoconductive substance such as zinc oxide and cadmium sulfide has been widely used. However, thermal stability, moisture resistance, durability, productivity, and the like are not always satisfactory. On the other hand, for the purpose of overcoming the drawbacks of the inorganic photoreceptor, organic photoreceptors having a photosensitive layer containing various organic photoconductive substances as main components have been actively developed. Above all, a function-separated type photoconductor using a combination of a charge generation material and a charge transport material can significantly improve the sensitivity, which is a disadvantage of a photoconductor using an organic photoconductive material, and is particularly attracting attention. I have.

In general, an electrophotographic photoreceptor comprises a support and a photosensitive layer formed on the support. The support covers defects of the support, improves coating properties of the photosensitive layer, and adheres the photosensitive layer to the support. It is effective to provide an intermediate layer between the photosensitive layer and the support to improve the chargeability, protect the photosensitive layer against electrical destruction, improve the chargeability, and improve the charge injection property from the support to the photosensitive layer. is there.

In recent years, oxytitanium phthalocyanine (hereinafter referred to as TiOPc) has been used as a charge-generating substance having particularly high sensitivity.
It is known that an electrophotographic photoreceptor using TiOPc for the charge generation layer has a very high sensitivity. However, since the sensitivity is high, the absolute number of carriers is large and the photoreceptor has a large number of carriers.
There is a drawback that electrons after the injection of electrons easily stay in the charge generation layer, and as a kind of memory, potential fluctuation easily occurs. This is particularly remarkable in the case of a photoreceptor provided with an intermediate layer, and in an environment such as low temperature and low humidity, the volume resistance of the charge generation layer and the intermediate layer to electrons increases.
Such a potential fluctuation increases.

A phenomenon in which such potential fluctuations, that is, the accumulation of electrons, appears in an actual image is a ghost phenomenon. In particular, when electrons stay at the interface between the charge generation layer and the intermediate layer, they appear as an increase in the light-area potential during printing, and when used in a reversal development system, the sensitivity at the place where light was applied during pre-printing slows down. If you take a full black image at the next print, the previous print part will appear white,
The negative ghost phenomenon appears remarkably.

Therefore, TiOP is used for such a charge generation layer.
As one means for reducing potential fluctuation, which is a major drawback of photoconductors using c, there is a report that an intermediate layer contains a conductive filler having very fine particles and good dispersibility.
In particular, there is a report that barium sulfate fine particles coated with tin oxide is used for the intermediate layer (Japanese Patent Application No. 5-276936). However, these barium sulfate fine particles have much better dispersibility than conventional conductive fillers. Does not cause local resistance change. Further, since the particles are very fine, there are many injection points of the electrons, and the electrons staying in the charge generation layer can be quickly flowed toward the support. It is also reported that stable potential and image characteristics can be obtained even under extreme environments such as high temperature and high humidity and low temperature and low humidity.

However, although the number of injection points of electrons has increased, the amount of carriers generated by TiOPc is so large that it is not possible to eliminate the stagnation of electrons in the charge generation layer at all, and the potential characteristics and image characteristics are considerably high. Improved but needs further improvement.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor which has less potential fluctuation and image defects while maintaining high sensitivity as excellent electrophotographic characteristics.
Another object of the present invention is to provide a process cartridge having the electrophotographic photosensitive member and an electrophotographic apparatus.

[0009]

According to the present invention, an aluminum cylinder whose support is anodized, and
An electrophotographic photoreceptor characterized in that a phthalocyanine and an azo pigment are simultaneously contained in a photosensitive layer.

The phthalocyanine used in the present invention has a diffraction angle of at least 27 in CuKα characteristic X-ray diffraction.
It is an oxytitanium phthalocyanine having a main peak at 1 ° ± 0.2θ, and further, 2θ ± 0.2 ° in the CuKα characteristic X-ray diffraction is 9.0 °, 1θ ± 0.2 °.
Oxytitanium phthalocyanine having a strong peak at 4.2 °, 23.9 ° and 27.1 ° is preferred.

The azo pigment used in the present invention is preferably selected from the group consisting of azo pigments having a central skeleton represented by the following general formulas (1) to (4). General formula (1)

Embedded image General formula (2)

Embedded image General formula (3)

Embedded image General formula (4)

Embedded image Ar, Ar ′ and Ar ″ in the general formulas (1) to (4)
Represents a coupler residue.

