JPH0540358A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body excellent in scratching resistance and wear resistance. CONSTITUTION:This photosensitive body has a photosensitive layer formed on a conductive supporting body. The surface layer of this photosensitive body is formed by polymn. of a compd. expressed by at least formula I. Thereby, the obtd. electrophotographic sensitive body has excellent scratching resistance and wear resistance and high durability, so that high-quality picture characteristics can be maintained without reduction of dark potential or fogging after long-term use. In the formula, R is -CH2-CH-O-CH2 X is an aryl group, alkyl group, cyclic alkyl group, or heterocyclic group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoconductor, and more particularly to a highly durable electrophotographic photoconductor having high surface hardness and excellent wear resistance. It is possible to increase the running cost and reduce the running cost.

[0002]

2. Description of the Related Art An electrophotographic photosensitive member is a main medium for forming an image in an electrophotographic process such as a copying machine or a laser beam printer. The imaging process involves charging,
It consists of a repeating process of exposure, development, cleaning, and static elimination. More specifically, when an electrophotographic photoreceptor uniformly charged by a corona electrode or a rubber electrode is exposed to a light image using halogen light or laser light, the charging potential of the exposed portion is attenuated and an electrostatic latent image is formed. It Next, the electrostatic latent image is developed using a developer called toner composed of charged fine particles to form a visible image on the electrophotographic photosensitive member. The visible image is transferred onto the transfer material by Coulomb force and pressure by transfer charging.
At this time, not all the toner is transferred, and the toner remains on the electrophotographic photosensitive member. Therefore, it is necessary to clean the residual toner for repeated use. After cleaning, the charge history is removed by strong exposure, bias application, etc., and then the process is repeated.

The cleaning will be described in more detail. As means for removing fine particles such as toner, fur brush, magnetic brush, blade cleaning, etc. are known. In particular, blade cleaning is the most frequently used cleaning method because of its high cleaning accuracy and its simple device configuration. The blade cleaning is configured so that an elastic member made of polyurethane or the like and supported by a sheet metal is pressed and abutted in the generatrix direction of the photoconductor. The direction of contact of the blade is
The relationship with the photoconductor is in the forward direction and in the counter direction. From the viewpoint of cleaning accuracy, the latter counter type cleaning is more preferable. further,
In order to improve the cleaning accuracy, it is advisable to increase the contact pressure of the blade with the photoconductor.

While the above-mentioned improvement of cleaning accuracy is very important for maintaining the image quality during repeated use, it has the drawback of increasing the frictional force generated between the photosensitive member and the blade. An increase in the frictional force between the two significantly reduces the life of the photoconductor due to an increase in the amount of abrasion of the photoconductor and the occurrence of scratches.

Particularly, in recent years, in organic photoconductors whose use amount is rapidly increasing due to their advantages such as mass productivity, low cost and pollution-free property, the surface mechanical strength is not sufficient and durability is extremely poor. It was a thing. The biggest reason is that the organic binder forming the photosensitive layer in the organic photoreceptor does not have sufficient mechanical strength. That is, since an organic photoconductive compound having photoconductor characteristics rarely has sufficient film-forming property by itself, it is necessary to use it by being compatible or dispersed in an organic binder to form a film as a photoconductor. there were. Especially, the loss of photoreceptor characteristics is small
Although it is a solvent-soluble thermoplastic binder, no binder having excellent mechanical strength has hitherto been available.

[0006]

On the other hand, attempts have been made to obtain a photosensitive layer having a high hardness after a polymerization process using polymerizable monomers and oligomers. Specifically, JP-A-55
-85058, 61-41152, 61-20146
1, 62-2014460, JP-A-1-116655.
It is disclosed in Japanese Unexamined Patent Publication No. 3,1-134364, 1-134365.

However, the compatibility and dispersibility of the photoconductive compound with the monomers and oligomers, as well as the polymerization product, were not good. In addition, the photoconductive compound is often subject to reaction deterioration during the polymerization reaction, and the photoconductor characteristics were not satisfied.

