JP4887969B2 - Organic photoreceptor, image forming apparatus using the organic photoreceptor, and process cartridge - Google Patents

Description

  The present invention relates to an organic photoreceptor used for electrophotographic image formation, and more specifically, an organic photoreceptor used for electrophotographic image formation used in the field of copying machines and printers, and the organic photoreceptor used. The present invention relates to an image forming apparatus and a process cartridge.

Organic using a coating solution in which fluororesin fine particles such as PTFE (polytetrafluoroethylene) are dispersed in an organic photoreceptor layer used for electrophotographic image formation in order to improve releasability and durability. Photoreceptor technology is publicly available. (Patent Document 1)
However, it is difficult to uniformly disperse the fluorine-containing resin fine particles in the surface layer of the photoreceptor, and the effect of releasing properties of the fluorine-containing resin fine particles cannot be sufficiently exhibited.

  In particular, when the fluorine-containing resin fine particles are contained at a high concentration in order to improve the releasability of the protective layer (surface layer) of the photoreceptor, the content of the fluorine-containing resin fine particles is reduced near the surface of the protective layer. In the photoconductor in the initial stage of use, the transfer rate of the toner image is not improved, and voids are likely to occur or image defects due to poor toner cleaning are likely to occur.

  In addition, when the fluorine-containing resin fine particles are contained at a high concentration, there is a problem that the protective layer is likely to have agglomerated particles of the fluorine-containing resin fine particles, the film quality of the protective layer is deteriorated, and scratches are likely to occur. is doing.

On the other hand, as an electrophotographic image process, a cleanerless image forming method that does not use a cleaning device is known. In this cleaner-less process, even when a photoconductor containing fluororesin fine particles having a good toner transfer rate is used, the transfer rate of the toner image is not improved with the photoconductor in the initial stage of use as described above. In other words, there are problems such as the occurrence of voids and image defects due to poor toner cleaning.
JP-A-5-45920

  The inventors of the present application aim to solve the technical problem of the organic photoreceptor containing the fluorine-containing resin fine particles as described above, and the dispersion of the fluorine-containing resin fine particles contained in the protective layer is not uniform. The present invention is to provide an organic photosensitive member that improves transferability, solves transfer defects and cleaning defects at the time of initial use of the photosensitive member, and is less likely to cause scratches. An image forming apparatus and a process cartridge using the organic photosensitive member are provided. Is to provide.

As a result of intensive studies to overcome the above-described problems of the present invention, the present inventors have determined the content of the fluororesin fine particles in the vicinity of the surface of the protective layer containing the fluororesin fine particles. The inventors have found that it is effective to bring the content of the fluororesin fine particles closer to the average and to reduce the aggregation of the fluororesin fine particles, thereby completing the present invention. That is, the object of the present invention is achieved by having the following configuration.
1. The electrically conductive substrate, the organic photosensitive member having an intermediate layer between the photosensitive layer and the coercive Mamoruso, the protective layer contains a fluorine-containing resin fine particles, the area ratio of the fluororesin particles of the protective layer A1, A2 And A3 satisfies the following relationship:

0.3 ≧ A2 ≧ 0.02
A2> A1 ≧ A2 × 0.5
1.0> A3 / A2 ≧ 0.5
However,
A1; area ratio A2 of fluororesin particles present in the protective layer up to a depth 0.5μm from the surface; area ratio of the fluororesin particles present in the protective layer from the surface up to a depth 3.0 [mu] m A3; 1. Area ratio of isolated fluororesin fine particles present in the protective layer from the surface to a depth of 3.0 μm 2. The organophotoreceptor according to 1 above, wherein the fluororesin fine particles have a number average primary particle size of less than 0.2 μm.
3. 3. The organophotoreceptor according to 1 or 2 above, wherein the protective layer is applied using a quantity-regulating coater.
4). 4. The organophotoreceptor as described in 3 above, wherein the amount-regulating coater is a circular slide hopper coater.
5. In a cleanerless image forming apparatus having an organic photoconductor, a charging unit, an exposure unit, a developing unit, and a transfer unit, and collecting a toner image remaining on the organic photoconductor by the developing unit, the organic photoconductor An organic photoreceptor having an intermediate layer, a photosensitive layer and a protective layer on a conductive support, the protective layer containing fluorine-containing resin fine particles, and the area ratio A1 of the fluorine-containing resin fine particles in the protective layer; An image forming apparatus, wherein A2 and A3 satisfy the following relationship.

0.3 ≧ A2 ≧ 0.02
A2> A1 ≧ A2 × 0.5
1.0> A3 / A2 ≧ 0.5
However,
A1; area ratio A2 of fluororesin particles present in the protective layer up to a depth 0.5μm from the surface; area ratio of the fluororesin particles present in the protective layer from the surface up to a depth 3.0 [mu] m A3; 5. Area ratio of isolated fluororesin fine particles present in the protective layer from the surface to a depth of 3.0 μm In a process cartridge used in a cleaner-less image forming apparatus having an organic photoconductor, a charging device, an exposure device, a developing device, and a transfer device, and collecting a toner image remaining on the organic photoconductor with a developing device. The organic photoreceptor is an organic photoreceptor having an intermediate layer, a photosensitive layer, and a protective layer on a conductive support, the protective layer containing fluorine-containing resin fine particles, and the fluorine-containing resin fine particles in the protective layer The area ratios A1, A2 and A3 satisfy the following relationship, and at least one of the organic photoreceptor and the charging unit, the exposure unit, the developing unit, and the transfer unit is integrally configured so that it can be taken in and out of the image forming apparatus. A process cartridge characterized by comprising.

0.3 ≧ A2 ≧ 0.02
A2> A1 ≧ A2 × 0.5
1.0> A3 / A2 ≧ 0.5
However,
A1; area ratio A2 of fluororesin particles present in the protective layer up to a depth 0.5μm from the surface; area ratio of the fluororesin particles present in the protective layer from the surface up to a depth 3.0 [mu] m A3; Area ratio of isolated fluororesin fine particles present in the protective layer from the surface to a depth of 3.0 μm

  By using an organic photoreceptor in which the dispersion non-uniformity of the fluororesin fine particles contained in the protective layer of the present invention is improved, transfer defects and cleaning defects at the initial use of the photoreceptor are solved, and scratches are prevented. An electrophotographic image can be provided, and an image forming apparatus and a process cartridge using the organic photoreceptor can be provided.

  Hereinafter, the present invention will be described in detail.

The organic photoreceptor of the present invention, on the electrically conductive substrate, the organic photosensitive member having an intermediate layer between the photosensitive layer and the coercive Mamoruso, the protective layer contains a fluorine-containing resin fine particles, fluorine-containing of the protective layer The area ratios A1, A2 and A3 of the resin fine particles satisfy the following relationship.

0.3 ≧ A2 ≧ 0.02
A2> A1 ≧ A2 × 0.5
1.0> A3 / A2 ≧ 0.5
However,
A1; area ratio A2 of fluororesin particles present in the protective layer up to a depth 0.5μm from the surface; area ratio of the fluororesin particles present in the protective layer from the surface up to a depth 3.0 [mu] m A3; Area ratio of isolated fluorine-containing resin fine particles existing in a protective layer having a depth of 3.0 μm from the surface. The organic photoreceptor of the present invention has the above-described configuration, so that transfer defects and cleaning at the initial use of the photoreceptor can be achieved. It is possible to provide an electrophotographic image in which defects are resolved and scratches are prevented.

