JPH06295074A - Electrophotographic sensitive body, electrophotographic device and facsimile equipped with the electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve mechanical durability and productivity by incorporating specified polyvinylacetal into a charge producing layer and specified polycarbonate into a charge transfer layer. CONSTITUTION:This electrophptographic sensitive body has a laminated photosensitive layer consisting of at least a charge producing layer and a charge transfer layer on a conductive supporting body. The charge producing layer contains polyvinylacetal having the structure expressed by formula I, and the charge transfer layer contains polycarbonate expressed by formula II. In formula, R1R5 are hydrogen atoms, fluorine atoms, or trifluoromethyl groups, and may be same or different. However, all of R1-R6 are not hydrogen atoms. N is 500-5000 and R6-R13 are hydrogen atoms, halogen atoms or alkyl groups.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, an electrophotographic apparatus equipped with the electrophotographic photosensitive member and a facsimile, and more specifically, an electrophotographic photosensitive member having a laminated photosensitive layer containing a resin having a specific structure. The present invention relates to an electrophotographic apparatus and a facsimile equipped with the electrophotographic photosensitive member.

[0002]

2. Description of the Related Art Up to now, most electrophotographic photoreceptors using an organic photoconductive substance are used when a charge generating substance having a relatively low molecular weight such as an azo pigment or a phthalocyanine pigment is dispersed in an appropriate binder resin. There are many. Among them, a so-called layered photoreceptor, in which a photosensitive layer is functionally separated into a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance, is so-called in terms of sensitivity, potential characteristics and durability. Because it ’s good,
Currently, it is the mainstream of organic electrophotographic photoreceptors.

In the laminated type photoreceptor, carrier generation efficiency and carrier transport efficiency of the photosensitive layer, carrier injection efficiency from the charge generation layer to the charge transport layer and the like are important factors that determine the characteristics of the photoreceptor. The charge generation layer is basically composed of a charge generation substance and a binder resin.
It has a great influence on the potential characteristics and durability.

On the other hand, the charge transporting layer generally has a poor film-forming property with respect to the charge transporting material, so that a binder resin is used together to form a uniform film. Therefore, also in the charge transport layer, the characteristics of the binder resin have a significant influence on the carrier transport efficiency and the carrier injection efficiency as in the charge generation layer. Further, in a laminated type photoreceptor in which a charge transporting layer is provided on the charge generating layer, the binder resin largely bears mechanical durability.

Further, it is important to efficiently inject the carriers generated in the charge generation layer into the charge transport layer in order to improve the sensitivity. If the combination of the charge generation layer and the charge transport layer is not good, not only high sensitivity cannot be achieved, but also adverse effects such as increase in residual potential and memory, environmental dependency and potential fluctuation are recognized.

Polycarbonate generally has good transparency,
It has been proposed as a binder resin for a charge transport layer because of its properties such as good compatibility with a charge transport material, electrical insulation, high withstand voltage, mechanical durability and good abrasion resistance. However, the polycarbonate A represented by the following structural formula, which is a typical example of the polycarbonate, has the following drawbacks.

[Chemical 3]

(1) The solubility of the resin is poor and it shows good solubility in a solvent of halogenated aliphatic hydrocarbons such as dichloromethane and 1,2-dichloroethane, but these halogenated aliphatic hydrocarbons are Due to its low boiling point, the coated surface is likely to be whitened when a photoconductor is manufactured using a coating liquid prepared from these solvents. (2) Although it is partially soluble in tetrahydrofuran, 1,4-dioxane, cyclohexanone, and mixed solvents of these in solvents other than halogenated aliphatic hydrocarbons, the stability of the solution is poor and the photoreceptor Is not suitable for manufacturing. (3) The adhesiveness of the coating film is poor, and cracks are likely to occur from the interface. Therefore, Polycarbonate A
It is difficult to obtain satisfactory properties by using as a binder resin for the charge transport layer.

[0008]

The object of the present invention is to provide an electrophotographic photoreceptor having higher sensitivity by using a specific resin as a binder resin for the charge generation layer and the charge transport layer, and to repeatedly use the resin. To provide a stable electrophotographic photosensitive member, to provide an electrophotographic photosensitive member excellent in mechanical durability and productivity, and to provide an electrophotographic apparatus and a facsimile equipped with the electrophotographic photosensitive member. Is to provide.

[0009]

The present invention relates to an electrophotographic photosensitive member having a laminate type photosensitive layer having at least a charge generating layer and a charge transporting layer on a conductive support, and the charge generating layer is represented by the following general formula (1). And a charge transport layer containing the polycarbonate represented by the following general formula (2).