Therefore, the present invention provides an organic photoreceptor using an organic photoconductive compound, which has a surface of high hardness formed by polymerizing a specific polysynthetic monomer, and has a high durability, which is excellent in scratch resistance and abrasion resistance. It aims at providing an electrophotographic photosensitive member.

[0009]

That is, the present invention provides an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the surface layer of the photosensitive member is at least a compound represented by the following formula (1). An electrophotographic photosensitive member, which is a layer formed by polymerization,

[0010]

[Chemical 2] Hereinafter, the present invention will be described in detail.

In the formula (1), the aryl group represented by X includes an aryl ether group, an aryl thioether group, a group consisting of two aryl groups bonded by a bond or a divalent hydrocarbon group, and the like. Be done.

[0012]

[Chemical 3] Although a curing agent or an initiator is used to polymerize the monomer of the present invention, since the functional density of the monomer is high and the reaction rate is fast, the polymerization can be performed under mild conditions. Therefore, the photoconductive material is less likely to be deteriorated by the polymerization reaction as in the conventional case. Further, since the functional group density is high, the hardness of the polymer is high and a surface layer having excellent durability can be obtained. Further, it has excellent compatibility and dispersibility with the photoconductive material.

As the curing agent and the initiator, Lewis acid salts, amines, polyamides, thiols, phenols, acid anhydrides and the like are used. Of these, the Lewis acid salt and the tertiary amine (Lewis base) are polymerized as a homopolymer of the monomer of the present invention, and other than that, a curing agent is partially contained in the polymer.

As the Lewis acid salt,

[0015]

[Chemical 4] And a salt of an amine, aryldiazonium, arylhalonium, triphenylsulfonium, iron-arene, or the like, or a complex thereof is used.

Polymerization is initiated by heat or light irradiation.
In particular, some Lewis acid salts generate cations by light irradiation to initiate polymerization.

As the light source for generating photoions, the most suitable one is selected according to the kind of photoinitiator, but it is a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, an electrodeless lamp, a xenon lamp, an excimer laser, He.
-A Cd laser or the like is used.

The monomer of the present invention can be polymerized after mixing with another polymerizable monomer or oligomer, and further with another polymer binder. Polymer binders that can be mixed (including those obtained by polymerizing thermoplastic resins and the above-mentioned polymerizable monomers and oligomers) are polyester, polyurethane, polyacrylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, polyamideimide. ,
Phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, melamine resin, nylon, polysulfone, polyallyl ether, polyacetal, butyral resin, fluorine resin and the like. In particular, acrylate, methacrylate, and epoxy-based polymerizable monomers and oligomers have excellent compatibility and are convenient for forming a mixed system.

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

In the present invention, the photosensitive layer may have either a single layer structure or a laminated structure. In a single-layer photosensitive layer, photocarriers are generated and moved in the same layer, and the photosensitive layer itself becomes a surface layer. On the other hand, the laminated photosensitive layer has a structure in which a charge generation layer that generates photocarriers and a charge transport layer that moves the generated carriers are stacked. Either the charge generation layer or the charge transport layer may be the surface side layer of the laminated photosensitive layer. Further, in either case of a single layer or a laminated layer, it is possible to provide a protective layer on the photosensitive layer,
In this case, the protective layer serves as the surface layer. In any of the cases of the present invention, the surface layer contains a polymerization product of the monomer of the present invention to form a surface layer having high hardness and excellent wear resistance.

The thickness of the single-layer photosensitive layer is preferably 8 to 40 μm, more preferably 12 to 30 μm. A photoconductive material such as a charge generating material or a charge transporting material is preferably 20 to
The content is 80% by weight, more preferably 30 to 70% by weight.

