JP2000122313A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrophotographic photoreceptor which is useful for an image forming device adopting a contact electrostatic charge system and/or a contact transfer system and is particularly excellent in wear resistance. SOLUTION: This image forming device has at least an electrostatic charge means, an image exposing means, a reversal development means, a transfer means and a cleaning means at an electrophotographic photoreceptor having an intermediate layer and a photosensitive layer on a conductive substrate 1. In such a case, the electrostatic charge means and/or transfer means of the image forming device is a contact electrostatic charge means and/or contact transfer means and the photosensitive layer of the electrophotographic photoreceptor is formed by using an aromatic compound, a cyclic etherified compound and/or their derivative solvents. The solvent residual amount in the photosensitive layer is <=1,000 ppm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus employing a contact charging system or a contact transfer system and suitable for a reversal developing system.

[0002]

2. Description of the Related Art Conventionally, a corona charger has been widely used as a charging and transferring means of an electrophotographic apparatus. However, in this method, a large amount of corona products such as ozone and NOx are generated during corona charging, causing contamination of the photoreceptor, and further, an influence on the human body and the environment has been pointed out. Therefore, in recent years, charging and transfer without using a corona charger, that is, a contact charging system and a contact transfer system have been proposed (JP-A-57-17).
No. 8267, JP-A-58-40566, JP-A-58-150975, and the like. )

[0003] In the contact charging method, the photosensitive member and the charging member come into contact with each other and rotate. Also, although the charging voltage is lower than that of corona charging, discharge occurs near the surface of the photosensitive member. The load on the photosensitive layer on the body surface is large, making the process more susceptible to wear than the corona charging method. When the photosensitive layer is worn down to a certain level or less, the charging potential is lowered to cause background contamination, and image defects (black spots) due to local discharge destruction due to contact charging. In addition, in the contact transfer unit, since a certain pressure is applied to the photoreceptor via the transfer paper, there is a problem that the photosensitive layer is strongly rubbed with the paper and easily worn as compared with the transfer unit using a corona charger. .

[0004] For these reasons, studies and studies have been conducted to improve the wear resistance of the photosensitive layer, and the results have been published. Some of them are as follows.

(1) The invention described in Japanese Patent Application Laid-Open No. 2-67562 discloses a method of fixing toner and developer to the surface of a photoreceptor by limiting the amount of residual solvent in the charge transport layer of the electrophotographic photoreceptor to 5000 ppm or less. And to prevent abnormal images (dirt) after repeated use. An object of the present invention is to provide a durable electrophotographic photoreceptor by improving the abrasion resistance of the photosensitive layer, but the abrasion resistance may not be improved depending on the type of the residual solvent.

(2) In the invention described in JP-A-3-113453, an electrophotographic photosensitive member is coated with a coating solution containing a m-phenylenediamine compound as a charge transporting material, a binder resin and tetrahydrofuran. The amount of residual tetrahydrofuran in the layer obtained by the above was 2.5 × 10 ⁻³ μ1 / m
By setting the value to g or less, an attempt is made to prevent a decrease in sensitivity when light is irradiated. The solvent for the photosensitive layer was changed to tetrahydrofuran, and the residual solvent was 2.5 × 10 ⁻³ μ1 / m.
Although the effect of stabilizing potential fluctuations (especially the potential of the exposed portion) in the actual machine is effective when the ratio is set to g or less, the effect of reducing the abrasion of the photoconductor using the contact charging / transferring means has not been clarified.

(3) In the invention described in JP-A-7-128877, the charge transport layer in a laminated electrophotographic photosensitive member is applied with a solvent having a viscosity of 0.5 cP or more at 20.degree. The amount of residual solvent in the charge transport layer is 30 to
Attempts to reduce the internal stress to provide a photoreceptor excellent in crack resistance by reducing the internal stress to 500 ppm have been made, but the description of the effect of reducing the abrasion of the photoreceptor using the contact charging / transferring means is not disclosed.

(4) The invention described in JP-A-7-152184 discloses a method in which 1,1-
It is characterized in that it contains bis (p-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene and that the solvent for coating is tetrahydrofuran. Further, the invention described in JP-A-7-219254 discloses that a certain stilbene derivative is used as a charge transporting material in a charge transporting layer of an electrophotographic photoreceptor, and a solvent for forming the coating is toluene or tetrahydrofuran. Attempts have been made to prevent cracks and abnormal images due to local charge deterioration of the photoconductor, but none of them has revealed the effect of reducing wear of the photoconductor using contact charging / transfer means.