[Chemical 4] In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are hydrogen atoms,
It represents a fluorine atom or a trifluoromethyl group, which may be the same or different. However,
Excluding the case where R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are all hydrogen atoms.

[Chemical 5] In the formula, n represents 500 to 5,000, and R ₆ , R ₇ , and R
₈ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ represent a hydrogen atom, a halogen atom or an alkyl group.

The polyvinyl acetal represented by the general formula (1) has a weight average molecular weight of 10,000 to 1,000,0.
Range of 00, especially 100,000 to 500,000
It is preferably in the range of. The degree of acetalization is preferably 50 mol% or more, and particularly preferably 70 to 90 mol%. Further, the saponification degree of polyvinyl alcohol, which is a raw material of the polyvinyl acetal, is preferably 85% or more.

In the general formula (2) showing the polycarbonate Z, R ₆ , R ₇ , R ₈ , R ₉ , R ₁₀ and R
_The halogen atom represented by ₁₁ , R ₁₂ and R ₁₃ includes a fluorine atom, a chlorine atom, a bromine atom and the like, and the alkyl group includes a methyl group, an ethyl group and the like.

Representative examples of polyvinyl acetal represented by the general formula (1) are shown in Tables 1 and 2 for the acetal structure portion. However, the resin is not limited to the exemplified resins below.

[Table 1]

[Table 2]

Synthesis Example of Polyvinyl Acetal of Resin Example 1 60 ml of 1,2-dichloroethane was placed in a flask, and polyvinyl alcohol (polymerization degree 1,000, saponification degree 98.5%, manufactured by Co., Ltd.) After adding 3.5 g of Kuraray) and 20 g of p-fluorobenzaldehyde, concentrated hydrochloric acid of 0.
6 ml was added dropwise, and the mixture was heated with stirring at 40 to 45 ° C. for about 8 hours. After the reaction, the reaction solution was added dropwise to a solution prepared by dissolving 0.3 g of sodium hydroxide in 2 liters of methanol. The precipitated resin was filtered off and 1,2-dichloroethane 1
The resin was dissolved in 00 ml and dropped into 2 liter of methanol again to precipitate the resin. The precipitated resin was separated by filtration and dried under reduced pressure to obtain 6.1 g of polyvinyl acetal of Resin Example 1 which was a white cotton-like resin. When the degree of acetalization of this resin was measured according to the method described in Japanese Industrial Standard K6728 (polyvinyl butyral test method), the degree of acetalization was 81%.

Other polyvinyl acetals represented by the general formula (1) can be synthesized in the same manner as above.

Table 3 shows typical examples of the polycarbonate Z represented by the general formula (2). However, the resin is not limited to the exemplified resins below.

[Table 3]

The polyvinyl acetal represented by the general formula (1) is preferably contained in the charge generation layer in an amount of 10 to 90% by weight, particularly 20 to 50% by weight.

Further, the polyvinyl acetal represented by the general formula (1) may be used as a binder resin for the charge generation layer together with other resins in a ratio that does not impair the object of the present invention. Other resins include polyvinyl butyral, polyvinyl benzal, polyarylate, polycarbonate.
Resins such as polyester, phenoxy resin, acrylic resin, polyamide, polyurethane, polystyrene and acrylonitrile-styrene copolymer, or
Examples thereof include organic conductive polymers such as poly-N-vinyl carbazole and polyvinyl anthracene.

Examples of the charge generating substance include azo pigments such as monoazo, disazo and trisazo, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, indigo pigments such as indigo and thioindigo, perylene acid anhydride and perylene imide. Perylene pigments, polycyclic quinone pigments such as anthanthrone and pyrenequinone, squarylium pigments, pyrylium, thiopyrylium salts, triphenylmethane pigments and the like.

Polycarbonate Z represented by the general formula (2) retains the mechanical durability of the polycarbonate and has good solubility in various solvents, and a solution thereof. Is stable against changes over time and contributes to improved productivity and quality. Further, the polycarbonate Z may be used as a binder resin for the charge transport layer together with other resins in such a ratio that the object of the present invention is not impaired. Other resins include polyvinyl butyral, polyvinyl benzal, polyarylate, polycarbonate,
Examples thereof include resins such as polyester, phenoxy resin, acrylic resin, polyamide, polyurethane, polystyrene, and acrylonitrile-styrene copolymer, and organic conductive polymers such as poly-N-vinylcarbazole and polyvinylanthracene.