In the laminated photosensitive layer, the thickness of the charge generation layer is preferably 0.001 to 6 μm, more preferably
It is 0.01 to 2 μm. The amount of the charge generating material contained in the charge generating layer is preferably 10 to 100% by weight,
It is more preferably 50 to 100%. The thickness of the charge transport layer is preferably 5-70 μm, more preferably 10-3.
It is 0 μm. The amount of the charge transport material contained in the charge transport layer is preferably 20 to 80% by weight, more preferably 30 to 70%.

The charge generating material used in the present invention includes phthalocyanine pigments, polycyclic quinone pigments, trisazo pigments, disazo pigments, azo pigments, perylene pigments, indigo pigments, quinacridone pigments, azurenium salt dyes, squalium dyes, cyanine dyes, Examples thereof include pyrylium dyes, thiopyrylium dyes, xanthene dyes, quinoneimine dyes, triphenylmethane dyes, styryl dyes, selenium, selenium-tellurium alloys, amorphous silicon, and cadmium sulfide.

Examples of charge transport materials include pyrene compounds, N-alkylcarbazole compounds, hydrazone compounds, N, N-dialkylaniline compounds, diphenylamine compounds, triphenylamine compounds, triphenylmethane compounds, pyrazoline compounds, styryl compounds, Examples thereof include stilbene compounds.

When a protective layer is provided, its thickness is 0.01-.
The thickness is preferably 10 μm, more preferably 0.1 to 7 μm. The protective layer may contain a charge generating material or a charge transporting material. Furthermore, the metal and its oxide in the protective layer,
It may contain a conductive material such as a nitride, a salt, an alloy or carbon. Such metal species include iron, copper, gold, silver,
Examples thereof include lead, zinc, nickel, tin, aluminum, titanium, antimony and indium. Specifically, I
TO, TiO _2, ZnO, etc. SnO _2, Al ₂ O ₃ can be used. The conductive material is dispersed in the protective layer in the form of fine particles, and the particle size is preferably 0.001.
.About.5 .mu.m, more preferably 0.01 to 1 .mu.m, and the amount added to the protective layer is preferably 1 to 70 .mu.m.
%, More preferably 5 to 50% by weight. Titanium coupling agent, silane coupling agent, as a dispersant
Various surface active agents may be used.

When a layer other than the surface layer is formed, the polymerization product of the monomer of the present invention is not always necessary, and a film is formed with the following polymer compound. Polyester, polyurethane, polyacrylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, polyamide-imide, nylon, polysulfone, Polyallyl ether,
Examples include polyacetal and butyral resin.

The electroconductive support of the electrophotographic photoreceptor of the present invention includes iron, copper, gold, silver, aluminum, zinc, titanium,
A metal or alloy such as lead, nickel, tin, antimony or indium, or an oxide of the above metal, carbon, a conductive polymer or the like can be used. There are a drum shape such as a cylindrical shape and a cylindrical shape, and a belt shape and a sheet shape. The conductive material may be molded as it is, used as a paint, deposited, or processed by etching or plasma treatment.
In the case of paint, the support is paper, not to mention the above metals and alloys,
Plastic etc. are also used.

An undercoat layer may be provided between the conductive support and the photosensitive layer. The undercoat layer functions as charge injection control at the interface and as an adhesive layer. The undercoat layer is mainly composed of a binder resin, but may contain the above metal or alloy, or an oxide, salt or surfactant thereof. Specific examples of the binder resin forming the undercoat layer include polyester, polyurethane, polyacrylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, Examples include allyl resin, alkyd resin, polyamide-imide, nylon, polysulfone, polyallyl ether, polyacetal, butyral resin, and the like. The thickness of the undercoat layer is preferably 0.05 to 7 μm.
m, and more preferably 0.1 to 2 μm.

As the method for producing the electrophotographic photosensitive member of the present invention, methods such as vapor deposition and coating are used. The coating method can form a wide range of films from thin films to thick films with various compositions. Specifically, it is applied by a bar coater, knife coater, dip coating, spray coating, beam coating, electrostatic coating, roll coater, attritor, powder coating or the like.

