JPH0683096A - Electrophotographic sensitive body and electrophotographic device - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body without causing nonuniform or deficient transfer in multiple transfer. CONSTITUTION:The electrophotographic sensitive body to be used in an electrophotographic device is charged, exposed, developed, transferred and cleaned to form a picture on a transfer material. In this case, transfer is conducted by a member for supporting the transfer material synchronized with the single sensitive body, transfer is applied to one transfer material more than twice, and the second and succeeding pictures onward are successively and synchronously overlapped on the first picture on the transfer material. The sensitive body contains a fluorine-substituted resin powder in its surface layer. Consequently, the driving load is reduced, and a high-quality picture without any nonuniform transfer, deficient transfer, nonuniform driving pitch, color slurring, etc., is provided by this electrophotographic device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member and an electrophotographic apparatus, and more particularly to an electrophotographic photosensitive member which is used in a multiple transfer process and realizes a high quality image free from transfer defects, color misregistration, pitch unevenness and the like. The present invention relates to an electrophotographic device.

[0002]

2. Description of the Related Art Conventionally, inorganic materials such as zinc oxide, selenium and cadmium sulfide have been known as photoconductive materials used in electrophotographic photoreceptors. Organic polyvinylcarbazole, phthalocyanine, azo pigments and the like have come to be widely used although their advantages such as high productivity and pollution-free have been noted, and they are inferior in photoconductive characteristics and durability. . Recently, new materials are being devised in which these drawbacks have been improved, and in particular, their photoconductive properties are surpassing those of inorganic materials.

These electrophotographic photoconductors are repeatedly subjected to various actions such as charging, exposure, development, transfer, cleaning and charge removal in the electrophotographic process of copying machines, laser beam printers and the like, so that they are subjected to various chemical and physical processes. Durability is required. In particular, the surface properties such as the surface energy of the photoconductor are involved in the developer transferability on the photoconductor, stains on the photoconductor, etc., and are important factors for obtaining a high quality image.
On the other hand, the above-mentioned organic photoconductive material generally does not have film-forming properties, so that it is generally formed together with a binder resin. Therefore, it is no exaggeration to say that the surface properties such as surface energy are almost limited by the selection of the binder resin. However, the binder resins that satisfy the photoconductive properties are quite limited, and in reality, the desired surface properties have not been obtained. The binder resin used in the photoreceptor using the organic photoconductor, polyester, polyurethane, polyarylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, polyamide imide, polysulfone, polyallyl ether, polyacetal, Nylon, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, butyral resin and the like can be mentioned, but none of them gives a sufficiently low energy surface.

[0004]

In recent years, an electrophotographic process capable of faithfully reproducing a color image has been required, and several systems have been proposed. Among them, as shown in Figure 1,
The photoconductor drum and the transfer drum that holds the transfer material such as transfer paper are synchronized in a one-to-one manner, and three types of three primary colors or four-color images in which black is added to them are transferred on the transfer material at a time. An apparatus that employs a 1-drum multiple transfer system that reproduces color images in a superimposed manner is common.

One of the problems in such a process is the transfer efficiency of the second and subsequent colors at the time of multiple transfer. Since the transfer of the second color and thereafter is carried out via the developer already transferred onto the transfer material such as transfer paper, it can give only a more indirect transfer action than usual. As a result, the pre-transfer developer on the photoconductor is not sufficiently transferred to the transfer material side, and only a low quality image may be obtained due to transfer failure. In particular, when the above-mentioned conventional organic photoconductor is used, image defects such as uneven transfer of solid image portions and voids in transfer of character portions occur.

Another problem is the problem of driving load on the photoconductor. In particular, the cleaning step of removing the developer remaining on the photoconductor after transfer has a great influence on the driving load. As a cleaning method, it is desirable to employ blade cleaning in order to realize a simpler device configuration in association with space saving of the device. The blade cleaning has a simple configuration in which an elastic member such as a plate-shaped polyurethane is merely abutted on the photoconductor in the generatrix direction. However, when the above-mentioned conventional organic photoconductor is used, a large frictional force is generated between the photoconductor and the blade, which imposes a great load on the drive of the photoconductor. As a result, irregularities such as driving unevenness occur in the driving of the photoconductor, and color misregistration that causes a deviation in the images of the second and subsequent colors at the time of multiple transfer, and image defects such as driving pitch unevenness that causes the driving unevenness to become image density unevenness. cause. In particular, in a device that forms a dot-shaped minute latent image by using a laser, an LED, a liquid crystal shutter, etc. as a light source for forming a latent image, unless the dots are superimposed with high precision during multiple transfer, micron order Color shift easily occurs, which causes color tone shift and deterioration of image sharpness.

An object of the present invention is to improve the surface properties of a photoreceptor without deteriorating the electrophotographic characteristics, and in particular, the surface energy is low and the transfer characteristics at the time of multiple transfer and the driving load of the photoreceptor are improved. To obtain the body and electrophotographic device.