The charge transport material includes an electron transport material and a hole transport material. Examples of the electron transport material include 2,4,7-
There are electron-accepting substances such as trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, chloranil, and tetracyanoquinodimethane, and polymers obtained by polymerizing these electron-accepting substances.

Examples of the hole-transporting substance include polycyclic aromatic compounds such as pyrene and anthracene, carbazole and indole.
, Imidazole, oxazole, thiazole, oxadiazol, pyrazol, pyrazoline, thiadiazole
Heterocyclic compounds such as phenol and triazole, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, N, N-diphenylhydrazino-3-methylden-
Hydrazone compounds such as 9-ethylcarbazol, α
-Styryl compounds such as -phenyl-4'-N, N-diphenylaminostilbene, 5- [4- (di-p-tolylamino) benzylidene] -5H-dibenzo [a, d] dichloroheptene, benzidine compounds, triary-
Polymer having a methane compound, triphenylamine or a group consisting of these compounds in the main chain or side chain
(For example, poly-N-vinylcarbazol, polyvinyl anthracene, etc.) can be mentioned.

As the solvent, tetrahydrofuran, 1,4
-Ethers such as dioxane, ketones such as cyclohexanone and methyl ethyl ketone, esters such as ethyl acetate and butyl acetate, aromatics such as toluene, xylene and monochlorobenzene, alcohols such as methanol and ethanol And aliphatic halogenated hydrocarbons such as chloroform and methylene chloride, and amides such as N, N-dimethylformamide.

The charge generating layer is formed by dissolving the charge generating substance together with the specific resin in a solvent and applying the resulting coating liquid for the charge generating layer to a film thickness of 5 μm or less.
Particularly, 0.01 to 1 μm is preferable. The charge transport layer is laminated on or under the charge generation layer and has a function of receiving carriers from the charge generation layer and transporting the carriers in the presence of an electric field. The charge transport layer is formed by dissolving the charge transport substance in a solvent together with the specific resin and applying the solution, and the film thickness is preferably 5 to 40 μm, and particularly preferably 15 to 30 μm.

As the conductive support, for example, aluminum, aluminum alloy, copper, zinc, stainless steel, titanium, nickel, indium, gold or platinum is used. Also, plastics (for example, polyethylene, polypropylene, polyvinyl chloride and polyethylene terephthalate, acrylic resin, etc.) and conductive particles (for example, carbon) formed by coating the above metal or alloy by a vacuum deposition method.
And a support in which conductive particles are impregnated in plastic or paper, and the like.

An undercoat layer having a barrier function and an adhesive function can be provided between the conductive layer and the photosensitive layer. The undercoat layer is casein, polyvinyl alcohol, nitrocellulose
And nylon (nylon 6, nylon 66, nylon 610, copolymer nylon, alkoxymethylated nylon, etc.), polyurethane, aluminum oxide and the like. The film thickness is 5 μm or less, especially 0.1 to 3 μm
Is preferred.

Further, a resin layer or a resin layer containing conductive particles may be laminated as a protective layer on the photosensitive layer.

The above-mentioned various layers can be applied by, for example, a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method, a beam coating method. -It can be performed by any coating method such as a towing method.

The reason why the electrophotographic photosensitive member of the present invention exhibits high sensitivity is that the energy barrier between the charge generation layer and the charge transport layer is small, which is advantageous for carrier injection, and that carriers inside the charge transport layer are advantageous. This may be because the mobility is high.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines but also in laser beam printers, C
RT printer, LED printer, liquid crystal printer,
It can be widely used in electrophotographic application fields such as laser plate making and facsimile.

The present invention also comprises an electrophotographic apparatus provided with the electrophotographic photosensitive member of the present invention.

The present invention also comprises an electrophotographic apparatus equipped with the electrophotographic photosensitive member of the present invention and a facsimile having a receiving means for receiving image information from a remote terminal.