FIG. 1 shows a schematic structural example of a general transfer type electrophotographic apparatus using the electrophotographic photosensitive member of the present invention. In the figure, reference numeral 1 denotes a drum type photosensitive member of the present invention as an image bearing member, which is rotationally driven around a shaft 1a in a direction of an arrow at a predetermined peripheral speed. During the rotation of the photoconductor 1, the peripheral surface of the photoconductor 1 is uniformly charged with a predetermined positive or negative potential,
Next, the exposure unit 3 receives an optical image exposure L (slit exposure, laser beam scanning exposure, etc.) by an image exposure unit (not shown). As a result, electrostatic latent images corresponding to the exposed images 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 between the photoconductor 1 and the transfer means 5 from a paper feeding portion (not shown). The images are sequentially transferred onto the surface of the transfer material P that has been synchronously taken out and fed. The transfer material P that 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 the image fixing and printed out as a copy. The surface of the photoconductor 1 after the image transfer is cleaned by the cleaning unit 6 to remove the residual toner after transfer, and is further discharged by the pre-exposure unit 7 to be repeatedly used for image formation.

As the uniform charging means 2 for the photoconductor 1, a corona charging device is generally widely used. In addition, the transfer device 5
Corona transfer means are also widely used. The electrophotographic apparatus is configured by integrally combining a plurality of components, such as the above-described photoconductor, developing unit, and cleaning unit, as an apparatus unit, and this unit is configured to be detachable from the apparatus main body. May be. For example, photoconductor 1
The cleaning means 6 and the cleaning means 6 may be integrated into one apparatus unit, and may be detachably configured by using a guide means such as a rail of the apparatus body. At this time, the above device unit may be provided with a charging unit and / or a developing unit.

When the electrophotographic apparatus is used as a copying machine or a printer, the light image exposure L is reflected light or transmitted light from an original, or an original is read and converted into a signal, and scanning of a laser beam or an LED array is performed by this signal. Drive or liquid crystal shutter array drive.

When used as a printer for a facsimile, the light image exposure L becomes an exposure for printing the received data. FIG. 2 is a block diagram showing an example of this case. The controller 11 controls the image reading unit 10 and the printer 19. The entire controller 11 is controlled by the CPU 17. The read data from the image reading unit 10 is transmitted to the partner station via the transmission circuit 13. The data received from the partner station is sent to the printer 19 through the receiving circuit 12. The image memory 16 stores predetermined image data. The printer controller 18 controls the printer 19. 14 is a telephone.

The image information received from the line 15 (image information from a remote terminal connected via the line) is demodulated by the receiving circuit 12, then decoded by the CPU 17, and sequentially stored in the image memory 16. Is stored. When the image information of at least one page is stored in the memory 16, the image recording of that page is performed. The CPU 17 reads out one page of image information from the memory 16 and sends the decoded one page of image information to the printer controller 18. When the printer controller 18 receives the image information of one page from the CPU 17, the printer controller 18 controls the printer 19 to record the image information of the page.

The CPU 17 is receiving the next page while the printer 19 is recording. As described above, the image is received and recorded.

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.

[0038]

EXAMPLES The present invention will be described below with reference to examples.

[Example-1] Nylon (M-4000,
Toray) 10 parts by weight, 100 parts by weight of methanol, and 90 parts by weight of isopropanol are mixed and dissolved, and then the outer diameter is 80
mm, wall thickness 1.5 mm, and length 365 mm, and applied by dipping onto an aluminum cylinder, dried at 90 ° C. for 20 minutes, and provided with a 2.0 μm undercoat layer.