In the invention described in JP-A-9-4388, the outermost surface layer of the electrophotographic photosensitive member has a viscosity average molecular weight of 400
It contains at least 00% of a polycarbonate resin and has a residual solvent content of 2% by weight or less of the photosensitive layer, and also refers to a method for producing the photosensitive member, an electrophotographic apparatus equipped with the photosensitive member, and a cleaning unit. ing. The invention described in Japanese Patent Application Laid-Open No. 9-160268 discloses an electrophotographic photoreceptor in which a photosensitive layer contains at least one kind of fine particles selected from organic fine particles and inorganic fine particles and an antioxidant. It is stated that prevention of defective cleaning and improvement of gas exposure resistance can be expected by setting the amount of residual solvent in the layer to 1% by weight or less. Both of them are aimed at improving the abrasion resistance, but there is no description about the abrasion in an apparatus having a contact charging means, which is insufficient.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus having at least a contact charging means, an image exposing means, a reversal phenomenon means, a cleaning means, and an electrophotographic photosensitive member. It is an object of the present invention to provide an image forming apparatus which is excellent in abrasion resistance of a layer, does not generate an abnormal image even when used for a long time, and can obtain a stable high quality image.

[0011]

According to the present invention, first, an electrophotographic photosensitive member having an intermediate layer and a photosensitive layer on a conductive substrate is provided with at least a charging unit, an image exposing unit, a reversal developing unit, and a cleaning unit. The charging means or / and the transfer means are contact charging means and / or contact transfer means, and the photosensitive layer of the electrophotographic photosensitive member is an aromatic compound and / or a derivative solvent thereof. And the residual amount of the solvent in the photosensitive layer is 1000p
pm or less.

Second, in an image forming apparatus having at least a charging unit, an image exposing unit, a reversal developing unit, and a cleaning unit on an electrophotographic photosensitive member having an intermediate layer and a photosensitive layer on a conductive substrate, And / or the transfer means is a contact charging means or / and a contact transfer means, and the photosensitive layer of the electrophotographic photoreceptor is made of a cyclic ether compound and / or a derivative thereof, and the solvent in the photosensitive layer is An image forming apparatus having a residual amount of 1000 ppm or less is provided.

Third, drying of the outermost surface layer of the photosensitive layer is 1
The first or second image forming apparatus is provided at a temperature of 20 ° C. or more and 150 ° C. or less.

Fourth, drying of the outermost surface layer of the photosensitive layer requires 1
After pre-drying at 00 ° C or less, 120 ° C or more and 150 ° C
The third image forming apparatus is provided, which is performed at the following temperature.

Fifthly, the image forming apparatus according to any one of the first to fourth aspects is provided, wherein the viscosity of the coating solution for the photosensitive layer at 20 ° C. is 600 cP or less.

Sixth, the coating liquid for the photosensitive layer is prepared at a solid concentration such that the viscosity at 20 ° C. becomes 200 cP or less, and then adjusted to a desired solid concentration. The fifth image forming apparatus described above is provided.

Seventh, the image forming apparatus according to any one of the first to third to sixth aspects, wherein the aromatic compound and / or derivative solvent is toluene or benzene.

Eighth, the image forming apparatus according to any one of the second to sixth aspects, wherein the cyclic ether compound and / or its derivative solvent is tetrahydrofuran, dioxane, or tetrahydropyran. .

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. FIG. 1 schematically shows an example of the image forming apparatus of the present invention. As shown in this figure, the photosensitive member 12 is charged to a predetermined positive or negative voltage by the charging member 1 which contacts the outer peripheral surface of the drum-shaped electrophotographic photosensitive member 12 rotating in the direction of arrow A. A positive or negative DC voltage is applied to the charging member 1. DC voltage applied to the charging member 1 is -2000V
+ 2000V is preferred. In addition to the DC voltage, an AC voltage may be superimposed on the charging member 1 to apply a pulsating voltage. The AC voltage superimposed on the DC voltage is preferably one having a peak-to-peak voltage of 4000 V or less. However, when the AC voltage is superimposed, the charging member and the electrophotographic photosensitive member may vibrate to generate an abnormal sound. A desired voltage may be applied to the charging member 1 instantaneously, or the applied voltage may be gradually increased to protect the photoconductor.

The charging member 1 may rotate in the same or opposite direction as the photosensitive member 12, or may slide on the outer peripheral surface of the photosensitive member 12 without rotating. Further, the charging member 1 may have a function of cleaning residual toner on the photoconductor 12. In this case, there is no need to provide the cleaning means 10.

The charged photoconductor 12 is then subjected to light image exposure 6 (slit exposure, laser beam scanning exposure, etc.) by an image exposure means (not shown). At the time of this exposure scanning, the exposure is interrupted for the non-image portion of the current surface,
A developing bias slightly lower than the surface potential is applied to the image portion which has become a low potential due to the exposure, thereby inverting the potential of the image portion, thereby forming an electrostatic image corresponding to the original image including the non-image portion described above. Latent images are sequentially formed.

The electrostatic latent image is then developed with toner by reversal developing means 7, and the toner image is transferred between the photosensitive member 12 and the transfer member 8 by a transfer unit 8 from a paper feed unit (not shown). Are sequentially transferred to the surface of the recording material 9 fed in synchronization with the rotation of the recording material 9. Recording material 9 after image transfer
The photoreceptor is separated from the photoreceptor surface, introduced into an image fixing means (not shown), subjected to image fixing, and is heblinted out of the apparatus as a copy. The surface of the photoreceptor 12 after the image is transferred is subjected to removal of the untransferred toner by the cleaning unit 10 so as to have a normal surface.