[0008]

The electrophotographic photosensitive member of the present invention is a photosensitive member used in an electrophotographic apparatus including a multiple transfer step, and has a surface energy lower than that of a conventional photosensitive member. Solves the problem.

That is, the present invention provides an electrophotographic photosensitive member used in an electrophotographic apparatus which forms an image on a transfer material through at least the steps of charging, exposing, developing, transferring and cleaning, and the transferring step is a single photosensitive member. A transfer material supporting member that supports the transfer material in synchronism with the transfer material is used. The transfer process is repeated twice or more for one transfer material, and the image on the transfer material is exposed by the first transfer after the second exposure. It is a multiple transfer process in which the on-body images are sequentially superimposed in synchronization.
The surface layer of the photoconductor contains a fluorine-substituted resin powder, which is an electrophotographic photoconductor.

The surface energy of the photosensitive layer on which the fluororesin powder is uniformly dispersed can be remarkably lowered because the fluororesin powder exposes its low energy surface to the photoreceptor surface. Further, since the surface of the photoconductor having the low energy surface also contributes to the reduction of the contact energy with the cleaning blade, it is possible to reduce the load for driving the photoconductor.

Specific examples of the fluororesin powder include polymers such as tetrafluoroethylene, hexafluoropropylene, trifluoroethylene, chlorotrifluoroethylene, vinylidene fluoride, vinyl fluoride, perfluoroalkyl vinyl ether, and the like. Is used. The particle size of the fluororesin powder can be used in the range of 0.01 to 5 μm, and the molecular weight thereof is 3000 to 500.
It can be used in the range of 0000.

The fluororesin powder is dispersed as a photosensitive layer composition together with a binder resin. As a dispersing method, a sand mill, a ball mill, a roll mill, a homogenizer, a nanomizer, a paint shaker, an ultrasonic wave or the like is used. At the time of dispersion, a fluorinated surfactant, a graft polymer, a coupling agent or the like may be supplementarily used.

The content of the fluorine-based resin powder is preferably 4 to 70% by weight, more preferably 10 to 55% by weight in the outermost surface layer of the photoreceptor. If it is 4% by weight or less, the surface energy is insufficiently lowered, and if it is 70% by weight or more, the film strength of the surface layer is lowered.

As the binder resin for dispersing the fluororesin powder, polyester, polyurethane, polyarylate, polyethylene, polystyrene, polybutadiene,
Examples thereof include polycarbonate, polyamide, polypropylene, polyimide, polyamideimide, polysulfone, polyallyl ether, polyacetal, nylon, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin and butyral resin. Furthermore, reactive epoxy, (meth)
Acrylic monomers and oligomers can also be mixed and used after curing.

The photosensitive layer of the present invention has a single layer or a laminated structure. In the case of a single layer structure, generation and movement of photocarriers are carried out in the same layer, and the fluororesin powder of the present invention is contained in this layer which is the outermost surface layer. In the case of a laminated structure, a charge generation layer that generates photocarriers and a charge transport layer that moves carriers are laminated. The surface layer may be formed by either the charge generation layer or the charge transport layer. In any case, the fluororesin powder of the present invention is contained in the layer forming the outermost surface layer (Fig. 6). The single-layer photosensitive layer can have a thickness of 5 to 100 μm, more preferably 10 to 60 μm. The charge generation material and the charge transport material are contained in 20 to 80% by weight, and more preferably 30 to 70% by weight. In the laminated photoreceptor, the thickness of the charge generation layer is 0.001 to 6 μm.
m, more preferably 0.01 to 2 μm. The amount of the charge generating material is 10 to 100% by weight, more preferably 40 to
It is 100% by weight. The thickness of the charge transport layer is 5 to 100 μm
m, more preferably 10 to 60 μm. The amount of the charge transport material is 20 to 80% by weight, more preferably 30 to 70.
% By weight.

The charge generating material used in the present invention includes phthalocyanine pigments, polycyclic quinone pigments, azo pigments,
Perylene pigment, indigo pigment, quinacridone pigment, azurenium salt dye, squarylium dye, cyanine dye,
Pyrylium dyes, thiopyrylium dyes, xanthene dyes, quinoneimine dyes, triphenylmethane dyes, styryl dyes, selenium, selenium-tellurium, amorphous silicon, cadmium sulfide and the like can be mentioned.

Examples of the charge transport material used in the present invention include pyrene compounds, carbazole compounds, hydrazone compounds, N, N-dialkylaniline compounds, diphenylamine compounds, triphenylamine compounds, triphenylmethane compounds, pyrazoline compounds, styryl compounds,
Examples thereof include stilbene compounds.