Next, 10 parts by weight of the following trisazo pigment,

[0041]

[Chemical 5] Polycarbonate resin (bisphenol A type, Mn2
50,000) 5 parts by weight and cyclohexanone 600 parts by weight were dispersed in a sand mill to obtain a charge generation layer coating material. This paint is applied onto the undercoat layer by dip coating at 120 ° C. for 20
After drying for a minute, a charge generation layer of 0.15 μm was obtained.

Next, 20 parts by weight of the following biphenyl compound,

[0043]

[Chemical 6] 5 parts by weight of the following monomers,

[0044]

[Chemical 7] 0.1 parts by weight of the following initiator,

[0045]

[Chemical 8] And polycarbonate resin (bisphenol A type: Mw
50,000) 15 parts by weight and monochlorobenzene 300
A solution obtained by mixing parts by weight was applied onto the charge generation layer by dip coating. After drying at 100 ° C for 5 minutes, use a high-pressure mercury lamp for 12
After irradiation with UV light of 00 μJ / cm ² , 120 ° C.,
After 60 minutes of drying, a photoreceptor having a 15 μm charge transport layer was obtained.

Comparative Example-1 20 parts by weight of the biphenyl compound of Example-1, 20 parts by weight of the same polycarbonate resin (bisphenol A type: Mw 50,000) and 300 parts by weight of monochlorobenzene were mixed. This solution was applied onto the charge generation layer of Example 1 by dip coating, and dried at 120 ° C. for 60 minutes to obtain a photoreceptor having a 23 μm charge transport layer.

Example 2 10 parts by weight and 0.4 parts by weight of the monomer and photoinitiator of Example 1 were mixed with 90 parts by weight of methyl ethyl ketone, and this solution was used as a comparative example.
1 was spray coated onto the charge transport layer. Drying at 70 ° C. for 10 minutes, UV irradiation of 1200 μJ / cm ² , 120
By successively drying at 60 ° C. for 60 minutes, a photoreceptor having a protective layer of 1.2 μm was obtained.

[Comparative Example-2] A photoreceptor having a protective layer was obtained in the same manner as in Example-2 except that the following monomers were used.

[0049]

[Chemical 9] [Physical property evaluation] i) Abrasion test A sample using an aluminum sheet having a thickness of 50 μm in place of the aluminum cylinder was prepared at the same time when the photoreceptor was manufactured. This sheet sample was subjected to a wear test with a weight of 500 g × 2, 5,000 rotations using a Taber wear tester to measure the weight reduction of the sample. As a result, in Comparative Example-1, the amount was 9.6 mg, while in Example-1, the wear resistance was 2.8 mg, which was excellent. Further, due to the difference in the type of the acrylate monomer, the amount was 3.1 mg in Comparative Example-2, while it was 0.9 mg in Example-2 using the monomer of the present invention.
It showed very good wear resistance as mg.

Ii) Scratch test A scratch tester manufactured by Haydon was used to scratch the surface of the photoreceptor with a load of 50 g using a 0.5 mm diameter diamond needle, and the depth was measured. In Comparative Example-1, the scratch was 5.1 μm, while in Example-1, the scratch was 1.6 μm, and in Comparative Example-2, the scratch was 1.5 μm, whereas in Example-2. Has a scratch of 0.8 μm, indicating that the photoreceptor of the present invention has a remarkably high surface hardness.

[Evaluation of Actual Machine] A Canon copying machine {color laser copier 200 (CLC-200)} was used. A
Full-color 10,000 sheets were copied on 4 size paper, and the amount of abrasion of the photoconductor, the decrease of dark potential, and other stains (fogging) on solid white images were tested.

The results are summarized in Table 1. It is shown that the photoreceptor of the present invention has a very small abrasion amount, and there is no decrease in dark potential or fog, which is extremely excellent in durability.

[Example-3] A sample similar to Example-2 was prepared except that the following monomers were used.

[0054]

[Chemical 10] [Example-4] A sample similar to the example-2 was prepared except that the following monomers were used.