As the electrophotographic apparatus, a plurality of components such as the above-described photosensitive member and developing means are integrally connected as an apparatus unit, and this unit is configured to be detachable from the apparatus body. May be. For example, as shown in FIG. 2, at least the photosensitive member 12, the charging member 1, and the reversal developing means 7 are housed in a container 20 to form one electrophotographic apparatus unit, and this apparatus unit is used by a guide means such as a rail of the apparatus body. It may be configured to be detachable. The cleaning means 10 may or may not be provided in the container 20. As shown in FIG. 3, at least the photosensitive member 12 and the charging member 1 are contained in a first container 21 to form a first electrophotographic unit, and at least the reversal developing means 7 is provided in a second container 2.
2 to form a second electrophotographic unit, and the first device unit and the second device unit may be configured to be detachable. The cleaning means 10 may or may not be provided in the container 21.

In FIGS. 2 and 3, a transfer member 23 of a contact transfer system is used as a transfer means. The transfer member 23 having the same configuration as the charging member 1 can be used. 400 V is applied to the transfer member 23 used as a transfer unit.
It is desirable to apply a DC voltage of ~ 2000V. Reference numeral 24 denotes a fixing unit.

The charging member 1 may have any shape such as a roller shape, a brush shape, a blade shape, and a flat plate shape. The roller-shaped charging member 1 has an elastic layer, a conductive layer, and a resistance layer around a rod-shaped conductive core material.

As the conductive core material, a metal such as iron, copper, or stainless steel, or a conductive resin such as a carbon-dispersed resin or a metal-particle-dispersed resin can be used. Can be used.

The elastic layer is a layer rich in elasticity and high in hardness, and is 1.5 mm or more, more preferably 2 mm or more, especially 3 mm or more.
(Thickness) of 〜13 mm is preferred. As a material used for the elastic layer, for example, chloroprene rubber, isoprene rubber,
EPDM rubber, polyurethane rubber, epoxy rubber, butyl rubber and the like are preferred.

The conductive layer is a layer having a high electric conductivity and has a volume resistivity of 10 ⁷ Ω · cm or less, more preferably 10 ⁶ Ω · cm or less, especially 10 ⁻² Ω · cm to 10 ⁶ Ω · cm. Those in the range are preferred. The thickness of the conductive layer is desirably a thin layer to transmit the flexibility of the lower elastic layer to the upper resistive layer,
3 mm or less, further 2 mm or less, especially 20 μm to 1 m
The range of m is preferred. As the material used for the conductive layer,
A metal deposition film, a conductive particle-dispersed resin, a conductive resin, or the like can be used. Examples of the metal deposition film include a film obtained by vapor deposition of a metal such as aluminum, indium, nickel, copper, and iron.

As the conductive particle-dispersed resin, for example, conductive particles such as carbon, aluminum, nickel and titanium oxide are dispersed in a resin such as urethane, polyester, vinyl acetate-vinyl chloride copolymer and polymethyl methacrylate. Things. As the conductive resin, for example, 4
Secondary ammonium salt-containing polymethyl methacrylate, polyvinylaniline, polyvinylpyrrole, polydiacetylene, polyethyleneimine, and the like.

The resistance layer is formed to have a higher resistance value than the conductive layer, and has a volume resistivity of 10 ⁶ to 10 ¹² Ω ·
cm, more preferably 10 ⁷ to 10 ¹¹ Ω · cm, and a semiconductive resin, a conductive particle dispersed insulating resin, or the like can be used. As the semiconductive resin, for example, ethyl cellulose, nitrocellulose, methoxymethylated nylon, ethoxymethylated nylon, copolymerized nylon,
Resins such as polyvinylpyrrolidone and casein, and mixtures of these resins, and the like. As the conductive particle-dispersed insulating resin, for example, carbon, aluminum, indium oxide, conductive particles such as titanium oxide urethane,
Examples thereof include those in which the resistance is adjusted by dispersing a small amount in an insulating resin such as polyester, vinyl acetate-vinyl chloride copolymer, or polymethacrylic acid. The thickness of the resistance layer is from 1 μm to 500 μm, particularly from 50 μm to 200 μm from the viewpoint of chargeability.
m is preferred.

The flat charging member is formed by providing an elastic layer and a resistance layer on a metal plate. The brush-shaped charging member is formed by providing conductive fibers radially around a conductive core material via an adhesive layer, or by providing conductive fibers on one surface of a metal flat plate via an adhesive layer. The conductive fiber is a fiber having a high electric conductivity, and has a volume resistivity of 10 ⁸ Ω · cm or less, more preferably 10 ⁶ Ω · cm or less, particularly 10 ⁻² Ω · cm to 10 ⁶ Ω · c.
A range of m is preferred. The thickness of one conductive fiber is desirably small in order to maintain flexibility.
-100 μm, more preferably 5-50 μm, especially 8-30 μm
The range of m is preferred. Conductive fiber length is 2-10m
m, more preferably 3 to 8 mm. As the material for forming the conductive fiber, for example, the above-described conductive particle-dispersed resin, conductive resin, or the like can be used. Further, carbon fibers can also be used for the conductive fibers.