Next, an electrophotographic apparatus and a facsimile equipped with the electrophotographic photosensitive member of the present invention will be described. Figure 1
The schematic structure of a general transfer type electrophotographic apparatus using the drum type photoreceptor of the present invention is shown in FIG. In the figure, reference numeral 1 denotes a drum type photosensitive member as an image bearing member, which is rotationally driven around a shaft 1a in a direction of an arrow at a predetermined peripheral speed. The photosensitive member 1 is uniformly charged at its peripheral surface by a charging unit 2 at a predetermined positive or negative potential in the course of its rotation, and then at an exposure unit 3 an optical image exposure L (slit exposure Laser
Beam scanning exposure). As a result, electrostatic latent images corresponding to the exposed image are sequentially formed on the peripheral surface of the photoconductor. The electrostatic latent image is then toner-developed by the developing means 4, and the toner-developed image is rotated by the transfer means 5 from a paper feeding portion (not shown) between the photosensitive body 1 and the transfer means 5. Then, the image is sequentially transferred onto the surface of the transfer material P that is fed in synchronization with the above. The transfer material P which has received the image transfer is separated from the surface of the photoconductor and is introduced into the image fixing means 8 where it is subjected to image fixing and printed out as a copy (copy). The surface of the photoreceptor 1 after the image transfer is transferred by the cleaning means 6 to the toner after transfer.
Is removed, the surface is cleaned, the charge is removed by the pre-exposure means 7, and the surface is repeatedly used for image formation. Photoconductor 1
A corona charging device is generally widely used as the uniform charging means 2. Also, as the transfer device 5, corona transfer means is generally widely used. As an electrophotographic apparatus, a plurality of constituent elements such as the above-mentioned photoconductor, developing means, and cleaning means are integrally combined and configured as an apparatus unit, and this unit is detachably attached to the apparatus main body. It may be configured. For example, the photoconductor 1 and the cleaning means 6 may be integrated into one device unit, and the device body may be detachably configured by using guide means such as a rail. At this time, the above-mentioned apparatus unit may be configured with a charging means and / or a developing means. Further, the light image exposure L is used for electrophotographic devices such as copying machines and printers.
When used as a light source, the reflected light or the transmitted light from the original is used, or when the original is read and converted into a signal, the laser beam is scanned by this signal, the light emitting diode array is driven, or the liquid crystal shutter is used. -It is performed by driving the array or the like. Further, when used as a printer of a facsimile, the light image exposure L becomes an exposure for printing the reception data.

FIG. 2 is a block diagram showing an example of this case. The controller 10 controls the image reading unit 9 and the printer 18. The entire controller 10 is C
It is controlled by the PU 16. The read data from the image reading unit is transmitted to the partner station through the transmission circuit 12. The data received from the partner station is sent to the printer 18 through the receiving circuit 11. Predetermined image data is stored in the image memory. The printer controller 17 controls the printer 18. 13 is a telephone. Line 14
The image (image information from the remote terminal connected via the line) received from the demodulator is demodulated by the receiving circuit 11, and then the CPU 16 performs signal processing of the image information and sequentially stores it in the image memory 15. . When at least one page of image is stored in the memory 15, the image of that page is stored. The CPU 16 reads out one page of image information from the memory 15 and sends the one page of image information signaled to the printer controller 17. Upon receiving the image information of one page from the CPU 16, the printer controller 17 controls the printer 18 to record the image information of the page. The CPU 16 is a printer
While recording by 18, the next page is being received.
The image is received and recorded as described above.

[0033]

【Example】

Example 1 A φ30 mm × 346 mm aluminum cylinder was prepared as a conductive support. Next, 10 g of alcohol-soluble copolymerized nylon (number average molecular weight 29,000) and methoxymethylated nylon (number average molecular weight 32,000).
5 g was dissolved in 95 g of methanol, and the coating liquid was applied onto the aluminum cylinder by dip coating to form an undercoat layer of 0.5 μm.

Next, 10 parts of a disazo pigment having the following structural formula,

[Chemical 6] Polyvinyl acetal of Resin Example 1 (number average molecular weight 60,
000) and 5 parts of cyclohexane were dispersed in a sand mill for 20 hours. This dispersion was diluted with methyl ethyl ketone to prepare a coating solution for the charge generation layer. This coating liquid was applied on the undercoat layer to form a charge generation layer having a thickness of 0.2 μm.

Next, 10 parts of the polycarbonate Z of Resin Example 13 and 10 parts of the triarylamine compound having the following structural formula were added.

[Chemical 7] This coating solution was dissolved in 70 parts of monochlorobenzene and applied on the charge generation layer to form a 20 μm charge transport layer.

The produced electrophotographic photosensitive member is manufactured by Canon Inc.
It was attached to a copying machine NP2020 and evaluated for electrophotographic characteristics. The electrophotographic characteristic was evaluated by setting the dark potential (V _D ) to -70.
The potential (V _L ) when set to 0 V and exposed to 1.0 lux · second, and the potential change after repeated use 10,000 times were measured. The results are shown in Table 4. The image sample after repeated use 10,000 times was also clear.