  In addition, the area ratio of each fluororesin fine particle from the said surface can measure the cross-sectional image of a protective layer using a high-resolution transmission electron microscope (HR-TEM). Here, the area ratio of the entire cross-sectional area of the measurement target is set to 1.0000.

Specifically, a small piece of each sample was covered and hardened with a resin in which an epoxy resin was mixed with a curing agent and an accelerator, and a section with a cross-section was prepared with a microtome to obtain a sample for observation. The cross section of the obtained sample was photographed at a magnification of 20,000 using a transmission electron microscope, and the photographed protective layer cross-sectional area was 100 cm ² (the length in the cross-sectional direction of the protective layer cross section (the length photographed at a magnification of 20,000). A1, A2, and A3 can be obtained by taking out the area of the fluorine-containing resin fine particles in () × horizontal length) from the image information and performing arithmetic processing. If the area occupied by the fluororesin fine particles is 50 cm ² , the area ratio is 0.5. A3 is the area ratio of only the isolated fluororesin fine particles that are not aggregated.

  The transmission electron microscope apparatus uses JEM-2000FX (manufactured by JEOL). A1, A2, and A3 were calculated by performing arithmetic processing on the photographed image information with an image processing apparatus “Luzex F” (manufactured by Nireco Corporation) provided in the electron microscope apparatus.

  In the relational expression of A1, A2, and A3, when A2 is larger than 0.3, the protective layer is easily damaged, and stripes are likely to occur in the halftone image. On the other hand, when A2 is smaller than 0.02, the releasing effect of the entire protective layer is reduced, the transferability of the toner image is deteriorated, and the void is likely to occur. A2 is 0.3 ≧ A2 ≧ 0.02, but a range of 0.25 ≧ A2 ≧ 0.10 is more preferable.

  A1 is in the range of A2> A1 ≧ A2 × 0.5. However, in the vicinity of the surface of the protective layer, the fluorine-containing resin fine particles are reduced in area ratio and become binder-rich in the coating and drying process. No phenomenon exceeding A2 occurs. On the other hand, if A1 is smaller than A2 × 0.5, the transferability of the toner image is deteriorated, and the void is likely to occur.

  A3 / A2 is an expression indicating the degree of dispersion of the fluororesin fine particles. The larger the value, the less the cohesiveness of the fluororesin fine particles and the better the dispersibility. A3 / A2 is 1.0> A3 / A2 ≧ 0.5, but if it is smaller than 0.5, the dispersibility of the fluororesin fine particles in the protective layer is poor, and streaks are likely to occur in the halftone image. .

As the method for achieving the area ratio of the fluororesin fine particles in the protective layer, the following conditions (a) and (b) are particularly important.
(A) A coating solution in which fluorine-containing resin fine particles having a number average primary particle size of less than 0.2 μm are used as the fluorine-containing resin fine particles to be contained in the protective layer, and the fluorine-containing resin fine particles are dispersed to a substantially average primary particle size. To produce a protective layer, to make the distribution of fluororesin fine particles uniform in the protective layer coating stage,
(B) after application of the protective layer, to ease the uneven distribution of the fluororesin fine particles that are likely to occur in the drying process by delaying the drying immediately after application,
Hereinafter, (a), (b) and related matters will be described ((b) will be described with reference to FIG. 5).

  In order to prepare a coating liquid using fluorine-containing resin fine particles having a number average primary particle size of less than 0.2 μm and dispersing the fluorine-containing resin fine particles to an average average primary particle size, the fluorine-containing resin mixed in the solution is used. The step of dispersing the fine particles by liquid collision under high pressure and the filtration step are circulated a plurality of times to disperse the fluororesin fine particles.

  The above-described step of dispersing by high-pressure liquid collision according to the present invention (hereinafter simply referred to as high-pressure liquid collision dispersion step) generates a high-speed flow by any method and causes liquids to collide with each other. In addition, it is a collective term for devices equipped with the function of promoting emulsification and dispersion by effectively utilizing the turbulent flow, shearing, and cavitation effects caused by high-speed flow and atomizing the material to be treated (dispersoid) in the liquid. As such a liquid collision dispersion device under high pressure, there is a high-pressure homogenizer. Specifically, a liquid to be treated is pumped into a narrow flow path such as an orifice by a plunger pump or a rotary pump and injected. The liquids to be processed are collided from the front. The turbulent flow and the shearing action that occur when the liquids to be treated collide with each other cause crushing from the inside of the dispersoid, and the dispersoid in the liquid to be treated is remarkably atomized.

  As such a liquid collision dispersion device under high pressure, a type using a high-speed injection by a valve plate marketed as a “high pressure homogenizer” (APV Gorin, Runny, Soabi, Nippon Seiki, etc.) ), A type that causes high-speed collision in a slit-shaped flow path (“Microfluidizer” manufactured by Microfluidics), and a type that causes high-speed collision in a single-character flow path that is connected in phase by 90 ° ( "Nanomizer" manufactured by Yoshida Kikai Kogyo Co., Ltd.), a type that generates multiple collisions between liquids and fluids within the same nozzle ("Nanomaker" manufactured by SGS Engineering Co., Ltd.), and fluids in a flat channel element Collision type ("Aqua" manufactured by Aquatech) or jetting from an opposing orifice into an aspheric structure room And the like type (produced by "ULTIMIZER" Sugino Machine Co., Ltd.).

  These liquid collision dispersive devices under high pressure have some differences in the dispersion effect depending on the type of fluorine-containing resin fine particles due to the characteristics of the device type. Compared to the case of using a dispersing apparatus, the atomization progresses with a remarkably high efficiency, and a dispersion having a uniform particle size distribution can be obtained.

  The dispersion that has passed through the liquid collision dispersion process under high pressure according to the present invention then enters the filtration process, and causes the clogging of the liquid collision dispersion equipment under high pressure by circulating the dispersion process and the filtration process. Aggregated particles of the fluorine-containing resin fine particles can be removed, and a dispersion liquid having a uniform particle size distribution can be obtained.

  In the filtration process, a filter is installed to remove the overdispersed agglomerates generated in the liquid collision dispersion equipment under high pressure, and the dispersion liquid that has passed through the filtration process is circulated again to the disperser, and the orifice of the liquid collision dispersion equipment under high pressure. The dispersion liquid is circulated and dispersed a plurality of times while preventing the mixing of the particles blocking the flow path.

  A preferable discharge pressure at the time of the liquid collision is 50 MPa to 150 MPa. And the filter used by the filtration process connected after that has a preferable mesh filter of 20-100 micrometers.

  As described above, a fluororesin fine particle dispersion having an average primary particle size of less than 0.2 μm is prepared by circulating the liquid collision dispersion step and the filtration step under high pressure a plurality of times to produce a fluororesin fine particle dispersion. An organic photoreceptor that can be obtained and can prevent clogging during dispersion, and as a result, a uniform surface layer can be formed using a coating solution prepared from the dispersion, and a good electrophotographic image can be obtained. Can be produced.