Next, the photoconductor 12 used in the present invention will be described. FIG. 4 is a cross-sectional view showing a configuration example of the photoconductor 12 of the present invention, and has a configuration in which at least an intermediate layer 33 and a photosensitive layer 35 are laminated on a conductive support 31.
FIG. 5 is a cross-sectional view showing another example of the configuration of the photoconductor 12 of the present invention, which has a configuration in which an intermediate layer 33, a charge generation layer 37, and a charge transport layer 39 are stacked on a conductive support 11. .

The solvent used in the coating solution for forming the photosensitive layer 35 and the charge transport layer 39 is an aromatic compound and / or a derivative thereof, and further a cyclic ether compound and / or a derivative thereof. .

Examples of the aromatic compound and / or its derivative include benzene, toluene, xylene and its isomer, ethylbenzene, diethylbenzene, isopropylbenzene, acylbenzene, p-cymene, naphthalene, tetralin, biphenyl and the like. Examples of the cyclic ether compound and / or its derivative include 1,4-dioxane and its derivative, trioxane, tetrahydrofuran and its derivative, furan and its derivative, furfural, 2-methylfuran, and tetrahydropyran.

These solvents may be used alone or as a mixture of two or more. Among them, benzene, toluene, tetrahydrofuran, 1,4-dioxane, and tetrahydropyran are preferably used. These solvents may also contain other solvents such as monochlorobenzene, dichloromethane, cyclohexanone, methyl ethyl ketone,
You may mix and use with acetone etc.

The photosensitive layer forming solution prepared by using these solvents and the photosensitive layer 3 formed by the charge transporting layer forming solution.
5. The charge transport layer 39 has a residual solvent content of 1000 pp.
m or less. If the content is 1000 ppm or more, the abrasion resistance of the photosensitive layer 15 and the charge transport layer 19 decreases, which is not preferable.

The drying of the photosensitive layer 35 or the charge transporting layer 39 is 1
It is preferable to carry out at a temperature of from 20 ° C to 150 ° C. 1
If the temperature is lower than 20 ° C., the abrasion resistance of the photosensitive layer 15 and the charge transporting layer 19 is inferior. Furthermore, when the drying temperature is set to 120 ° C. or higher,
When drying from room temperature to 120 ° C or more,
Bubbles are generated and discharge breakdown easily occurs in charging by the contact charger, which causes image defects such as black spots. Therefore, it is preferable to perform preliminary drying at a temperature of 100 ° C. or lower and then dry at 120 ° C. or higher.

The viscosity of the coating solution for the photosensitive layer 15 and the charge transport layer 19 at 20 ° C. is preferably 600 cP or less. If it is more than this, the photosensitive layer 15 and the charge transport layer 1
9 has reduced wear resistance. Further, from the viewpoint of abrasion resistance, the liquid viscosity is preferably as low as possible in order to sufficiently entangle the resin molecules after drying, but is limited in order to obtain a desired film thickness. Although a method such as recoating is also conceivable, it is not preferable because the cost increases due to the addition of manufacturing equipment. As a result of study, when the resin is dissolved in the solution, if it is dissolved in a state of sufficiently low viscosity of 200 cP or less once at 20 ° C., then the solvent is volatilized to increase the viscosity even if the viscosity is increased. The properties were found to remain excellent.

The photosensitive layer 35 and the charge transport layer 39 are formed by dissolving or dispersing the photoconductive substance and the binder resin in the above-mentioned solvent, or dissolving or dispersing the charge transport substance and the binder resin in the above-mentioned solvent, This can be formed on the intermediate layer 33 or on the charge generation layer 37 by applying and drying. Also,
If necessary, a plasticizer, a leveling agent, an antioxidant and the like can be added.

The charge transport material includes a hole transport material and an electron transport material. Examples of the electron transporting substance include chloranil, bromanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone,
2,4,8-trinitrothioxanthone, 2,6,8-
Trinitro-4H-indeno [1,2-b] thiophene-
Electron accepting substances such as 4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, and benzoquinone derivatives.

Examples of the hole transport material include poly-N-vinylcarbazole and its derivatives, poly-γ-carbazolylethyl glutate and its derivatives, pyrene-formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, and polysilane. , Oxal derivative, oxadial derivative, imidal derivative,
Monoalamine derivatives, dialalamine derivatives, trialamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazine derivatives, indene Well-known materials such as derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives, enamine derivatives, and other polymerized hole transporting substances are exemplified.

Examples of the binder resin used for the charge transport layer 39 include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, and the like.
Vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate, phenoxy resin,
Polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin, JP-A-158250 / JP-A-6-5
Thermoplastic or thermosetting resins such as various polycarbonate copolymers described in JP-A-1544.

The amount of the charge transporting substance is 20 to 300 parts by weight, preferably 40 to 150 parts by weight, per 100 parts by weight of the binder resin.
Parts by weight are appropriate. The thickness of the charge transport layer 39 is 5
It is preferable to set it to about 50 μm.