In the electrophotographic photoreceptor of the present invention, a protective layer may be laminated on the photosensitive layer. The thickness of the protective layer is 0.01 to 2
0 μm is possible, more preferably 0.1 to 10 μm
Is. The protective layer may contain the above-mentioned charge generating material or charge transporting material, metal and its oxide, nitride, salt, alloy, and conductive material such as carbon. At this time, the fluororesin powder of the present invention is also included in the protective layer which is the outermost surface layer. As the binder resin used for the protective layer, polyester, polyurethane, polyarylate,
Polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, polyamideimide, polysulfone, polyallyl ether, polyacetal, nylon, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, butyral resin Etc. Furthermore, reactive epoxy and (meth) acrylic monomers and oligomers can be mixed and used after curing.

The conductive support used in the electrophotographic photosensitive member of the present invention is a metal or alloy of iron, copper, nickel, aluminum, titanium, tin, antimony, indium, lead, zinc, gold, silver, or the like. Oxides and carbon,
A conductive resin or the like can be used. The shape may be cylindrical, belt-like or sheet-like. In addition, the conductive material,
Sometimes it is molded, but it can be applied as paint,
You may vapor-deposit.

An undercoat layer may be provided between the conductive support and the photosensitive layer. The undercoat layer is mainly composed of a binder resin, but may contain the above-mentioned conductive material or acceptor.
As the binder resin forming the undercoat layer, polyester, polyurethane, polyarylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, polyamideimide, polysulfone, polyallyl ether, polyacetal, nylon, phenol resin, acrylic resin , Silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, butyral resin and the like.

As the method for producing the electrophotographic photosensitive member of the present invention, methods such as vapor deposition and coating are used. For coating, bar coater, knife coater, roll coater, attritor,
Spraying, dipping coating, electrostatic coating, powder coating and the like are used.

An electrophotographic apparatus according to the present invention is shown in FIG. Reference numeral 1 denotes a photoconductor drum, 2 denotes a transfer drum, and the photoconductor drum and the transfer drum may be driven in association with each other by gears, belts, or may have independent drive systems. In any case, the photoconductor drum and the transfer drum need to overlap the images of the first and second colors at the time of transfer, and control for synchronization is performed. This electrophotographic device can be used as an output device for a copying machine, a printer, a facsimile, or the like.

The image forming process is basically performed in the order of charging, exposure, development, transfer, cleaning, and charge removal, and by repeating these in sequence, color superposition is performed to reproduce a color image. First, after charging the surface of the photoconductor with a charging device 3 such as a corotron or a scorotron, information processing such as a reading device or a computer, a storage medium 4 is performed.
A light source 5 such as a laser, an LED, or a liquid crystal shutter, which is controlled by a digital image signal sent from the device, irradiates a dot-shaped minute optical image on the photoconductor. The optical image generates charge carriers in the photoconductor to erase the surface charge of the photoconductor to form a dot-shaped minute electrostatic latent image. The image signal is color separated into three colors of cyan, magenta and yellow, or four colors obtained by adding black to them, and after electrostatic latent images corresponding to the respective colors are formed,
Development is sequentially performed by the developing device 6 corresponding to each color.
The three-color or four-color developing device is arranged in a fixed manner (FIG. 2) arranged side by side with respect to the photoconductor, laterally moved (FIG. 3), vertically moved (FIG. 4), or rotationally moved (FIG. 1) to sequentially expose the photosensitive material. There is a movement method that contacts the body.

The image developed by the developer is transferred to a transfer material such as transfer paper in a transfer process. The transfer material is electrostatically or mechanically fixed to the surface of the transfer drum 2 in order to transfer the images of three colors or four colors in a multiple manner on one transfer material. Further, the image starting point and the image area of the photoconductor drum 1 and the transfer drum 2 are controlled in synchronization at least during the multiple transfer process of the same image onto the same transfer material so that the images of the respective colors are not displaced during the multiple transfer. To be done. To transfer the developer from the photoconductor onto the transfer material, a corotron, a scorotron, a conductive brush, a conductive roller or the like 7 is mainly used due to an electrostatic force having a polarity opposite to that of the developer. At the same time, a pressure member may be used together to impart a transfer effect by pressure. In order to support the transfer material, the transfer drum 2 is generally formed by stretching a film, a mesh or the like in a cylindrical shape on a cylindrical frame. The film and mesh materials are polyethylene terephthalate, polyester, polysulfone,
Various resins such as polyarylate, polyphenylene oxide, polyimide, polyamide, nylon, polyethylene oxide, polystyrene and polyacetal, and polymer alloys containing them are used. Also film,
The mesh may include a conductive material such as metal, metal oxide, carbon, and conductive polymer.

The residual developer after transfer is removed by cleaning 8. As a cleaning method, it is desirable to adopt blade cleaning in order to realize a simpler device configuration in association with space saving of the device.
The blade cleaning has a simple configuration in which an elastic member such as a plate-shaped polyurethane is merely abutted on the photoconductor in the generatrix direction. The abutting direction of the blade cleaning is a forward direction in which the blade tip is oriented in the rotation direction of the photoconductor, a counter direction in which the blade tip is oriented in the direction opposite to the rotation direction of the photoconductor, and a case where the photoconductor and the blade are vertical, etc. There is. Further, the blade is not limited to a single blade, but a plurality of blades can be used together. Further, a cleaning brush, a web, a magnetic brush or the like may be used in combination as an auxiliary.