  Here, as the above-mentioned multiple times circulation, the liquid collision dispersion step and the filtration step may be carried out a plurality of times (preferred number of circulation: circulation of 5 to 100 times). The process may be completed, and the batch of the liquid collision dispersion process and the filtration process for each time may be repeated. The number of circulations in the latter batch method is preferably 2-30.

  FIG. 7 illustrates an example of a dispersion processing apparatus that circulates the liquid collision dispersion step and the filtration step under high pressure.

  In FIG. 7, the material to be dispersed charged from the non-dispersed material charging container 1 is sent to the dispersion step A. That is, the pipe is filled during the suction-discharge process of the high-pressure pump 2. As the high-pressure pump, a hydraulic pump or a plunger pump is used. The material to be dispersed is pumped to the liquid collision jig 4 in the pump compression process and moved in a high pressure state by moving in the jig having one to several orifices 7 (diameter 50 μm to 2 mm, length 2 to 10 mm). Liquid collision occurs. Thereafter, the material to be dispersed is sent to the filtration step B, filtered by the filtration filter 9, and then subjected to circulation and dispersion a plurality of times, and then sent to the sample receiving container 5. In the figure, 3 is a high-pressure pipe, 6 is a pressure gauge, and 8 is a three-way valve.

  The fluorine-containing resin fine particles according to the present invention are a homopolymer or copolymer of a fluorine-containing polymerizable monomer, or a copolymer of a fluorine-containing polymerizable monomer and a fluorine-free polymerizable monomer. The fluorine-containing polymerizable monomer has a general formula;

(In the formula, at least one group of R ^{4 to} R ⁷ is a fluorine atom, and the remaining groups are each independently a hydrogen atom, a chlorine atom, a methyl group, a monofluoromethyl group, a difluoromethyl group, or trifluoro). Is a methyl group). Preferable fluorine-containing polymerizable monomers include ethylene tetrafluoride, ethylene trifluoride, ethylene trifluoride chloride, propylene hexafluoride, vinyl fluoride, vinylidene fluoride, ethylene difluoride dichloride and the like. Two or more types of monomers may be used as the fluorine-containing polymerizable monomer.

  Examples of the fluorine-free polymerizable monomer include vinyl chloride. Two or more types of monomers may be used as the fluorine-free polymerizable monomer.

  All of the fluororesin fine particles are preferably made of a homopolymer or copolymer of a fluoropolymerizable monomer among the above-mentioned constituent materials, more preferably polytetrafluoroethylene (PTFE) or polytrifluoride. Ethylene, ethylene tetrafluoride-hexafluoropropylene copolymer, polyvinylidene fluoride, especially polytetrafluoroethylene.

  The average molecular weight of the polymer constituting the fluorine-containing resin fine particles is not particularly limited as long as the object of the present invention can be achieved, but usually the range of 10,000 to 1,000,000 is preferable.

  As the binder resin in the surface layer, it is preferable to use a resin having a surface active group that assists the dispersibility of the fluororesin fine particles in the partial structure of the resin. For example, a polycarbonate or polyarylate having a siloxane group in the partial structure A fluorinated graft acrylic resin or the like is preferable. The molecular weight of these resins is preferably 10,000 to 100,000.

  Further, when the surface layer is formed using the fluorine-containing resin fine particles of the present invention, it is preferable to increase the ratio of the fluorine-containing resin fine particles in the surface layer, and at least 3 masses with respect to 100 parts by mass of the binder resin. It is preferably used in an amount of not less than 100 parts and not more than 100 parts by mass. If the amount is less than 3 parts by mass, it is difficult to form a surface layer satisfying a contact angle of 90 ° or more. If the amount is more than 100 parts by mass, the surface layer becomes a fragile film, and scratches or the like are likely to occur.

  Further, the dispersion of the fluororesin fine particles according to the present invention is a low-boiling solvent having good dispersibility, preferably an organic solvent having a boiling point of 120 ° C. or lower under atmospheric pressure (for example, THF, ethanol, toluene, dichloroethane, etc. ) Is preferably used. By using such a low-boiling solvent, a stable dispersion can be produced while suppressing the cohesiveness between the fluororesin fine particles. At the same time, the dispersion liquid is adjusted and used as a coating liquid (the dispersion liquid may become the coating liquid as it is), and a quantity-regulating coating device (a coating device that controls the coating amount to control the film thickness of the surface layer) The surface layer is formed and dried to make the film thickness of the surface layer constant, prevent aggregation of the fluororesin fine particles, and form a surface layer having a uniform low surface energy.

  Examples of the amount-regulating coating device include a coating device using a circular slide hopper type coating head or an extrusion type coating head. Among these, a coating apparatus having a circular slide hopper type coating head described later (hereinafter also referred to as a circular slide hopper type coating apparatus) is preferably used. A coating apparatus having such a circular coating head has a larger number of cylindrical conductive supports (excluding a part of the upper end) immersed in a coating solution than a dip coating in which coating is performed. Since the surface layer is formed in one way without retaining the dispersion liquid, the dispersed particles of the fluororesin fine particles do not repeatedly receive an agglomeration share in the dispersion, and the fluororesin fine particles settle in the coating liquid. It is possible to form a uniform surface layer by preventing (the fluororesin fine particles have a high specific gravity and tend to settle as compared with the dispersion medium). Moreover, since a dispersion can be prepared every time the photoreceptor is manufactured, aggregation and sedimentation of the dispersion over time can be prevented, and the lower layer already formed on the cylindrical conductive support can be dissolved at the time of surface layer formation. Since it can be applied, the surface layer having uniform dispersibility can be formed with little aggregation of the fluororesin fine particles even during coating and drying. In the bead formation coating, the coating film thickness can be accurately controlled by the flow rate of the coating liquid discharged from the coating apparatus, and the optically uniform surface layer can be formed with little variation in the film thickness. As a result, an electrophotographic image with good sharpness can be formed.

  Hereinafter, a coating apparatus having a circular slide hopper type coating head preferably used in the present invention will be described.

  FIG. 1 is a perspective view showing the entire configuration of a coating apparatus (continuous coating apparatus) having a circular slide hopper type coating head, which is an embodiment of a coating apparatus having a circular coating head according to the present invention. In FIG. 1, 10t is a supply means for supplying the cylindrical support 1t to a predetermined position vertically below the circular coating means 40t and pushing it upward, and 20t is a cylinder that grips the outer peripheral surface of the supplied cylindrical support 1t. Conveying means for vertically pushing up from the bottom of the stack with the shaft aligned, 30t is positioning means for aligning the cylindrical support 1t with the center of the annular application part of the coating apparatus, and 40t is the position of the cylindrical support Circular coating means for continuously coating the coating liquid on the outer peripheral surface, 50t is a drying means for drying the coating liquid coated on the cylindrical support 1t, and 60t is a plurality of stacked layers that have been dried and transported vertically. Separating and discharging means for separating the cylindrical supports from each other and discharging them one by one.

  This continuous coating apparatus has a configuration in which each of the above-described means is continuously arranged on the vertical center line ZZ, and fully automated production that does not require manual operation is achieved with high accuracy. That is, the supply means 10t has a plurality of attachment means 11t for mounting the cylindrical support 1t, and the movable table 12t rotates the movable table 12t and feeds it to a vertical line connected to the transport means 20t. The driving means 13t, the lifting / lowering means 14t for pushing up the cylindrical support 1t already gripped and conveyed upward by the conveying means 20t, and a cylindrical support for supplying the cylindrical support provided at the upper end of the lifting / lowering means 14t. It comprises control means (not shown) for controlling the timing of rotation by the hand means 15t and the drive means 13t and the push-up timing by the elevating means 14t. The cylindrical support 1t is supplied onto the movable table 12t by a robot handle.