In the present invention, a leveling agent and an antioxidant may be added to the photosensitive layer 35 and the charge transport layer 39. As the leveling agent, silicone oils such as dimethyl silicone oil and methyl phenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in a side chain can be used. 0 to 1 part by weight is suitable. As the antioxidant, an antioxidant such as a hindered phenol compound, a sulfur compound, a phosphorus compound, a hindered amine compound, a pyridine derivative, a piperidine derivative, and a morpholine derivative can be used. About 0 to 5 parts by weight per part is appropriate.

As a method for applying the coating solution, a dip coating method, a spray coat, a bead coat, a nozzle coat, a spinner coat, a ring coat, a Meyer bar coat, a roller coat, a curtain coat and the like can be used.

The intermediate layer 13 of the photoreceptor 12 preferably contains titanium oxide. Titanium oxide has little absorption in visible light and near-infrared light and is white, which is desirable for increasing the sensitivity of the photoreceptor. Further, since the refractive index is relatively large, moire generated when writing an image with coherent light such as laser light can be effectively prevented. Also, the intermediate layer 33
The binder resin is contained together with titanium oxide. Examples of the resin include thermoplastic resins such as polyvinyl alcohol, casein, sodium polyacrylate, copolymerized nylon, and methoxymethylated nylon, polyurethane, melamine, epoxy, and alkyd. Phenol, butyral, and unsaturated polyester resins.

Further, the ratio P / R of the titanium oxide (P) to the binder resin (R) contained in the intermediate layer 33 of the present invention is in the range of 0.9 / 1 to 2/1 by volume. Is preferred.
If the P / R ratio of the intermediate layer is less than 0.9 / 1, the characteristics of the intermediate layer depend on the characteristics of the binder resin, and the characteristics of the photoreceptor greatly change particularly when the temperature and humidity change and repeated use. . On the other hand, if the P / R ratio exceeds 2/1, voids increase in the intermediate layer, the adhesiveness to the charge generation layer decreases, and if the P / R ratio exceeds 3/1, air is collected so that air accumulates. Causes bubbles during coating and drying of the photosensitive layer,
Coating defects will result.

In addition to titanium oxide, a fine powder pigment of a metal oxide such as aluminum oxide, silica, zirconium oxide, tin oxide or indium oxide is added to the intermediate layer 33 in order to prevent moiré and reduce residual potential. Is also good. Further, as the intermediate layer 33 of the present invention, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, a titanyl chelate compound, a zirconium chelate compound, a titanyl alkoxide compound, and an organic titanyl compound can also be used. These intermediate layers 33 can be formed by using an appropriate solvent, dispersion, and coating method as in the above-described photosensitive layer.
In addition, the intermediate layer 33 of the present invention is provided with Al ₂ O ₃ by anodic oxidation, an organic substance such as polyparaxylylene, or an organic material such as SiO ₂ , SnO ₂ , TiO ₂ , ITO, and CeO ₂ . An inorganic substance provided by a vacuum thin film forming method can also be used favorably.

The thickness of the intermediate layer 33 is suitably from 0 to 10 μm.

As the charge generating substance used in the photosensitive layer 35 and the charge generating layer 37, in addition to metal-free phthalocyanine and titanyl phthalocyanine pigments, azo pigments such as monoazo pigments, bisazo pigments, asymmetric disazo pigments, trisazo pigments, and tetraazo pigments , Pyrrolopyrrole pigments, anthraquinone pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, squarium pigments, pyrene pigments, diphenylmethane pigments, azine pigments, quinoline pigments, and other known materials can be used. The effect becomes remarkable by using a phthalocyanine pigment among them. These charge generating substances can be used in combination.

As a binder resin used for the charge generation layer 37, a butyral resin is used as a main component (50 wt% or more).
Epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl formal, polyvinyl ketone, polystyrene, poly-vinyl carbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate , Polyamide, polyvinyl pyridine, cellulosic resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, and the like. The amount of the binder resin is 10 to 500 parts by weight, preferably 25 to 30 parts by weight, per 100 parts by weight of the charge generating substance.
0 parts by weight is suitable.

The solvents used here include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane,
Examples include toluene, xylene, and ligroin. The charge generation layer 37 is obtained by mixing these components in a suitable solvent using a ball mill.
It is formed by dispersing using an attritor, a sand mill, an ultrasonic wave or the like, applying this on the intermediate layer 33, and drying.

The thickness of the charge generation layer 37 is 0.01 to 5 μm.
m, preferably 0.1 to 2 μm.

The conductive support 31 has a volume resistance of 10
Those exhibiting a conductivity of ¹⁰ Ωcm or less, for example, aluminum, nickel, chromium, nichrome, copper, gold, silver, metals such as platinum, tin oxide, metal oxides such as indium oxide, by evaporation or sputtering, Film or cylindrical plastic or paper coated or plates made of aluminum, aluminum alloy, nickel, stainless steel, etc. and extruded, drawn out, etc., then tubed, cut, super finished, polished etc. Can be used. Further, an endless nickel belt and an endless stainless belt disclosed in JP-A-52-36016 can also be used as the conductive support 11.