The thickness of the alumite layer of the support of the electrophotographic photosensitive member of the present invention is 1 to 15 μm.
The alumite layer can be subjected to a sealing treatment.

Further, the present invention provides an electrophotographic photoreceptor of the present invention,
And integrally support at least one means selected from the group consisting of charging means, developing means and cleaning means,
It comprises a process cartridge which is detachable from the main body of the electrophotographic apparatus.

Further, the present invention provides an electrophotographic photoreceptor of the present invention,
The image forming apparatus includes an electrophotographic apparatus including a charging unit, an image exposing unit, a developing unit, and a transfer unit.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In the case of an electrophotographic photosensitive member using TiOPc for a charge generation layer, the retention of electrons in the charge generation layer, that is, the potential fluctuation is reduced by using barium sulfate fine particles for an intermediate layer. Can, but not enough. Thus, the present inventors have further developed a method for reducing the potential fluctuation by using a conductive support treated with alumite and simultaneously using TiOPc and an azo pigment as the charge generating material of the charge generating layer. Have been found to be able to improve image defects, and to achieve higher sensitivity, thereby achieving the present invention.

Although it is not clear why the potential fluctuation is reduced by adding an azo pigment to TiOPc,
This is considered to be because electrons in an excited state which cause a large amount of stagnation due to TiOPc easily return to the ground state by the azo pigment.

Next, the structure of the electrophotographic photosensitive member of the present invention will be described.

The support is made of anodized aluminum, for example, JIS1050, 10
70, 1080, etc., pure aluminum, Al-Mg based alloy, Al-Cu based alloy, Al-Si based alloy, Al-Mg
Aluminum alloys such as Al-Si alloys, Al-Cu-Si alloys, and aluminum alloys JI that are Al-Mn alloys
Examples include H14 or H16 of S3003, and anodized aluminum alloy such as T3 of JIS6063 alloy which is an Al-Si alloy.

The support made of anodized aluminum may have an alumite-processed layer having an appropriate thickness. However, in order to secure conductivity on the surface of the support, the thickness is 1 to 15 μm, preferably 6 μm. It has an alumite processed layer of up to 12 μm. When the thickness of the anodized layer is less than 1 μm, not only the corrosion resistance and abrasion resistance of the support but also the adhesion to the organic photosensitive layer is not sufficient. The carrier is not sufficiently injected from the substrate, and the residual potential increases due to repeated use of the photoconductor.

The alumite processing is performed by using oxalic acid, sulfuric acid,
Using chromic acid or boric acid aqueous solution as the electrolyte,
Depending on the type of the electrolytic solution, for example, an applied voltage of 10 to 150
V and anodizing at a current density of 0.1 to 500 A / m ² for a desired time.

An organic photosensitive layer may be formed directly on the alumite-processed surface of the support. However, since the alumite-processed layer is porous, easily contaminated, and has insufficient corrosion resistance, etc. It is preferable to form an organic photosensitive layer on the inactivated support obtained by sealing the above.

The sealing treatment of the alumite-treated layer is carried out by a conventional method, for example, steam treatment, boiling water treatment, nickel acetate treatment with a solution containing nickel acetate and cobalt acetate, and heavy treatment such as potassium dichromate. Dichromate treatment with chromate solution, soda silicate treatment with sodium silicate solution, immersion of oleic acid, stearic acid, etc., oil and fat treatment by coating, silicone resin, phenol resin, etc. It can be performed by subjecting the resin to a resin impregnation treatment by dipping or coating. Among the above treatments, a nickel acetate treatment that can efficiently close the micropores by a hydration reaction is preferable.

As the charge generating substance, phthalocyanine and an azo pigment may be used, and one or more other azo organic pigments may be mixed.

The phthalocyanine is an oxytitanium phthalocyanine having a main peak at least at a diffraction angle of 27.1 ° ± 0.2θ in the CuKα characteristic X-ray diffraction. ± 0.2 ° is 9.0 °, 14.2 °, 23.9 °
And oxytitanium phthalocyanine having a strong peak at 27.1 °.

The azo pigments are represented by the general formula (1)
The azo pigment represented by (4) is preferable, and the azo pigment represented by the following structural formula (1) is particularly preferable.