  The conveying means 20t provided above the supply means 10t has two sets of gripping means 21t and 22t that can be pressed against and separated from the outer peripheral surface of the cylindrical support 1t and can be moved vertically and vertically. It has a function of positioning, gripping and transporting the support 1t upward.

  2 is a sectional view showing the positioning means 30t and the vertical circular application means 40t, and FIG. 3 is a perspective view of the vertical circular application means 40t. In addition, the circular application means 40t of this figure is a circular slide hopper type application device.

  As shown in FIG. 2, a plurality of cylindrical supports 1tA, 1tB, 1tC, and 1tD (hereinafter also referred to as cylindrical supports 1t) that are vertically stacked along the center line ZZ are continuously provided. The circular coating means 40t is coated on the outer peripheral surface of the cylindrical support 1t (a photosensitive layer may already be formed on the cylindrical support 1t). The coating liquid L is coated in a cylindrical shape by a coating head (hopper coating surface) 41t which is a directly related part. The cylindrical support 1t may be a hollow drum, for example, an aluminum drum, a plastic drum, or a seamless belt type support. In the coating head 41t, a narrow coating liquid distribution slit (slit) 43t having a coating liquid outlet 42t that opens toward the cylindrical support 1t is formed in the horizontal direction. The slit 43t communicates with an annular coating liquid distribution chamber (coating liquid reservoir chamber) 44t, and the coating liquid L in the storage tank 2t is supplied to the annular coating liquid distribution chamber 44t via a supply pipe 4 by a pressure pump 3t. It comes to supply. On the other hand, below the coating solution outlet 42t of the slit 43t, the coating solution slide is formed so as to continuously incline and terminate in a dimension slightly larger than the outer diameter of the cylindrical support 1t. A surface (hereinafter referred to as a slide surface) 45t is formed. In the application by the circular application means 40t, when the coating liquid L is pushed out from the slit 43t in the process of pulling up the cylindrical support 1t and flows down along the slide surface 45t, the application liquid reaching the end of the slide surface 45t is obtained. A bead (a pool of coating solution) is formed between the end of the slide surface 45t and the outer peripheral surface of the photosensitive layer of the cylindrical support 1t, and then applied to the photosensitive layer surface of the cylindrical support 1t. Since the end of the slide surface 45t and the cylindrical support 1t are arranged with a certain gap, the layer already applied is damaged even when the layers having different properties are formed without damaging the surface of the photosensitive layer. It can apply without doing.

  On the other hand, an air vent member 46t for removing bubbles in the coating liquid distribution chamber 44t is provided in a part of the coating liquid distribution chamber 44t at a position farthest from the coating liquid supply portion of the pressure feed pump 3t. When the coating liquid L in the storage tank 2t is supplied to the coating liquid distribution chamber 44t and supplied from the coating liquid distribution slit 43t to the coating liquid outlet 42t, the on-off valve 47t is opened and the coating liquid distribution chamber 44t is opened from the air vent member 46t. The air inside is exhausted.

  A positioning means 30t for positioning the circumferential direction of the cylindrical support 1t is fixed to the lower part of the circular application means 40t. The main body 31t of the positioning device 30t for the cylindrical support 1t is provided with a plurality of air supply ports 32t and a plurality of exhaust ports 33t. The plurality of air supply ports 32t are connected to an air supply pump (not shown), and a gas such as air is pumped. A discharge port 34t passes through one end of the air supply port 32t on the side of the cylindrical support 1t facing the outer peripheral surface of the photosensitive layer. The discharge port 34t faces the outer peripheral surface of the photosensitive layer of the cylindrical support 1t with a predetermined gap. The gap is 20 μm to 3 mm, preferably 30 μm to 2 mm. If the gap is smaller than 20 μm, the slight fluctuation of the cylindrical support 1t may contact the inner wall of the main body 31t and easily damage the photosensitive layer surface. If this gap is larger than 3 mm, the positioning accuracy of the cylindrical support 1t is lowered. The discharge port 34t is a small-diameter nozzle having a diameter of 0.01 to 1.0 mm, preferably 0.05 to 0.5 mm.

  The inner peripheral surface of the lower part of the inner wall of the main body 31t is a tapered surface 35t having an enlarged entrance side. The tapered surface 35t is, for example, a conical surface having an axial length of 50 mm and a one-side inclination angle of 0.5 mm. By providing the tapered surface 35t, when the cylindrical support 1t enters the inner wall of the main body 31t, the tip of the cylindrical support 1t is prevented from coming into contact with the inner peripheral surface of the inner wall.

  The gas pumped from the air supply pump is introduced into the main body 31t from the plurality of air supply ports 32t and discharged from the plurality of discharge ports 34t, and is uniform with the outer peripheral surface of the cylindrical support 1t ( Gas) film layer is formed. The discharged gas is discharged out of the apparatus through a plurality of exhaust ports 33t.

  The discharge port 34t has an opening diameter of 0.01 to 1 mm, preferably 0.05 to 0.5 mm, for example, 0.2 to 0.5 mm. The opening diameter of the exhaust port 33t is 1.0 to 10 mm, preferably 2.0 to 8.0 mm, for example, 3 to 5 mm.

  The gas supplied to the air supply port 23t is preferably air or an inert gas such as nitrogen gas. The gas is preferably a clean gas of class 100 or higher according to JIS standards.

  Above the circular coating means 40t, a drying means 50t comprising a drying hood 51t and a dryer 53t is provided.

  FIG. 4 is a cross-sectional view as seen from the top of the circular application means 40t.

  In FIG. 4, the coating liquid L is supplied to the coating liquid distribution chamber 44t through the supply pipe 4t. The coating liquid distribution chamber 44t is preferably provided with stirring means 48t. At the position where the coating liquid L branched right and left from the supply pipe 4t joins again, turbulent flow of the coating liquid L is likely to occur and coating streaks are likely to occur, so these positions (in the case of FIG. 4, the supply pipe 44t). Application streaks can be prevented by providing a stirring means 48t or rotating and stirring the entire 44t. The coating liquid L flows out from the coating liquid distribution chamber 44t through the coating liquid outlet 42t of the slit 43t and flows down to the slide surface 45t. Thereafter, a bead is formed between the end of the slide surface and the cylindrical support 1, and the coating layer 5 t is formed on the cylindrical support 1.

  FIG. 5 is a cross-sectional view of the circular application means 40t and the solvent vapor reservoir hood 51t and the drying hood 52t provided on the circular application means 40t in FIG. The solvent vapor reservoir hood 51t has an annular wall surface, and is filled with solvent vapor evaporated from the coating film. The solvent vapor concentration of the solvent vapor reservoir hood is preferably 70% by volume or more of the total gas volume near the outlet (near the boundary with the dry hood 52t). Further, the length of the solvent vapor reservoir hood is preferably adjusted so that the residence time of the cylindrical support is 3 to 25 seconds. The dry hood 52t has an annular wall surface, and a plurality of openings 52tA are formed in the dry wall surface, and the solvent is discharged to the outside from the openings.