In addition to the above, a support obtained by dispersing a conductive powder in a suitable binder resin on the above support and applying the same can also be used as the conductive support 11 of the present invention. Examples of the conductive powder include carbon black, acetylene black, metal powders such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, and metal oxides such as conductive titanium oxide, conductive tin oxide, and ITO. And powder. The binder resins used simultaneously include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, and vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate,
Cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin,
Examples include thermoplastic resins such as silicone resins, epoxy resins, melamine resins, urethane resins, phenol resins, and alkyd resins, thermosetting resins, and photocurable resins. Such a conductive layer can be provided by dispersing the conductive powder and the binder resin in an appropriate solvent, for example, tetrahydrofuran, dichloromethane, 2-butanone, toluene, or the like, and applying the dispersion.

Further, a conductive material is formed by a heat-shrinkable tube in which a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon or the like contains the conductive powder on a suitable cylindrical substrate. Those provided with a layer can also be favorably used as the conductive support 31 of the present invention.

[0057]

Next, the present invention will be described in detail with reference to examples.

Example 1 70 parts by weight of titanium oxide (CREL: manufactured by Ishihara Sangyo), 15 parts by weight of alkyd resin (Beccolite M6401-50-S (solid content: 50%): manufactured by Dainippon Ink and Chemicals), melamine resin ( Super Beckamine L-121-60 (solid content: 60%): 10 parts by weight, manufactured by Dainippon Ink and Chemicals,
A mixture consisting of 100 parts by weight of methyl ethyl ketone was
The mixture was dispersed for 72 hours with a mil mill to prepare a coating liquid for an intermediate layer, which was applied on an aluminum drum having a diameter of 80 mm and a length of 359 mm, and dried at 130 ° C. for 20 minutes to form an intermediate layer having a thickness of 3 μm. Produced.

Next, the trisazo pigment 1 of the following structural formula (1)
9 parts by weight and 1 part by weight of the disazo pigment of the following structural formula (2) were added to a resin solution prepared by dissolving 4 parts by weight of polyvinyl butyral (BM-2: manufactured by Sekisui Chemical Co., Ltd.) in 150 parts by weight of cyclohexanone. For 72 hours. After completion of the dispersion, 210 parts by weight of cyclohexanone was added, and the mixture was further dispersed for 3 hours to prepare a coating liquid for a charge generation layer. This is applied on the intermediate layer, and
After drying for 2 minutes, a charge generation layer having a thickness of 0.2 μm was formed.

Embedded image

Embedded image

Next, 8 parts by weight of a charge transporting substance represented by the following structural formula (3), 10 parts by weight of polycarbonate (Z type: viscosity average molecular weight of 40,000), and silicone oil (KF-5)
0: manufactured by Shin-Etsu Chemical Co., Ltd.) 0.002 parts by weight of toluene 1
The resultant was dissolved in 00 parts by weight to prepare a charge transport layer coating solution.
The viscosity at 20 ° C. of this coating liquid was 380 cP. This is applied on the charge generation layer,
After drying for 30 minutes, a charge transport layer having a thickness of 30 μm was formed, and an electrophotographic photosensitive member provided in the electrophotographic image forming apparatus of the present invention was produced.

Embedded image

The charge transporting layer at the end of the electrophotographic photosensitive member thus formed was peeled off, and pyrolysis gas chromatography was performed.
The amount of residual solvent in the photosensitive layer (charge transport layer) was measured using a GC15A (manufactured by Shimadzu Corporation) and a Curie Point Pipe Roller Iser (JHP-3S: manufactured by Nippon Kagaku Kogyo).

Example 2 Example 1 was the same as Example 1 except that the charge transport layer was dried at 130 ° C. for 10 minutes. When the amount of the residual solvent in the photosensitive layer (charge transport layer) was measured, it was 950 ppm.
Met.

Example 3 Example 1 The same as Example 1 except that the charge transport layer was dried at 120 ° C. for 60 minutes. It was 800 ppm when the amount of residual solvent in the photosensitive layer (charge transport layer) was measured.

Example 4 Example 1 was the same as Example 1 except that the charge transport layer was dried at 150 ° C. for 20 minutes. When the amount of the residual solvent in the photosensitive layer (charge transport layer) was measured, it was 280 ppm.
Met.

Example 5 The procedure of Example 1 was repeated except that the charge transport layer was dried at 170 ° C. for 10 minutes. It was 50 ppm when the amount of residual solvent in the photosensitive layer (charge transport layer) was measured.

Example 6 The same conditions as in Example 1 were employed except that the charge transport layer in Example 1 was dried at 100 ° C. for 6 minutes, and then dried at 130 ° C. for 20 minutes. When the amount of the residual solvent in the photosensitive layer (charge transport layer) was measured, it was 570 ppm.

Example 7 The procedure of Example 6 was repeated except that the amount of the toluene for the charge transport layer coating solution was changed to 90 parts by weight. The viscosity at 20 ° C. of this coating solution was 600 cP.

Example 8 The procedure of Example 6 was repeated, except that the charge transport layer coating liquid of Example 6 was changed to 85 parts by weight of toluene. 20 of this coating liquid
The viscosity at 800C was 800 cP.