[0026]

EXAMPLES Next, specific examples of the present invention will be shown below.

Example 1 10 parts by weight of conductive titanium oxide (tin oxide coat, average primary particle size 0.4 μm), 10 parts by weight of phenol resin precursor (resole type), 10 parts by weight of methanol, and 10 parts by weight of butanol. Was dispersed in a sand mill, dip-coated in an aluminum cylinder having an outer diameter of 80 mm and a length of 360 mm and cured at 140 ° C., and then a conductive layer having a volume resistance of 5 × 10 ⁹ Ωcm and a thickness of 20 μm was provided.

Next, 10 parts by weight of the following methoxymethylated nylon (degree of methoxymethylation is about 30%):

[0029]

[Chemical 1] And 150 parts by weight of isopropanol were mixed and dissolved, and then dip-coated on the conductive layer to form an undercoat layer of 1 μm.

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

[0031]

[Chemical 2] Polycarbonate resin (bisphenol A, molecular weight 30
000) 5 parts by weight and 700 parts by weight of cyclohexanone were dispersed in a sand mill, and this dispersion was dip-coated on the undercoat layer to obtain a charge generation layer of 0.05 μm.

Next, 10 parts by weight of the following triphenylamine,

[0033]

[Chemical 3] Polycarbonate resin (bisphenol Z, molecular weight 20
000) 10 parts by weight, 50 parts by weight of monochlorobenzene,
And 15 parts by weight of dichloromethane were mixed by stirring, and then dip-coated on the charge generation layer. The coated cylinder was dried with hot air to form a 20 μm charge transport layer.

Next, polytetrafluoroethylene resin fine powder (emulsion polymerization fine powder, average particle size 0.27 μm)
m, molecular weight about 300000) 1 part by weight, polycarbonate resin (bisphenol Z, molecular weight 80000) 6 parts by weight, monochlorobenzene 120 parts by weight, and dichloromethane 80 parts by weight were dispersed and mixed in a sand mill. To this, 3 parts by weight of the triphenylamine (1) was added, mixed and dissolved, and spray-coated on the charge-transporting layer to provide a protective layer of 5 μm to obtain a photosensitive drum.

[Comparative Example 1] In the photoreceptor of Example 1,
The photoconductor coated with the charge transport layer without the protective layer was used as the photoconductor drum of Comparative Example 1.

[Contact Angle] The contact angle of pure water on the surface of the photosensitive drum was compared by a dropping type contact angle meter. As a result, the contact angle of the photoreceptor of Example 1 showed a large value of 110 degrees and a low energy surface was realized, whereas Comparative Example 1 had a contact angle of 80 degrees and a low energy surface was not obtained. It was

[Transfer Efficiency] Each photoconductor was set in the apparatus shown in FIG. 1 and the initial transfer efficiency was measured. A negative polarity scorotron was used for charging, and a laser having a wavelength of 787 nm was used for exposure. A two-component negative polar developer was used as the developer, and transfer was performed with a corotron having a positive polarity through a polyethylene terephthalate film having a thickness of 100 μm.
The transfer efficiency was calculated after measuring the density of the developer transferred to the transfer material and the density of the developer remaining on the photoconductor with a reflection type Macbeth densitometer when the halftone solid pattern was output in a single color. . The image density of the halftone solid pattern was set to 0.80 by the reflection type Macbeth density measurement on the transfer material. In Example 1, the transfer efficiency was as high as 93%, whereas in Comparative Example 1, the transfer efficiency was as low as 86%. It was also found that the measured value of the contact angle had a correlation with the actual transfer efficiency, and the transfer efficiency was found to increase as the surface energy decreased.

[Transfer unevenness] The photosensitive drum was put into the apparatus shown in FIG. 1 and a halftone solid pattern image after four-color multiple transfer was output. Image output is initial and 10
Two kinds after the continuous output of 00 sheets were output as samples. The image density of the halftone solid pattern image was 1.20 on average with a reflection type Macbeth densitometer. The output image is
The transfer unevenness was evaluated by measuring the uniformity of image density using a reflection type Macbeth densitometer and calculating the deviation width from the average image density. The measuring points were 100 points within a frame of 10 cm ² . In Example 1, the transfer unevenness was 3.2% at the initial stage and 4.7% after 1000 sheets, and the image was substantially uniform even to human eyes. On the other hand, Comparative Example 1 has an initial value of 4.0.
%, The image was almost uniform, but after 1000 sheets it was 1
The transfer unevenness was aggravated at 0.3%, and it looked like a non-uniform image with a lot of rattling even to human eyes. Further, when the transfer unevenness exceeds 5%, it was clearly recognized as a nonuniform image by human eyes. As shown by the above results, the reduction of the surface energy was effective for the transfer unevenness as well as the transfer efficiency.