  The cylindrical support 1t is raised in the direction of the arrow, and the coating liquid L is applied by the hopper coating surface (coating head) 41t of the circular coating means 40t to form a coating layer 5t. The coating layer 5t formed on the photosensitive layer of the cylindrical support 1t is gradually dried while passing through the solvent vapor reservoir hood 51t and the drying hood 52t to prevent aggregation of the fluororesin fine particles in the surface layer, Moreover, it acts to average out the distribution of the fluororesin fine particles in the surface layer.

  FIG. 6 is a partially broken perspective view of the positioning means 30t. FIG. 6 shows an example of the positioning means 30t shown in FIG. The positioning means 30t has a length H = 200 mm, H1 to H4 = 50 mm each, a discharge port (34t) diameter of 0.3 mm, and a discharge port (36t) diameter of 1.0 mm alternately with discharge devices 37t and exhaust devices 38t. It has a stacked configuration and can be used by stacking as many stages as necessary.

  The coating apparatus using the circular slide hopper type coating head (also called a circular slide hopper type coating apparatus) causes the coating liquid L to flow down along the slide surface 45t, and the coating liquid reaching the end of the slide surface 45t A bead is formed between the terminal end of the slide surface 45t and the outer peripheral surface of the photosensitive layer of the cylindrical support 1t, and then applied to the surface of the photosensitive layer of the cylindrical support 1t. Since the coating device is arranged with a gap between the end of the slide surface and the cylindrical support, the coating device has already been applied without damaging the cylindrical support and even when forming layers having different properties. Can be applied without damaging the layer. Furthermore, when multiple layers with different properties and dissolved in the same solvent are formed, the lower layer components are hardly eluted to the upper layer side because the time in the solvent is much shorter than the dip coating method. Since it can apply | coat without eluting to a tank, it can apply | coat, without deteriorating the dispersibility of a fluorine-containing resin microparticle. Moreover, the coating liquid containing the fluorine-containing resin particles according to the present invention can form a good surface layer even if a spray type coating apparatus is used in addition to the circular slide hopper type coating apparatus.

  The fluorine-containing resin fine particles according to the present invention are preferably fluorine-containing resin fine particles having an average primary particle size of 0.02 μm or more and less than 0.20 μm. When the average primary particle size is less than 0.02 μm, the stability of the dispersion is deteriorated, the fluororesin fine particles are agglomerated, it is difficult to uniformly disperse, and the local variation of the contact angle tends to increase. , White spots and poor cleaning are likely to occur. On the other hand, if the average primary particle size is larger than 0.20 μm, agglomerated particles are likely to be formed due to sedimentation, and the contact angle of the surface tends to decrease.

  The average primary particle diameter (D1) of the fluororesin fine particles is enlarged 2000 times by observation with a transmission electron microscope, and 100 primary particles are taken out randomly (in order to make primary particles, the fluororesin fine particles are dispersed in a dispersion medium). And may be observed after the aggregated particles are crushed) and is a measured value as an average diameter in the ferret direction by image analysis. The ferret diameter (Feret) is defined as a constant tangential diameter defined by the distance between two parallel lines that sandwich the particle.

  The present invention is an organic photoreceptor having a surface layer as described above. The constitution of the organic photoreceptor other than the surface layer will be described below.

  In the present invention, the organic photoconductor means an electrophotographic photoconductor constituted by providing an organic compound with at least one of a charge generation function and a charge transport function essential to the configuration of the electrophotographic photoconductor. All known organic photoconductors such as a photoconductor composed of an organic charge generating material or an organic charge transport material, a photoconductor composed of a polymer complex with a charge generating function and a charge transport function are contained.

The organophotoreceptor of the present invention comprises a step of dispersing a fluororesin fine particle by liquid collision under high pressure and a filtration step in an organophotoreceptor having a surface layer containing at least a fluororesin fine particle on a conductive support. As long as it is prepared using a coating liquid produced by using a dispersion obtained by circulating the liquid (components other than fluororesin fine particles may be mixed in the dispersion and the dispersion may be used as it is as a coating liquid) For example, the following configurations may be mentioned;
1) A structure in which a charge generation layer and a charge transport layer are sequentially laminated as a photosensitive layer on a cylindrical conductive support;
2) A structure in which a charge generation layer, a first charge transport layer, and a second charge transport layer are sequentially laminated as a photosensitive layer on a cylindrical conductive support;
3) A structure in which a single layer containing a charge transport material and a charge generation material is formed as a photosensitive layer on a cylindrical conductive support;
4) A structure in which a charge transport layer and a charge generation layer are sequentially laminated as a photosensitive layer on a cylindrical conductive support;
5) A structure in which a surface protective layer is further formed on the photosensitive layer of the photoreceptors 1) to 5) above.

  The photoconductor may have any of the above configurations. The surface layer of the photoconductor is a layer in which the photoconductor is in contact with the air interface. When only a single-layer type photoconductive layer is formed on the cylindrical conductive support, the photoconductive layer is the surface layer. In the case where a single-layer or laminated photosensitive layer and a surface protective layer are laminated on a cylindrical conductive support, the surface protective layer is the outermost surface layer. In the present invention, the configuration 2) is most preferably used. Note that, regardless of the configuration of the photoreceptor of the present invention, an undercoat layer may be formed on the cylindrical conductive support prior to the formation of the photosensitive layer.

  The charge transport layer of the present invention means a layer having a function of transporting charge carriers generated in the charge generation layer by light exposure to the surface of the organic photoreceptor, and the specific detection of the charge transport function is charge generation. This can be confirmed by laminating a layer and a charge transport layer on a cylindrical conductive support and detecting the photoconductivity.

  A specific configuration of the photoreceptor will be described below by taking as an example the layer configuration of 2) which is most preferably used in the present invention.

Cylindrical conductive support The cylindrical conductive support of the present invention means a cylindrical support necessary to be able to form an endless image by rotating, and the cylindricity is preferably 5 to 40 μm, preferably 7 to 30 μm is more preferable.

  This cylindricity is based on JIS standard (B0621-1984). That is, when the cylindrical substrate is sandwiched between two coaxial geometric cylinders, it is represented by the difference in radius at the position where the distance between the two coaxial cylinders is minimum. In the present invention, the difference in radius is represented by μm. The method of measuring the cylindricity is obtained by measuring the roundness of 7 points in total, that is, 2 points 10 mm on both ends of the cylindrical support, 4 points on the center, and 4 points obtained by dividing the distance between the ends. The measuring device can be measured using a non-contact universal roll diameter measuring machine (manufactured by Mitutoyo Corporation).

As the material for the cylindrical conductive support, a metal drum such as aluminum or nickel, a plastic drum deposited with aluminum, tin oxide, indium oxide, or the like, or a paper / plastic drum coated with a conductive substance can be used. . The cylindrical conductive support preferably has a specific resistance of 10 ³ Ωcm or less at room temperature.

  The cylindrical conductive support used in the present invention may be one having a sealed anodized film formed on the surface thereof. The alumite treatment is usually performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid, etc., but anodizing treatment in sulfuric acid gives the most preferable result. In the case of anodizing in sulfuric acid, the sulfuric acid concentration is preferably 100 to 200 g / l, the aluminum ion concentration is 1 to 10 g / l, the liquid temperature is about 20 ° C., and the applied voltage is preferably about 20 V. It is not limited. The average film thickness of the anodized film is usually 20 μm or less, particularly preferably 10 μm or less.