Example 9 The charge transport layer coating liquid of Example 6 was changed to 110 parts by weight of toluene. The viscosity at 20 ° C. of this coating liquid is 200
cP. Next, the coating liquid was kept at 40 ° C. with a hot stirrer, and toluene was gradually evaporated so that the solid content concentration was the same as in Example 6. Example 6 was the same as Example 6 except that this coating solution was used as the coating solution for the charge transport layer.

Example 10 Example 10 was the same as Example 6 except that benzene was used instead of toluene. When the amount of the residual solvent in the photosensitive layer (charge transport layer) was measured, it was 920 ppm.

Comparative Example 1 The drying conditions for the charge transport layer coating solution in Example 1 were
Example 1 was the same as Example 1 except that the temperature was changed to 10 ° C. for 30 minutes. It was 7600 ppm when the residual solvent amount in this photosensitive layer (charge transport layer) was measured.

Comparative Example 2 The drying conditions of the coating solution for the charge transport layer in Example 1 were
Example 1 was the same as Example 1 except that the temperature was changed to 20 ° C. for 30 minutes. The amount of residual solvent in this photosensitive layer (charge transport layer) was measured and found to be 1300 ppm.

Example 11 Example 11 was the same as Example 6 except that m-xylene was used instead of toluene. When the amount of the residual solvent in the photosensitive layer (charge transport layer) was measured, it was 9800 ppm.
Met.

Example 12 The procedure of Example 1 was repeated except that 80 parts by weight of tetrahydrofuran was used instead of 100 parts by weight of toluene in the coating solution for the charge transport layer of Example 1. The viscosity at 20 ° C. of this coating solution for a charge transport layer was 350 cP. When the amount of the residual solvent in the photosensitive layer (charge transport layer) was measured,
It was 00 ppm.

Example 13 Example 12 was the same as Example 12 except that the charge transporting layer was dried at 130 ° C. for 10 minutes. When the amount of residual solvent in the photosensitive layer (charge transport layer) was measured,
It was 0 ppm.

Example 14 Example 12 was the same as Example 12 except that the drying conditions of the charge transport layer were drying at 120 ° C. for 60 minutes. When the amount of residual solvent in the photosensitive layer (charge transport layer) was measured, it was found to be 85
It was 0 ppm.

Example 15 Example 15 was the same as Example 1 except that the charge transport layer was dried at 150 ° C. for 20 minutes. When the amount of the residual solvent in the photosensitive layer (charge transport layer) was measured, it was 200 p.
pm.

Example 16 Example 12 was the same as Example 12 except that the charge transport layer was dried at 170 ° C. for 10 minutes. When the amount of the residual solvent in the photosensitive layer (charge transport layer) was measured,
ppm.

Example 17 Example 12 was the same as Example 12 except that the charge transport layer was dried at 100 ° C. for 6 minutes and then at 130 ° C. for 20 minutes. When the amount of the residual solvent in the photosensitive layer (charge transport layer) was measured, it was 570 ppm.

Example 18 The procedure of Example 17 was repeated except that the amount of tetrahydrofuran in the coating liquid for the charge transport layer of Example 17 was changed to 70 parts by weight. The viscosity at 20 ° C. of this coating solution was 600 cP.

Example 19 The procedure was the same as that of Example 17 except that the coating liquid for the charge transport layer of Example 17 was changed to 65 parts by weight of tetrahydrofuran. The viscosity at 20 ° C. of this coating solution was 800 cP.

Example 20 The coating liquid for a charge transport layer of Example 17 was adjusted to 90 parts by weight of tetrahydrofuran. The viscosity at 20 ° C. of this coating solution was 200 cP. Next, this coating liquid was maintained at 40 ° C. with a hot stirrer, and tetrahydrofuran was volatilized gradually so that the solid content concentration was the same as in Example 12. Example 17 was the same as Example 17 except that this coating solution was used as the coating solution for the charge transport layer.

Example 21 In place of tetrahydrofuran in Example 17,
Same as Example 17 except that 1,4-dioxane was used. When the amount of the residual solvent in the photosensitive layer (charge transport layer) was measured, it was 920 ppm.

Example 22 Example 17 was the same as Example 17 except that tetrahydropyran was used instead of tetrahydrofuran. It was 650 ppm when the residual solvent amount in the photosensitive layer (charge transport layer) was measured.

Comparative Example 3 The drying conditions of the charge transport layer coating solution in Example 12 were changed to 11
Example 12 was the same as Example 12 except that the temperature was changed to 0 ° C. for 30 minutes. It was 7600 ppm when the residual solvent amount in this photosensitive layer (charge transport layer) was measured.

Comparative Example 4 The drying conditions of the charge transport layer coating liquid in Example 12 were as follows:
Example 12 was the same as Example 12 except that the temperature was 120 ° C. for 30 minutes. The amount of residual solvent in this photosensitive layer (charge transport layer) was measured and found to be 1100 ppm.

The electrophotographic photosensitive drums of Examples 1 to 22 and Comparative Examples 1 to 4 were manufactured by Ricoh Co., Ltd.
Using F200, a durability test was performed on 20,000 sheets continuously using chart paper having a black solid portion of 5%, the film thickness before and after the test was measured, and the abrasion film thickness was calculated. In addition, other abnormal images were observed. The results are shown in Table 1.