[Transmission void] The above-mentioned photosensitive drum was put into the apparatus shown in FIG. 1 and a character pattern image after four-color multiple transfer was output. The image was output by using the image after continuous output of 1000 sheets as a sample. The photoreceptor of Example 1 has 1000
A uniform character pattern was also obtained in the character pattern after printing, but in the photoconductor of Comparative Example 1, a portion other than the outline of the character pattern was omitted due to improper transfer. An enlarged photograph of the character pattern is shown in FIG. As shown by the above results, the reduction of the surface energy was effective not only in the transfer efficiency but also in the voids in the transfer.

[Driving Pitch Unevenness] The photosensitive drum was loaded into the apparatus shown in FIG. 1 to output a halftone solid pattern image after four-color multiple transfer. Image output is 100
An image after continuously outputting 0 sheets was used as a sample. The photosensitive member of Example 1 obtained a uniform pattern even in the halftone solid pattern after 1000 sheets, but the photosensitive member of Comparative Example 1 had an irregular horizontal direction in the bus line direction of the photosensitive drum of the halftone solid pattern. Streaky pitch unevenness occurred. It is also known that the pitch unevenness in Comparative Example 1 is eliminated by releasing the cleaning blade of the apparatus shown in FIG. 1 from the photosensitive drum to bring it into non-contact, and the contact energy between the photosensitive drum and the cleaning blade is involved. It is believed that Therefore, it has been found that the photoconductor of the present invention reduces the contact energy between the photoconductor drum and the cleaning blade by reducing the surface energy, and also reduces the driving load such as pitch unevenness.

[Color Misregistration] The photosensitive drum was loaded into the apparatus shown in FIG. 1 and a gray halftone solid pattern image after four-color multiple transfer was output. Image output is 1000
The image after continuous output was used as a sample. The photoreceptor of Example 1 obtained a uniform color tone pattern even in the gray halftone solid pattern after 1000 sheets were printed, but Comparative Example 1
With respect to the photoconductor of No. 3, the gray halftone solid pattern had partial reddish color unevenness. When this output image is observed under a microscope, in a dot-shaped image in which four-color dots are overlapped by four-color multiple transfer, color tone unevenness occurs in a portion of the four colors where the magenta image is shifted by 50 to 90 μm, and microscopic color It turned out that the gap was the cause. It is also known that the color misregistration seen in Comparative Example 1 is eliminated by releasing the cleaning blade of the apparatus shown in FIG. 1 from the photoconductor drum and bringing it out of contact, and the contact energy between the photoconductor drum and the cleaning blade is Probably involved. Therefore, it has been found that the photoconductor of the present invention reduces the contact energy between the photoconductor drum and the cleaning blade by reducing the surface energy, and also reduces the driving load that causes color misregistration.

[Example 2] Aluminum cylinder, conductive layer,
The same layers as in Example 1 were prepared up to the undercoat layer and the charge generation layer.

Next, the triphenylamine (1) 10
Parts by weight, polycarbonate resin (bisphenol Z, molecular weight 20000) 10 parts by weight, monochlorobenzene 50
After stirring and mixing 15 parts by weight of dichloromethane and 15 parts by weight of dichloromethane, the charge generation layer was dip-coated. The coated cylinder was dried with hot air to form a 20 μm charge transport layer.

Next, polytetrafluoroethylene resin fine powder (emulsion polymerization fine powder, average particle size 0.27 μm)
m, molecular weight about 300,000) 3 parts by weight, polycarbonate resin (bisphenol Z, molecular weight 80,000) 5.5
By weight, 120 parts by weight of monochlorobenzene and 80 parts by weight of dichloromethane were dispersed and mixed in a sand mill. To this, 2.5 parts by weight of the triphenylamine (1) was added, mixed and dissolved, and spray-coated on the charge-transporting layer to form a protective layer of 6 μm, and the photosensitive drum of Example 2 was obtained.

The contact angle of this photoconductor with pure water is 11
It was 5 ° and the surface energy was sufficiently low. Further, when this photosensitive member was put into the apparatus shown in FIG. 1 and the transfer efficiency was measured, it showed a good value of 95%. The transfer unevenness was 3.0% at the initial stage and 4.3% after outputting 1000 sheets. Similarly, good results were also obtained for voids in transfer.

When the apparatus shown in FIG. 1 was also examined for driving pitch unevenness and color misregistration, good results were obtained.

[Example 3] Aluminum cylinder, conductive layer,
The same layers as in Example 1 were prepared up to the undercoat layer and the charge generation layer.