Intermediate layer In the present invention, an intermediate layer having a barrier function may be provided between the cylindrical conductive support and the photosensitive layer.

  In the present invention, in order to improve the adhesion between the cylindrical conductive support and the photosensitive layer, or to prevent charge injection from the support, an intermediate layer (undercoat) is provided between the support and the photosensitive layer. Including layers). Examples of the material for the intermediate layer include polyamide resins, vinyl chloride resins, vinyl acetate resins, and copolymer resins containing two or more of these resin repeating units. Of these subbing resins, a polyamide resin is preferable as a resin capable of reducing the increase in residual potential due to repeated use. The film thickness of the intermediate layer using these resins is preferably 0.01 to 0.5 μm.

  Examples of the intermediate layer preferably used in the present invention include an intermediate layer using a curable metal resin obtained by thermosetting an organic metal compound such as a silane coupling agent or a titanium coupling agent. As for the film thickness of the intermediate | middle layer using curable metal resin, 0.1-2 micrometers is preferable.

  An intermediate layer preferably used in the present invention includes an intermediate layer in which inorganic particles are dispersed in a binder resin. The average particle diameter of the inorganic particles is preferably 0.01 to 1 μm. In particular, an intermediate layer in which N-type semiconductive fine particles subjected to surface treatment are dispersed in a binder is preferable. For example, an intermediate layer in which titanium oxide having an average particle size of 0.01 to 1 μm, which has been surface-treated with silica / alumina treatment and a silane compound, is dispersed in a polyamide resin. The film thickness of such an intermediate layer is preferably 1 to 20 μm.

  The N-type semiconducting fine particles are fine particles having the property of using conductive carriers as electrons. That is, the property that the conductive carrier is an electron is that the N-type semiconducting fine particles are contained in an insulating binder to effectively block hole injection from the substrate, and to convert electrons from the photosensitive layer into electrons. On the other hand, it has the property which does not show blocking property.

  Here, a method for discriminating N-type semiconductor particles will be described.

  An intermediate layer having a film thickness of 5 μm is formed on the cylindrical conductive support (an intermediate layer is formed using a dispersion in which 50% by mass of particles are dispersed in a binder resin constituting the intermediate layer). The intermediate layer is negatively charged and the light attenuation characteristics are evaluated. In addition, the light attenuation characteristics are similarly evaluated by charging to positive polarity.

  N-type semiconductive particles are particles that are dispersed in the intermediate layer in the above evaluation when the light attenuation when charged negatively is greater than the light attenuation when charged positively. It is called semiconductive particle.

Specific examples of the N-type semiconducting fine particles include fine particles of titanium oxide (TiO ₂ ), zinc oxide (ZnO), tin oxide (SnO ₂ ), etc. In the present invention, titanium oxide is particularly preferably used. It is done.

  The average particle diameter of the N-type semiconducting fine particles used in the present invention is preferably in the range of 10 nm to 500 nm in the number average primary particle diameter, more preferably 10 nm to 200 nm, and particularly preferably 15 nm to 50 nm. .

  The intermediate layer using N-type semiconducting fine particles whose number average primary particle size is within the above range can be finely dispersed in the layer, has sufficient potential stability, and generates black spots. Has a prevention function.

  For example, in the case of titanium oxide, the number-average primary particle size of the N-type semiconducting fine particles is magnified 10,000 times by observation with a transmission electron microscope, and 100 particles are randomly observed as primary particles. It is measured as the number average diameter.

  The shape of the N-type semiconducting fine particles used in the present invention includes dendritic, needle-like, and granular shapes. For example, in the case of titanium oxide particles, the N-type semiconductive fine particles have a crystalline form. There are anatase type, rutile type and amorphous type, but any crystal type may be used, or two or more crystal types may be mixed and used. Of these, the rutile type is the best.

  One of the hydrophobizing surface treatments performed on the N-type semiconducting fine particles is a plurality of surface treatments, and the last surface treatment is a surface treatment with a reactive organosilicon compound. Is to do. In addition, at least one of the surface treatments is at least one surface treatment selected from alumina, silica, and zirconia, and finally the surface treatment of the reactive organosilicon compound is performed. It is preferable.

  Alumina treatment, silica treatment, and zirconia treatment are treatments for depositing alumina, silica, or zirconia on the surface of the N-type semiconducting fine particles. Alumina, silica, and zirconia deposited on these surfaces include alumina, silica, Zirconia hydrates are also included. The surface treatment of the reactive organosilicon compound means using a reactive organosilicon compound in the treatment liquid.

  In this way, the surface treatment of the N-type semiconductive fine particles such as titanium oxide particles was performed at least twice, so that the surface of the N-type semiconductive fine particles was uniformly coated (treated), and the surface treatment was performed. When N-type semiconducting fine particles are used in the intermediate layer, a good photoconductor having good dispersibility of N-type semiconductive fine particles such as titanium oxide particles in the intermediate layer and causing no image defects such as black spots. You can get it.

Photosensitive layer Charge generation layer In the organic photoreceptor of the present invention, the above-mentioned titanyl phthalocyanine adduct pigment is used as a charge generation material, but other phthalocyanine pigments, azo pigments, perylene pigments, azurenium pigments, etc. are used in combination. Can do.

  When a binder is used as the CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, phenoxy resin, and the like. Can be mentioned. The ratio of the binder resin to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The thickness of the charge generation layer is preferably 0.3 μm to 2 μm.

Charge Transport Layer As described above, in the present invention, the charge transport layer is preferably composed of a plurality of charge transport layers, and the uppermost charge transport layer contains fluorine-based resin particles.

  The charge transport layer contains a charge transport material (CTM) and a binder resin that disperses and forms a CTM. As other substances, additives such as an antioxidant may be contained in addition to the above-described fluororesin particles as necessary.

  As the charge transport material (CTM), a known hole transport property (P-type) charge transport material (CTM) is preferably used. For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer.

  The binder resin used for the charge transport layer (CTL) may be either a thermoplastic resin or a thermosetting resin. For example, polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and these resins A copolymer resin containing two or more of the repeating unit structures. In addition to these insulating resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used. Of these, polycarbonate resins are most preferred because of their low water absorption and good CTM dispersibility and electrophotographic characteristics.

  The ratio of the binder resin to the charge transport material is preferably 50 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  The surface layer containing the fluororesin fine particles of the present invention preferably contains an antioxidant. The surface layer containing the fluorine-containing resin fine particles is easily oxidized by an active gas such as NOx or ozone during charging of the photoconductor, and image blurring is likely to occur. However, the presence of an antioxidant causes image blurring. Can be prevented. Typical examples of the antioxidants are those that prevent the action of oxygen under conditions of light, heat, discharge, etc. on auto-oxidizing substances present in the organic photoreceptor or on the surface of the organic photoreceptor, It is a substance that has the property of inhibiting.

  Solvents or dispersion media used to form layers such as intermediate layers, charge generation layers, and charge transport layers include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone , Methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, Tetrachloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cello Lube, and the like. Although this invention is not limited to these, Dichloromethane, 1, 2- dichloroethane, methyl ethyl ketone, etc. are used preferably. These solvents may be used alone or as a mixed solvent of two or more.