In the general formulas (1) to (4), Ar, Ar ′,
Examples of the coupler residue represented by Ar ″ include the following couplers:
Selected from groups represented by residues (1) to (5),
Species or a combination of two or more species may be used. Coupler residue (1)

Embedded image Coupler residue (2)

Embedded image Coupler residue (3)

Embedded image Coupler residue (4)

Embedded image Coupler residue (5)

Embedded image X in the coupler residues (1) to (5) represents a hydrogen atom, a halogen atom or an alkyl group.

Structural formula (1)

Embedded image

The ratio of the azo pigment to phthalocyanine is preferably 1 to 200%, more preferably 5 to 100%.

In the case of a laminated photoreceptor, a binder resin is added to the charge generation layer as needed. As the binder resin for the charge generation layer, for example, acrylic resin, polyester, polyamide, polyvinyl acetate, polycarbonate,
Thermoplastic resins such as polyvinyl butyral and polyvinyl benzal; and thermosetting resins such as polyurethane, phenolic resin and epoxy resin. Further, additives can be added as needed.

The charge transporting layer is generally formed by adding a solvent to a charge transporting substance and a binder resin to prepare a coating solution and applying the coating solution. Examples of the charge transport material include hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triarylmethane compounds. As the solvent, binder-resin, those having good solubility in the charge transporting substance, for example, ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, cyclohexanone,
Ethers such as diethyl ether and tetrahydrofuran; esters such as ethyl acetate and butyl acetate; hydrocarbons such as toluene and benzene; and halogenated hydrocarbons such as chlorobenzene and dichloromethane.

The ratio of the charge transporting substance to the binder resin depends on the type of the binder resin and the charge transporting substance, but is generally preferably 20 to 70%, more preferably 30 to 65%. If the ratio of the charge transport material is small, sufficient sensitivity cannot be obtained, and if the ratio of the charge transport material is too large, the strength of the surface layer is reduced and the surface layer is easily damaged.

If necessary, a lubricant such as an inorganic filler polyethylene, polyfluoroethylene or silica may be added to the surface layer. The ratio of the lubricant to the binder resin is preferably 0.1 to 50%, more preferably 1 to 30%. Further, if necessary, additives such as dispersing aid, silicone oil, leveling agent, metal soap, silane coupling agent and the like can be added.

A surface protection layer for the purpose of surface protection can be provided as required.

The coating method applied in the present invention includes a dipping coating method, a spray coating method, and a coating method.
A luco-coating method, a gravure coating method and the like can be mentioned.

The electrophotographic photosensitive member of the present invention can be
Although it can be applied to general electrophotographic devices such as printers, LED printers, and liquid crystal shutter printers, it is also applicable to devices such as display, recording, light printing, plate making, facsimile, etc. to which electrophotographic technology is applied. It can be widely applied.

Next, the process cartridge and the electrophotographic apparatus of the present invention will be described. FIG. 1 shows a schematic configuration of an electrophotographic apparatus having a process cartridge having an electrophotographic photosensitive member of the present invention. In FIG. 1, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is driven to rotate around an axis 2 at a predetermined peripheral speed in the direction of an arrow. In the rotation process, the photosensitive member 1 is uniformly charged at a predetermined positive or negative potential on the peripheral surface thereof by the primary charging means 3, and then the image exposure means (such as a slit exposure or a laser beam scanning exposure) is used. (See FIG. 1). Thus, an electrostatic latent image is sequentially formed on the peripheral surface of the photoconductor 1.

The formed electrostatic latent image is then transferred to developing means 5
Is transferred to the transfer material 6 from the paper supply unit (not shown) and fed between the photosensitive member 1 and the transfer means 6 in synchronization with the rotation of the photosensitive member 1. Are sequentially transferred by the transfer means 6. The transfer material 7 having undergone the image transfer is separated from the photoreceptor surface, introduced into the image fixing means 8 and subjected to image fixing, thereby being printed out as a copy (copy) outside the apparatus. The surface of the photoreceptor 1 after the image transfer is cleaned and cleaned by removing the transfer residual toner by the cleaning means 9, and further subjected to a static elimination process by the pre-exposure light 10 from the pre-exposure means (not shown). After that, it is repeatedly used for image formation. When the primary charging means 3 is a contact charging means using a charging roller or the like, pre-exposure is not necessarily required.