Next, 3 parts by weight of the triphenylamine (1), 7 parts by weight of the following triphenylamine,

[0049]

[Chemical 4] Polycarbonate resin (bisphenol Z, molecular weight 20
000) 10 parts by weight, 50 parts by weight of monochlorobenzene, and 15 parts by weight of dichloromethane were mixed by stirring, and then dip-coated on the charge generation layer. The coated cylinder was dried with hot air to form a 20 μm charge transport layer.

Next, polytetrafluoroethylene resin fine powder (emulsion polymerization fine powder, average particle size 0.27 μm)
m, molecular weight about 300,000) 3 parts by weight, polycarbonate resin (bisphenol Z, molecular weight 80,000) 5.5
By weight, 120 parts by weight of monochlorobenzene and 80 parts by weight of dichloromethane were dispersed and mixed in a sand mill. To this, 2.5 parts by weight of the triphenylamine (2) was added, mixed and dissolved, and applied onto the charge transport layer by spray coating to provide a 6 μm protective layer to obtain the photosensitive drum of Example 3.

The contact angle of this photoconductor with pure water is 11
It was 6 ° and the surface energy was sufficiently low. Further, when this photoconductor was put into the apparatus shown in FIG. 1 and the transfer efficiency was measured, a good value of 94% was shown. The transfer unevenness was as good as 3.1% at the initial stage and 4.5% after outputting 1000 sheets. Similarly, good results were also obtained for voids in transfer.

When the apparatus shown in FIG. 1 was examined for driving pitch unevenness and color misregistration, good results were obtained.

[Example 4] Aluminum cylinder, conductive layer,
The same layers as in Example 1 were prepared up to the undercoat layer and the charge generation layer.

Next, 3 parts by weight of the triphenylamine (1), 7 parts by weight of the triphenylamine (2), a polycarbonate resin (bisphenol Z, molecular weight 2000)
0) 10 parts by weight, 50 parts by weight of monochlorobenzene, and 15 parts by weight of dichloromethane were mixed by stirring, and then dip-coated on the charge generation layer. The coated cylinder was dried with hot air to form a 20 μm charge transport layer.

Next, polytetrafluoroethylene resin fine powder (emulsion polymerization fine powder, average particle size 0.27 μm)
m, molecular weight about 300000) 4 parts by weight, polycarbonate resin (bisphenol Z, molecular weight 80000) 4 parts by weight, monochlorobenzene 120 parts by weight, and dichloromethane 80 parts by weight were dispersed and mixed in a sand mill. To this, 2 parts by weight of the triphenylamine (2) was added, mixed and dissolved, and spray-coated on the charge-transporting layer to form a protective layer of 5 μm, and the photosensitive drum of Example 4 was obtained.

The contact angle of this photoconductor with pure water is 11
It was 7 ° and the surface energy was sufficiently low. Further, when this photoreceptor was put into the apparatus shown in FIG. 1 and the transfer efficiency was measured, it showed a good value of 96%. The transfer unevenness was good at 2.7% in the initial stage and 4.2% after outputting 1000 sheets. Similarly, good results were also obtained for voids in transfer.

When the apparatus shown in FIG. 1 was also examined for driving pitch unevenness and color misregistration, good results were obtained.

[Embodiment 5] Aluminum cylinder, conductive layer,
The same layers as in Example 1 were prepared up to the undercoat layer and the charge generation layer.

Next, 3 parts by weight of the triphenylamine (1), 7 parts by weight of the triphenylamine (2), a polycarbonate resin (bisphenol A, molecular weight 2500)
0) 10 parts by weight, 50 parts by weight of monochlorobenzene, and 15 parts by weight of dichloromethane were mixed by stirring, and then dip-coated on the charge generation layer. The coated cylinder was dried with hot air to form a 20 μm charge transport layer.

Next, polytetrafluoroethylene resin fine powder (emulsion polymerization fine powder, average particle size 0.27 μm)
m, molecular weight about 300,000) 3 parts by weight, polycarbonate resin (bisphenol A, molecular weight 100,000) 5.
5 parts by weight, 120 parts by weight of monochlorobenzene, and 80 parts by weight of dichloromethane were dispersed and mixed in a sand mill.
To this, 2.5 parts by weight of the triphenylamine (2) was added, mixed and dissolved, and applied by spray coating on the charge transport layer to form a protective layer of 5 μm to obtain a photosensitive drum of Example 5.

The contact angle of this photoconductor with pure water is 11
It was 3 ° and the surface energy was sufficiently low. Further, when this photoreceptor was put into the apparatus shown in FIG. 1 and the transfer efficiency was measured, it showed a good value of 93%. The transfer unevenness was good at 3.4% at the initial stage and 4.5% after outputting 1000 sheets. Similarly, good results were also obtained for voids in transfer.

When the driving pitch unevenness and the color shift were examined with the apparatus shown in FIG. 1, good results were obtained.

[Embodiment 6] Aluminum cylinder, conductive layer,
The same layers as in Example 1 were prepared up to the undercoat layer and the charge generation layer.