Examples 2 to 12, except that the polyvinyl acetals of Resin Examples 2 to 12 were used as the binder resin for the charge generation layer and Resin Examples 13 to 18 were used as the binder resin for the charge transport layer, Electrophotographic photoreceptors of Examples 2 to 12 were prepared in the same manner as in Example 1 and electrophotographic characteristics were evaluated by the same method as in Example 1. The results are shown in Table 4.
Shown in.

[Table 4]

Comparative Example 1 Example 1 was repeated except that a butyral resin (trade name S-REC BL-S, manufactured by Sekisui Chemical Co., Ltd.) was used in place of the polyvinyl acetal of Resin Example 1 of Example 1. An electrophotographic photosensitive member was prepared in the same manner as in 1. and the electrophotographic characteristics were evaluated by the same method as in Example 1. The results are shown in Table 5.

[Table 5]

Comparative Example 2 Polycarbonate A (trade name: Panlite L = 1250, manufactured by Teijin Kasei Co., Ltd.) was used in place of polycarbonate Z when forming the charge transport layer, and dioxane was used as a solvent. The other is
An electrophotographic photosensitive member was prepared in the same manner as in Example 1, and the electrophotographic characteristics were evaluated by the same method as in Example 1. The results are shown in Table 4. Although the electrophotographic characteristics were not significantly different from those in Example 1, the solution for coating the charge transport layer using polycarbonate A had a solution viscosity increased to 3 to 4 times after 24 hours, and further longer. When left for a time, it gelled and lost its fluidity. On the other hand, the solution for coating the charge transport layer using polycarbonate Z was stable even after 3 months, and a large difference was observed in the stability of the solutions. A marked advantage was also found in the production of electrophotographic photoreceptors.

Comparative Examples 3 to 5 Electrons of Comparative Examples 3 to 5 were prepared in the same manner as in Example 1 except that the following resin was used in place of the polycarbonate Z when forming the charge transport layer of Example 1. A photographic photoreceptor was created. Comparative Example 3: Acrylic-styrene copolymer (trade name: Estyrene-200, manufactured by Nippon Steel Chemical Co., Ltd.) Comparative Example 4: Polystyrene (trade name: Styron 470, manufactured by Asahi Kasei Co., Ltd.) Comparative Example 5: Polyester (trade name) Byron 200, Toyobo Co., Ltd.

The prepared electrophotographic photoreceptors of Comparative Examples 3 to 5 were placed in a copying machine having the same process as that of Example 1 and a durability test was conducted. He had many scars. Also, the potential characteristics were deteriorated due to the abrasion of the surface of the photoconductor after about 3,000 times durability, and the image sample was fogged.

[0042]

INDUSTRIAL APPLICABILITY The electrophotographic photosensitive member of the present invention has a remarkable effect that it has excellent properties not only in initial characteristics but also in durability, and in electrophotographic apparatuses and facsimiles equipped with the electrophotographic photosensitive member. Also has the above-mentioned remarkable effect.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a general transfer type electrophotographic apparatus.

FIG. 2 is a block diagram of a facsimile using the electrophotographic apparatus as a printer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Drum type photoconductor as an image carrier (electrophotographic photoconductor of the present invention) 2 Corona charging device 3 Exposure part 4 Developing means 5 Transfer means 6 Cleaning means 7 Pre-exposure means 8 Image fixing means L Optical image exposure P Transfer material that received image transfer 9 Image reading unit 10 Controller 11 Receiver circuit 12 Transmitter circuit 13 Telephone 14 Line 15 Image memory 16 CPU 17 Printer controller 18 Printer-

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satomi Omura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (3)

[Claims] 1. An electrophotographic photoreceptor having a laminate type photosensitive layer having at least a charge generating layer and a charge transporting layer on a conductive support, wherein the charge generating layer has a structure represented by the following general formula (1). An electrophotographic photoconductor containing CETAL and the charge transport layer containing a polycarbonate Z represented by the following general formula (2). [Chemical 1] In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are hydrogen atoms,
It represents a fluorine atom or a trifluoromethyl group, which may be the same or different. However,
Excluding the case where R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are all hydrogen atoms. [Chemical 2] In the formula, n represents 500 to 5,000, and R ₆ , R ₇ , and R
₈ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ represent a hydrogen atom, a halogen atom or an alkyl group. 2. An electrophotographic apparatus provided with the electrophotographic photosensitive member according to claim 1. 3. A facsimile having an electrophotographic apparatus equipped with the electrophotographic photosensitive member according to claim 1 and means for receiving image information from a remote terminal. [0001]