In the present invention, a plurality of components, such as the photoreceptor 1, the primary charging means 3, the developing means 5 and the cleaning means 9, are integrally connected as a process cartridge. Alternatively, the process cartridge may be configured to be detachable from a main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. For example, at least one of the primary charging means 3, the developing means 5 and the cleaning means 9 is integrally supported together with the photoreceptor 1 to form a cartridge, and the apparatus main body is guided by a guide means such as the rail 12 of the apparatus main body. The process cartridge 11 can be detachably mounted on the cartridge. When the electrophotographic apparatus is a copier or a printer, the image exposure light 4 uses reflected light or transmitted light from the original, or reads the original with a sensor and converts it into a signal. This is light emitted by scanning of the laser beam, driving of the LED array, driving of the liquid crystal shutter array, and the like.

[0039]

【Example】

Example 1 A diffraction angle 2θ ± 0.2 ° in CuKα X-ray diffraction of 9 was placed on an aluminum cylinder having an alumite-processed layer of 8 μm and sealed by nickel acetate treatment and having an outer diameter of 24 mm and a length of 257 mm. 0.0 °, 14.2 °, 23.
10.8 parts of TiOPc crystal having a strong peak at 9 ° and 27.1 ° and 1.2 parts of azoxy pigment having the following structural formula

Embedded image To polyvinyl butyral (trade name ESLEC BX-1,
10 parts of Sekisui Chemical Co., Ltd.) was added to a solution of 250 parts of cyclohexanone, dispersed in a sand mill using a 1 mmφ glass bead, and a dispersion diluted with ethyl acetate was applied. For 10 minutes to form a charge generation layer having a thickness of 0.25 μm.

Further, bisphenol Z-type polycarbonate
10 parts of a charge transport material having the following structural formula

Embedded image Was dissolved in 80 parts of methylene chloride, and the obtained solution was applied onto the charge generation layer by dip coating, dried at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 24 μm. Created body.

The prepared electrophotographic photosensitive member was evaluated by the following method.

The image was evaluated using a laser beam printer (trade name: Laser Jet IV) manufactured by Hewlett Packard. A ghost image was initially taken at a high temperature and high humidity of 35 ° C and a humidity of 85%, and a ghost image of the initial and after 2,000 sheets of durability was similarly obtained at a low temperature and a low humidity of 15 ° C and a humidity of 10%. . For the ghost image, an appropriate pattern was printed for one rotation of the drum, and then the entire image was made a halftone image.

The image evaluation was performed as follows. The endurance pattern was printed with a line of about 2 mm width every 7 mm in length and width. The image sample is an image of the entire surface black and dot density of 1 dot 1 space, developed by machine, F5 (center value)
And F9 (concentration is low). Evaluation,
If the ghost is not visible, rank 5 is set. If the ghost is visible with 1 dot 1 space F9, the rank is 4 and 1 dot 1 space.
In the case of F3, those which can be seen with F3 are ranked as 3, those which can be seen entirely with black F9 are in the rank of 2, and those which can be seen in all of them are in the rank of 1.

Further, under the above-mentioned high-temperature and high-humidity conditions and low-temperature and low-humidity conditions, the dark portion potential (V _D ) at the initial stage and after 2,000 sheets have been run.
And the light potential ( _VL ) were measured.

The evaluation results are shown in Tables 1, 2 and 3.

Example 2 In the formation of the charge generation layer in Example 1, TiOP
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1, except that c was 10 parts and azoxy pigment was 2 parts. The results are shown in Tables 1, 2 and 3.

Example 3 In the formation of the charge generation layer in Example 1, TiOP
Example 1 except that c was 6 parts and azoxy pigment was 6 parts.
An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above. The results are shown in Tables 1, 2 and 3.

Example 4 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the azo pigment contained in the charge generation layer was replaced with an azo pigment having the following structural formula. The results are shown in Tables 1, 2 and 3.

Embedded image

Example 5 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 4 except that 10 parts of TiOPc and 2 parts of an azo pigment contained in the charge generation layer were used. The results are shown in Tables 1, 2 and 3.

Example 6 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 4 except that 6 parts of TiOPc and 6 parts of an azo pigment were used in the charge generation layer. Table 1 shows the results.
2 and 3.

Example 7 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the azo pigment contained in the charge generation layer was changed to an azo pigment having the following structural formula. The results are shown in Tables 1, 2 and 3.

Embedded image

Example 8 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 7, except that 10 parts of TiOPc and 2 parts of an azo pigment contained in the charge generation layer were used. The results are shown in Tables 1, 2 and 3.