Next, polytetrafluoroethylene resin fine powder (emulsion polymerization fine powder, average particle size 0.27 μm)
m, molecular weight about 300000) 2 parts by weight, polycarbonate resin (bisphenol Z, molecular weight 25000) 5 parts by weight, monochlorobenzene 20 parts by weight, and dichloromethane 15 parts by weight were dispersed and mixed in a sand mill. to this,
5 parts by weight of the triphenylamine (2) was added, mixed and dissolved, and applied on the charge generation layer by dip coating to give 25 μm.
A photoconductor drum of Example 6 was prepared by providing a charge transport layer of m.

The contact angle of this photoreceptor with pure water is 10
It was 7 ° and the surface energy was sufficiently low. Further, when this photoconductor was put into the apparatus shown in FIG. 1 and the transfer efficiency was measured, it showed a good value of 90%. The transfer unevenness was 3.7% at the initial stage and 4.9% after outputting 1000 sheets. Similarly, good results were also obtained for voids in transfer.

When the apparatus shown in FIG. 1 was examined for driving pitch unevenness and color misregistration, good results were obtained.

Example 7 Aluminum cylinder, conductive layer,
The same layers as in Example 1 were prepared up to the undercoat layer and the charge generation layer.

Next, the triphenylamine (2) 10
Parts by weight, polycarbonate resin (bisphenol Z, molecular weight 25000) 10 parts by weight, monochlorobenzene 50
After stirring and mixing 15 parts by weight of dichloromethane and 15 parts by weight of dichloromethane, the charge generation layer was dip-coated. The coated cylinder was dried with hot air to form a 20 μm charge transport layer.

Next, polyhexafluoropropylene resin fine powder (emulsion polymerization fine powder, average particle size 0.39)
μm, molecular weight about 500,000) 3 parts by weight, polycarbonate resin (bisphenol Z, molecular weight 100,000)
5.5 parts by weight, 120 parts by weight of monochlorobenzene, and 80 parts by weight of dichloromethane were dispersed and mixed in a sand mill. To this, 2.5 parts by weight of the triphenylamine (2) was added, mixed and dissolved, and applied by spray coating on the charge transport layer to provide a protective layer of 5 μm to obtain a photosensitive drum of Example 7.

The contact angle of this photoconductor with pure water is 11
It was 5 ° and the surface energy was sufficiently low. Further, when this photoreceptor was put into the apparatus shown in FIG. 1 and the transfer efficiency was measured, it showed a good value of 93%. The transfer unevenness was 3.0% at the initial stage and 4.3% after outputting 1000 sheets. Similarly, good results were also obtained for voids in transfer.

When the driving pitch unevenness and the color shift were examined with the apparatus shown in FIG. 1, good results were obtained.

[Comparative Example 2] Aluminum cylinder, conductive layer,
The same layers as in Example 1 were prepared up to the undercoat layer and the charge generation layer.

Next, polytetrafluoroethylene resin fine powder (emulsion polymerization fine powder, average particle size 0.27 μm)
m, molecular weight about 300,000) 0.4 parts by weight, polycarbonate resin (bisphenol Z, molecular weight 25,000) 5
By weight, 20 parts by weight of monochlorobenzene and 15 parts by weight of dichloromethane were dispersed and mixed in a sand mill. To this, 5 parts by weight of the triphenylamine (2) was added, mixed and dissolved, and coated on the charge generation layer by dip coating.
A photoconductor drum of Comparative Example 2 was prepared by providing a charge transport layer having a thickness of 5 μm.

The contact angle of this photoconductor with pure water is 85.
The surface energy was high. Further, when this photoreceptor was put into the apparatus shown in FIG. 1 and the transfer efficiency was measured, it was not good at 83%. The transfer unevenness was 4.1% at the initial stage and 9.8% after outputting 1000 sheets, which was not good.
Similarly, a satisfactory result was not obtained with respect to voids in transfer.

When the driving pitch unevenness and the color shift were examined by the apparatus shown in FIG. 1, satisfactory results were not obtained.

[Comparative Example 3] Aluminum cylinder, conductive layer,
The same layers as in Example 1 were prepared up to the undercoat layer and the charge generation layer.

Next, the triphenylamine (1) 10
Parts by weight, polycarbonate resin (bisphenol Z, molecular weight 25000) 10 parts by weight, monochlorobenzene 50
After stirring and mixing 15 parts by weight of dichloromethane and 15 parts by weight of dichloromethane, the charge generation layer was dip-coated. The coated cylinder was dried with hot air to form a 20 μm charge transport layer.

Next, 6 parts by weight of a polycarbonate resin (bisphenol Z, molecular weight 100,000), 3 parts by weight of the above triphenylamine (1), and monochlorobenzene 120.
Parts by weight and 80 parts by weight of dichloromethane are added, mixed and dissolved, and spray-coated to form the charge-transporting layer.
A photoconductor drum of Comparative Example 3 was provided with a protective layer having a thickness of μm.