  Next, an image forming apparatus using the organic photoreceptor of the present invention will be described.

  FIG. 8 is a schematic cross-sectional view of a cleanerless image forming apparatus 1 using the organic photoreceptor according to the present invention. The image forming apparatus 1 includes a photosensitive cartridge 2, a developing cartridge 3, an exposure device 4 that emits a laser beam modulated based on an image signal from the outside while deflecting, a paper feeding device 5 that supplies recording paper, A transfer roller 6, a fixing device 7 and a paper discharge tray 8 are provided.

  The photoconductor cartridge 2 includes a photoconductor 21 formed by forming a thin film layer of an organic photoconductive material on the outer peripheral surface of a cylindrical body, a charging brush 22 and the like. The developing cartridge 3 includes a developing sleeve (not shown), a stirring roller, and a toner tank in which toner and a carrier are accommodated. A developing bias is applied to the developing sleeve from a developing power source (not shown). Both cartridges are closed when inserted into the image forming apparatus 1 in order to prevent problems caused by mechanical contact when the cartridge is attached to or detached from the image forming apparatus 1, and are removed from the image forming apparatus 1. A protective cover (not shown) that is sometimes opened is provided.

  Since the image forming process is well known, only a brief description will be given below. First, the surface of the photoreceptor 21 is uniformly charged with a predetermined voltage by the charging brush 22. The exposure device 4 generates a modulated laser beam (indicated by a broken arrow in the figure), deflects the laser beam by a polygon mirror (not shown), deflects and scans the surface of the photosensitive member 21, and applies it to the charged surface. The electrostatic latent images corresponding to the image information are sequentially formed. The toner in the toner tank is stirred by a stirring roller and then supplied onto the developing sleeve to form a toner image corresponding to the electrostatic latent image at a portion facing the photoreceptor 21. At the same time, residual toner existing in a portion (non-image portion) that has not been exposed on the surface of the photoconductor 21 is developed using the potential difference between the developing bias voltage applied to the developing sleeve and the surface potential of the photoconductor 21. The cartridge is recovered by electrostatic force. On the other hand, the toner image is electrostatically transferred onto the recording paper by the transfer roller 6 disposed facing the photoconductor 21. Note that the recording paper is conveyed from the paper feeding device 5 along a conveyance path indicated by a solid line arrow in the drawing. Next, the recording paper is conveyed to the fixing device 7 where the unfixed toner image is heat-fixed on the recording paper. Finally, the recording paper on which a desired image is formed is discharged from the paper discharge tray 8. By repeating the above-described series of processes, a large amount of original can be duplicated at high speed.

  The charging brush mechanically agitates the residual toner sent to the contact portion with the photoconductor by the rotation of the photoconductor and diffuses it on the surface of the photoconductor until it becomes unreadable. The charging brush electrostatically adsorbs and collects residual toner having the opposite polarity (reverse polarity) to the charging polarity of the photoconductor, and charges it to the same polarity (regular polarity) as the charging polarity of the photoconductor. Discharge onto the surface of the photoreceptor.

  FIG. 9 is a schematic cross-sectional view of the photoreceptor cartridge 2 that is detachable from the image forming apparatus 1. The photosensitive member cartridge 2 includes a protective member 28 with a protective cover, a photosensitive member 21 as an image carrier, a charging brush 22 disposed around the photosensitive member 21, and a power source for applying a predetermined voltage to the charging brush 22. The connecting member 23, the pre-charge film 24, the charge leveling members (sponge-like charging members) 25 and 26, and the power source connecting member 27 are accommodated.

  The photosensitive member 21 is rotated in the direction of the arrow in the drawing by a driving device (not shown). The charging brush 22 is obtained by implanting conductive yarn made of hairy fibers on a brush support. The charging brush 22 is in contact with the surface of the photosensitive member 21 and is rotated in the same direction as the rotational direction of the photosensitive member 21 in the direction of the arrow in the drawing, that is, in the contact portion with the photosensitive member 21 by a driving device (not shown). . At the time of image formation, a voltage is applied to the charging brush 22 from a charging power source (not shown), whereby the surface of the photoreceptor 21 is uniformly charged to a predetermined polarity. On the other hand, at the time of non-image formation, a voltage having a polarity opposite to that at the time of image formation is applied to the charging brush 22 from the charging power source. The charging polarity of the toner is the same as the polarity of the charging voltage at the time of image formation. Therefore, at the time of non-image formation, the toner accumulated in the charging brush 22 can be ejected onto the photoreceptor 21 by electrostatic repulsion.

  The development pre-charge film 24 and the charge leveling members 25 and 26 are disposed for the purpose of compensating uneven charging due to the charging brush 22.

  A charging roller may be used instead of the charging brush shown in FIGS.

  FIG. 10 is a cross-sectional configuration diagram of a cleaner-less color image forming apparatus using the organic photoreceptor of the present invention.

  This color image forming apparatus is called a tandem type color image forming apparatus, and includes a plurality of sets of image forming units (image forming units) 10Y, 10M, 10C, 10Bk, an endless belt-shaped intermediate transfer body unit 7, and a feeding unit. It comprises a paper conveying means 21 and a fixing means 24. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  An image forming unit 10Y that forms a yellow image includes a charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, and a primary transfer unit disposed around a drum-shaped photoconductor 1Y as a first image carrier. It has a primary transfer roller 5Y, a static eliminator 6Y that neutralizes the surface of the photoreceptor, and a toner equalizing brush 7Y that equalizes the toner distribution. An image forming unit 10M that forms a magenta image includes a drum-shaped photosensitive member 1M as a first image carrier, a charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roller 5M as a primary transfer unit, A static eliminator 6M that neutralizes the surface of the photoreceptor and a toner uniformizing brush 7M that uniformizes the toner distribution are provided. An image forming unit 10C for forming a cyan image includes a drum-shaped photoreceptor 1C as a first image carrier, a charging unit 2C, an exposure unit 3C, a developing unit 4C, and a primary transfer roller 5C as a primary transfer unit. A static eliminator 6C for neutralizing the surface of the photoreceptor and a toner uniformizing brush 7C for uniformizing the toner distribution are provided. The image forming unit 10Bk that forms a black image includes a drum-shaped photoreceptor 1Bk as a first image carrier, a charging unit 2Bk, an exposure unit 3Bk, a developing unit 4Bk, a primary transfer roller 5Bk as a primary transfer unit, and a photoreceptor. A neutralizer 6Bk for neutralizing the surface and a toner equalizing brush 7Bk for equalizing the toner distribution are provided.

  The developing means 4Y, 4M, 4C, and 4Bk have developing rollers 4Yr, 4Mr, 4Cr, and 4Bkr that develop the electrostatic latent image on the photoconductor. A developing bias potential (Vbs) positioned between the exposed portion potential (Vw) and the exposed portion potential (Vb) is loaded, and reversal development is performed. By appropriately setting the developing bias potential, fog (including black spots) that easily occurs during reversal development is prevented, and the toner adhering to the unexposed portion of the photoreceptor is attracted to the developing roller and collected. be able to. The development bias potential is preferably set to a value 50 to 400 V lower than the unexposed portion potential (Vw) at the development position, more preferably 100 to 350 V.