[0088]

[Table 1]

[0089]

According to the first or second aspect of the present invention,
In an image forming apparatus having at least a charging unit, an image exposing unit, a reversal developing unit, a transferring unit, and a cleaning unit on an electrophotographic photosensitive member having an intermediate layer and a photosensitive layer on a conductive substrate, the charging unit or / and the The transfer means is a contact charging means and / or a contact transfer means, and the photosensitive layer of the electrophotographic photosensitive member is formed using an aromatic compound, a cyclic ether compound and / or a derivative-based solvent thereof, and the residual amount of the solvent Is 1000 ppm or less,
It is possible to provide a durable image forming apparatus with less wear of the photosensitive layer in long-term use.

(2) According to the third or fourth aspect of the present invention, the outermost surface layer of the photosensitive layer is preliminarily dried at 120 ° C. to 150 ° C., preferably 100 ° C. or less, and then dried at 120 ° C. to 150 ° C. By drying, the occurrence of an abnormal image such as a black spot image due to discharge breakdown is eliminated, and a higher quality image can be provided.

(3) According to the invention of claim 5 or 6, the photosensitive layer coating liquid is prepared at a solid content concentration such that the viscosity at 20 ° C. becomes 600 cP or less, preferably the viscosity at 20 ° C. becomes 200 cP or less. After that, it can be more effectively achieved by adjusting the solid content to a desired concentration.

(4) According to the invention of claim 7 or 8, the aromatic compound, the cyclic ether compound and / or the derivative solvent thereof used for preparing the coating solution for the photosensitive layer are preferably toluene, benzene, tetrahydrofuran, dioxane. , Tetrahydropyran achieves each of the above items effectively.

[Brief description of the drawings]

FIG. 1 is a front view showing an example of the electrophotographic apparatus of the present invention.

FIG. 2 is a front view showing another example of the electrophotographic apparatus of the present invention.

FIG. 3 is a front view showing another example of the electrophotographic apparatus of the present invention.

FIG. 4 is a diagram illustrating a layer configuration of the electrophotographic photosensitive member of the present invention.

FIG. 5 is a diagram showing a layer configuration of another electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Charging member 6 Exposure means 7 Reversal developing means 8 Transfer member (Corona method) 9 Recording material 10 Cleaning means 11 Static elimination means 12 Photoconductor 20 Container 21 Container 22 Container 23 Transfer member (Contact transfer method) 24 Fixing means 31 Conductive support Body 33 Intermediate layer 35 Photosensitive layer 37 Charge generation layer 39 Charge transport layer

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Yasuo Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (Reference) 2H003 BB11 CC04 DD03 2H032 AA05 2H068 AA21 BA01 BA11 EA13 EA14 EA15 EA19 EA32 EA36 EA41 FC01

Claims (8)

[Claims] 1. An image forming apparatus comprising: an electrophotographic photosensitive member having an intermediate layer and a photosensitive layer on a conductive substrate; and at least a charging unit, an image exposing unit, a reversal developing unit, a transferring unit, and a cleaning unit. And / or the transfer unit is a contact charging unit or / and a contact transfer unit, and the photosensitive layer of the electrophotographic photoreceptor is made of an aromatic compound and / or a derivative thereof, and a solvent in the photosensitive layer is used. An image forming apparatus having a residual amount of 1000 ppm or less. 2. An image forming apparatus comprising: an electrophotographic photosensitive member having an intermediate layer and a photosensitive layer on a conductive substrate; and at least a charging unit, an image exposing unit, a reversal developing unit, a transferring unit, and a cleaning unit. And / or the transfer means is a contact charging means or / and a contact transfer means, and the photosensitive layer of the electrophotographic photoreceptor is made of a cyclic ether compound and / or a derivative thereof, and the solvent in the photosensitive layer An image forming apparatus having a residual amount of 1000 ppm or less. 3. The drying of the outermost surface layer of the photosensitive layer is performed at 120 ° C.
The image forming apparatus according to claim 1, wherein the temperature is set to a temperature of 150 ° C. or lower. 4. The drying of the outermost surface layer of the photosensitive layer is performed at 100 ° C.
4. The image forming apparatus according to claim 3, wherein the preliminarily drying is performed at a temperature of 120 to 150 [deg.] C. 5. The coating liquid for the photosensitive layer has a viscosity at 20 ° C. of 600 cP or less.
5. The image forming apparatus according to any one of claims 1 to 4, 6. The coating solution for the photosensitive layer is prepared at a solid concentration such that the viscosity at 20 ° C. is 200 cP or less, and then adjusted to a desired solid concentration. Item 6. The image forming apparatus according to Item 5. 7. The image forming apparatus according to claim 1, wherein the aromatic compound and / or its derivative solvent is toluene or benzene. 8. The image forming apparatus according to claim 2, wherein the cyclic ether compound and / or a derivative solvent thereof is tetrahydrofuran, dioxane, or tetrahydropyran.