Example 9 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 7, except that 6 parts of TiOPc and 6 parts of an azo pigment contained in the charge generation layer were used. Table 1 shows the results.
2 and 3.

Examples 10 and 11 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1, except that the thickness of the alumite-processed layer was changed to 3 μm and 10 μm. The results are shown in Tables 1, 2 and 3.

Examples 12 to 14 Electrophotographic photosensitive members were prepared and evaluated in the same manner as in Examples 1, 10 and 11 except that no sealing treatment was performed. The results are shown in Tables 1, 2 and 3.
Shown in

Comparative Example 1 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that a cylinder not subjected to alumite treatment was used. The results are shown in Tables 1, 2 and 3.

Comparative Example 2 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that only the TiOPc was used as the charge generating material contained in the charge generating layer. The results are shown in Tables 1, 2 and 3.

Comparative Example 3 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the azo pigment contained in the charge generation layer was a perylene compound having the following structural formula. The results are shown in Tables 1, 2 and 3.

Embedded image

Comparative Example 4 The procedure of Example 1 was repeated except that the azo pigment contained in the charge generation layer was changed to an ancesthrone compound having the following structural formula.
An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above. The results are shown in Tables 1, 2 and 3.

Embedded image

[0059]

[Table 1]

[Table 2]

[Table 3]

[0060]

The electrophotographic photoreceptor of the present invention has high sensitivity,
In addition, there is a remarkable effect that there are few potential fluctuations and image defects. The same remarkable effects can be obtained in a process cartridge and an electrophotographic apparatus using the same.

[Brief description of the drawings]

FIG. 1 is a process car having an electrophotographic photoreceptor of the present invention.
FIG. 2 is a diagram illustrating a schematic configuration of an electrophotographic apparatus having a cartridge.

FIG. 2 is a diagram showing an example of a facsimile block having the electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor of the present invention 2 axis 3 Primary charging means 4 Image exposure light 5 Developing means 6 Transfer means 7 Transfer material 8 Image fixing means 9 Cleaning means 10 Pre-exposure light 11 Process cartridge 12 Rail 13 Image reading unit 14 Controller 15 Receiving circuit 16 Transmitting circuit 17 Telephone 18 Line 19 Image memory 20 CPU 21 Printer controller 22 Printer

Continuation of the front page (51) Int.Cl. ⁶ Identification code FI G03G 5/06 371 G03G 5/06 371 5/14 101 5/14 101B (72) Inventor Kunihiko Sekido 3-30-2 Shimomaruko, Ota-ku, Tokyo No. Inside Canon Inc.

Claims (8)

[Claims] 1. An electrophotographic photoreceptor, wherein the support is an alumite-treated aluminum cylinder, and the photosensitive layer simultaneously contains phthalocyanine and an azo pigment. 2. The phthalocyanine of claim 1 having a diffraction angle of at least 27.1 ° in CuKα characteristic X-ray diffraction.
2. The electrophotographic photoreceptor according to claim 1, wherein the photoreceptor is oxytitanium phthalocyanine having a main peak at ± 0.2 [theta]. 3. The oxytitanium phthalocyanine according to claim 2 has a diffraction angle of 2θ in CuKα characteristic X-ray diffraction.
± 0.2 ° is 9.0 °, 14.2 °, 23.9 ° and 2
3. The electrophotographic photosensitive member according to claim 2, which has a strong peak at 7.1 °. 4. The electrophotographic photosensitive member according to claim 1, wherein the azo pigment according to claim 1 is selected from the group consisting of azo pigments having a central skeleton represented by the following general formulas (1) to (4). General formula (1) General formula (2) General formula (3) General formula (4) Ar, Ar ′ and Ar ″ in the general formulas (1) to (4)
Represents a coupler residue. 5. The electrophotographic photosensitive member according to claim 1, wherein the thickness of the alumite layer of the support according to claim 1 is 1 to 15 μm. 6. The electrophotographic photosensitive member according to claim 1, wherein the alumite layer of the support according to claim 1 is subjected to a sealing treatment. 7. The electrophotographic photoreceptor and at least one means selected from the group consisting of a charging means, a developing means and a cleaning means are integrally supported, and are detachably attached to an electrophotographic apparatus main body. Process cartridge. 8. An electrophotographic apparatus comprising the electrophotographic photosensitive member, a charging unit, an image exposing unit, a developing unit, and a transfer unit.