[0055]

[Chemical 11] [Example-5] Comparative Example-1 on the undercoat layer of Example-1
The charge transport layer of Example 1 and the charge generation layer of Example 1 were sequentially laminated to form a positive charging reverse layer photoreceptor. However, the charge generation layer was formed by spray coating. Next, the protective layer of Example-4 was provided.

[Comparative Example-3] The photosensitive member of Example-5 having no protective layer was designated as Comparative Example-3.

In the durability evaluation by CLC-200, the high voltage transformer was changed in order to reverse the polarities of primary charging, transfer charging and developing bias.

As a result of actual machine durability, in Comparative Example-3, no image appeared after several tens of sheets, whereas in Example-5, a good image was obtained after 10,000 sheets.

[Examples 6 and 7] 10 parts by weight and 0.5 part by weight of each of the monomer and the initiator of Example 3 were mixed with 90 parts by weight of methyl ethyl ketone, and then SnO ₂ fine particles (average particle size: 0.05 μm) were used. ) 3 parts by weight was added, and the mixture was dispersed at 3,300 rpm for 6 hours with a small sand mill using glass beads. The dispersion thus obtained was spray-coated on the charge transport layer of Comparative Example-1, dried at 75 ° C. for 15 minutes, irradiated with ultraviolet rays of 1500 μJ / cm ² , 120 ° C., 6
After drying for 0 minutes, a photoreceptor having a protective layer of 3.0 μm was obtained. This is Example-6. In addition, a photoreceptor having a similar protective layer provided on the charge generation layer in Example-5 is used in Example-
7

In Example 6, a normal CLC-200 was used, and in Example-7, the CLC-200 in which the polarity of the high voltage transformer used in Example-5 was changed was used. Obtained.

[Comparative Examples 4,5] The same samples were prepared and evaluated, except that the monomers used in Comparative Examples-2 were used instead of the monomers used in Examples-6 and 7. Compared to Examples 6 and 7, it was less susceptible to wear and scratches and could not be said to be a practical photoreceptor.

The details of the above results are summarized in Table 1.

Example-8 Monomer 10 of Example-1
Parts by weight, 0.5 parts by weight of the photoinitiator of Example-1, 250 parts by weight of methyl ethyl ketone and 250 parts by weight of isopropanol, and 40 parts by weight of thermoplastically modified polyethylene terephthalate (molecular weight 20,000) and hexafluoroisopropanol. A solution prepared by mixing 500 parts by weight was prepared, and the two types of solutions were further mixed and then spray-coated on the charge transport layer of Comparative Example-1. 60 ℃,
5 minutes drying, 1,500μJ / cm ² UV irradiation, 1
After drying at 20 ° C. for 60 minutes, a photoreceptor having a protective layer of 1.1 μm was obtained.

The details of the above evaluation results are summarized in Table 1.

[0065]

[Table 1]

[0066]

EFFECTS OF THE INVENTION The photoreceptor containing the monomer of the present invention in the surface layer and cured gives a surface layer of high hardness and is extremely excellent in abrasion and scratches, and therefore the dark potential is lowered over a long period of time. It has become possible to obtain a highly durable photoconductor that does not cause inconveniences such as image fogging and residual potential increase.

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

Claims (6)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the surface layer of the photoreceptor is a layer formed by polymerizing at least a compound represented by the following formula (1). An electrophotographic photosensitive member characterized by: 2. The electrophotographic photosensitive member according to claim 1, wherein the surface layer of the photosensitive member is a charge transport layer. 3. The electrophotographic photosensitive member according to claim 1, wherein the surface layer of the photosensitive member is a charge generation layer. 4. The electrophotographic photosensitive member according to claim 1, wherein the surface layer of the photosensitive member is a protective layer. 5. An electrophotographic apparatus provided with the electrophotographic photosensitive member according to claim 1. 6. A facsimile comprising the electrophotographic photosensitive member according to claim 1 and having a receiving means for receiving image information from a remote terminal.