The contact angle of this photoconductor with pure water is 85.
The surface energy was high. Further, when this photoconductor was put into the apparatus shown in FIG. 1 and the transfer efficiency was measured, it was not good at 80%. The transfer unevenness was 4.2% at the initial stage and 10.9% after outputting 1000 sheets, which was not good. Similarly, a satisfactory result was not obtained with respect to voids in transfer.

When the driving pitch unevenness and the color shift were examined with the apparatus shown in FIG. 1, satisfactory results were not obtained.

[0081]

[Table 1]

[0082]

The electrophotographic photosensitive member of the present invention realizes an electrophotographic photosensitive member having a high transfer efficiency and a small driving load on the photosensitive member by significantly lowering the surface energy as compared with the conventional one. This makes it possible to provide a high-quality image free from image defects such as transfer unevenness, voids in transfer, drive pitch unevenness, and color misregistration, especially in an electrophotographic apparatus using a multiple transfer process.

[Brief description of drawings]

FIG. 1 is an example of a schematic configuration diagram of an electrophotographic apparatus using a multiple transfer process.

FIG. 2 is an example of a schematic configuration diagram of an electrophotographic apparatus using a multiple transfer process.

FIG. 3 is an example of a schematic configuration diagram of an electrophotographic apparatus using a multiple transfer process.

FIG. 4 is an example of a schematic configuration diagram of an electrophotographic apparatus using a multiple transfer process.

FIG. 5 is an example of a void image in transfer.

FIG. 6 is a schematic diagram showing a configuration of a photoconductor.

[Explanation of symbols]

1 Photoreceptor Drum 2 Charging Device 3 Reading Device, Information Processing Device, Storage Device, Communication Device, etc. 4 Light Source 5 Developer 6 Original 7 Transfer Charging 8 Cleaning Device 9 Eliminating 10 Fixing 11 Paper Feeding 21 Conductive Support 22 Conductive Layer 23 Undercoat layer 24 Charge generation layer 25 Charge transport layer 26 Protective layer 27 Single-layer photosensitive layer 28 Fluorine-substituted resin powder

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaaki Yamagami 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Shoji Amamiya 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Issei Nakamura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (10)

[Claims] 1. An electrophotographic photosensitive member used in an electrophotographic apparatus for forming an image on a transfer material through at least charging, exposing, developing, transferring and cleaning steps, wherein the transferring step is synchronized with a single photosensitive member. The transfer process is performed by a transfer material supporting member that supports the material, the transfer process is repeated twice or more for one transfer material, and the image on the transfer material after the second transfer is transferred to the image on the transfer material by the first transfer. An electrophotographic photosensitive member, which is a multiple transfer process in which layers are sequentially superposed in synchronization with each other, and a surface layer of the photosensitive member contains a fluorine-substituted resin powder. 2. The electrophotographic photosensitive member according to claim 1, wherein the exposure step is a step of forming a dot-shaped electrostatic latent image by dot-shaped exposure. 3. The multiple transfer step transfers a dot-shaped image formed by developing a dot-shaped electrostatic latent image on a photoconductor, and a second transfer to a dot image on a transfer material by the first transfer. 2. The electrophotographic photosensitive member according to claim 1, which is a subsequent step of sequentially superimposing dot images on the photosensitive member in synchronization. 4. The electrophotographic photosensitive member according to claim 1, wherein the cleaning step includes at least a cleaning step using a blade. 5. The exposure spot diameter on the dot is 12
The electrophotographic photosensitive member according to claim 1, which has a thickness of 0 μm or less. 6. The electrophotographic photosensitive member according to claim 1, wherein the surface layer containing the fluorine-substituted resin powder further contains a polycarbonate resin. 7. The electrophotographic photosensitive member according to claim 1, wherein the fluorine-containing resin powder has a fluorine content of 30% by weight or more and 90% by weight or less. 8. The electrophotographic photosensitive member according to claim 1, wherein the surface layer containing the fluorine-substituted resin powder further contains a charge transport material. 9. The electrophotographic photosensitive member according to claim 1, wherein the surface layer containing the fluorine-substituted resin powder is a layer provided as a protective layer after a charge generation layer and a charge transport layer are sequentially laminated. 10. At least charging, exposure, development, transfer,
In an electrophotographic apparatus that forms an image on a transfer material through a cleaning step, the transfer step is performed by a transfer material support member that supports the transfer material in synchronization with a single photoreceptor.
The transfer step is a multiple transfer step in which the transfer step is repeated two or more times for one transfer material, and the images on the photoconductor after the second time are sequentially superimposed in synchronization with the image on the transfer material by the first transfer. An electrophotographic apparatus using an electrophotographic photosensitive member in which the surface layer of the photosensitive member contains a fluorine-substituted resin powder.