  The endless belt-like intermediate transfer body unit 7 includes an endless belt-like intermediate transfer body 70 as a second image carrier having a semiconductive endless belt shape that is wound around a plurality of rollers and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10Bk is sequentially transferred onto a rotating endless belt-shaped intermediate transfer body 70 by primary transfer rollers 5Y, 5M, 5C, and 5Bk as primary transfer means. Thus, a synthesized color image is formed. A sheet P as a recording material (a support for carrying a fixed final image: for example, plain paper, transparent sheet, etc.) housed in the sheet feeding cassette 20 is fed by a sheet feeding means 21 and has a plurality of intermediate rollers. After passing through 22A, 22B, 22C, 22D and the registration roller 23, it is conveyed to the secondary transfer roller 5A as the secondary transfer means, and is secondarily transferred onto the paper P, and the color images are collectively transferred. The paper P on which the color image has been transferred is fixed by the fixing unit 24, is sandwiched between the paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus.

  On the other hand, after the color image is transferred onto the sheet P by the secondary transfer roller 5A as the secondary transfer unit, the residual toner is removed by the cleaning unit 6A from the endless belt-shaped intermediate transfer body 70 from which the sheet P is separated by curvature.

  During the image forming process, the primary transfer roller 5Bk is always in pressure contact with the photoreceptor 1Bk. The other primary transfer rollers 5Y, 5M, and 5C are in pressure contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5A comes into pressure contact with the endless belt-shaped intermediate transfer body 70 only when the sheet P passes through the secondary transfer roller 5A and secondary transfer is performed.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10Bk and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10Bk are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1Bk in the drawing. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 73, 74, primary transfer rollers 5Y, 5M, 5C, 5Bk, and cleaning means 6A. Consists of.

  The organophotoreceptor of the present invention is generally applicable to electrophotographic apparatuses such as electrophotographic copying machines, laser printers, LED printers, and liquid crystal shutter printers, but further displays, recordings, light printing, plate making and facsimiles using electrophotographic technology. The present invention can be widely applied to such devices.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. In the following text, “part” means “part by mass”.

Production of Photoreceptor 1 Photoreceptor 1 was produced as follows.

  The surface of the cylindrical aluminum support was cut to prepare a cylindrical conductive support having a ten-point surface roughness Rz = 1.5 (μm).

<Intermediate layer>
The following intermediate layer dispersion was diluted twice with the same mixed solvent, and allowed to stand overnight, followed by filtration (filter; rigesh mesh 5 μm filter manufactured by Nihon Pall) to prepare an intermediate layer coating solution.

Polyamide resin CM8000 (manufactured by Toray Industries, Inc.) 1 part Inorganic particles: Titanium oxide (Number average primary particle size 35 nm: Titanium oxide treated with silica / alumina and methylhydrogenpolysiloxane) 3 parts Methanol 10 parts are mixed as a disperser Using a sand mill, batch dispersion was performed for 10 hours to prepare an intermediate layer dispersion.

  The said coating liquid was apply | coated by the dip coating method, and the intermediate | middle layer with a dry film thickness of 1.0 micrometer was formed on the said support body.

<Charge generation layer: CGL>
Charge generation material (CGM): oxytitanyl phthalocyanine (a titanyl phthalosine pigment having a maximum diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.3 ° in an X-ray diffraction spectrum by Cu-Kα characteristic X-ray) 24 parts polyvinyl butyral resin “S-LEC BL-1” (manufactured by Sekisui Chemical Co., Ltd.) 12 parts 2-butanone / cyclohexanone = 4/1 (v / v) 300 parts The above composition is mixed, dispersed using a sand mill, and charged. A generation layer coating solution was prepared. This coating solution was applied by a dip coating method to form a charge generation layer having a dry film thickness of 0.5 μm on the intermediate layer.

<Charge transport layer 1 (CTL1)>
Charge transport material (4,4′-dimethyl-4 ″-(α-phenylstyryl)
Triphenylamine) 225 parts Polycarbonate (Z300: Mitsubishi Gas Chemical Co., Ltd.) 300 parts Antioxidant (Irganox 1010: Nihon Ciba Geigy Co., Ltd.) 6 parts Dichloromethane 2000 parts Silicon oil (KF-54: Shin-Etsu Chemical Co., Ltd.) 1 part mixed And dissolved to prepare a charge transport layer coating solution 1. This coating solution was applied onto the charge generation layer by a dip coating method and dried at 110 ° C. for 70 minutes to form a charge transport layer 1 having a dry film thickness of 18.0 μm.

<Preparation of fluororesin fine particle dispersion 1>
The following PTFE particle dispersion was prepared using PTFE particles.

PTFE particles (PT1: average primary particle size 0.12 μm) 6 parts Toluene / tetrahydrofuran (2/8) 600 parts Fluorine comb-type graft polymer (trade name GF300, manufactured by Toagosei Co., Ltd.) 15 parts After premixing with ultrasonic dispersion and filtering with a 120 μm nylon mesh filter, basically the liquid collision dispersion process and filtration process (using a 20 μm nylon mesh filter) under high pressure as shown in FIG. The dispersion liquid was continuously circulated (dispersed by “Nanomizer” manufactured by Yoshida Kikai Kogyo Co., Ltd.) and dispersed to prepare a fluororesin fine particle dispersion 1. The discharge pressure at the time of dispersion liquid collision was performed under the condition of a constant pressure of 50 MPa and the average number of circulation of the dispersion liquid of 30 times, but the fluctuation of the discharge pressure was also stable in the range of 50M ± 10 MPa, and there was no clogging in the middle. I was able to disperse. The average particle diameter of the fluororesin fine particles after dispersion was 0.13 μm.

<Charge transport layer 2 (CTL2) = protective layer>
Fluorine-containing resin fine particle dispersion 1 621 parts Charge transport material (4,4′-dimethyl-4 ″-(α-phenylstyryl)
Triphenylamine) 300 parts Polycarbonate (Z300: manufactured by Mitsubishi Gas Chemical) 300 parts Antioxidant (Irganox 1010: manufactured by Ciba Geigy Japan) 12 parts THF: Tetrahydrofuran 2800 parts Silicon oil (KF-54: manufactured by Shin-Etsu Chemical Co., Ltd.) 4 parts Were mixed and dissolved to prepare a charge transport layer coating solution 2. This coating solution is basically applied onto the charge transport layer 1 using a coating apparatus and a drying apparatus (having a solvent vapor reservoir hood 51t and a drying hood 52t) having the circular coating head shown in FIGS. Drying (coating speed; 18 mm / sec) was performed, followed by further drying at 110 ° C. for 70 minutes to form a charge transport layer 2 having a dry film thickness of 2.0 μm.

Production of photoconductors 2 to 7 In production of photoconductor 1, the same procedure as for photoconductor 1 was performed except that the addition amount and dispersion conditions of the fluororesin fine particles and the solvent vapor reservoir hood length after application were changed as shown in Table 1. Photoconductors 2 to 7 were prepared. Both the dispersion of the fluororesin fine particle dispersions 2 to 7 and the fluctuation of the discharge pressure were stable in the range of 50 M ± 10 MPa, and could be dispersed without clogging on the way.

Production of Photoreceptor 8 In producing Photoreceptor 4, the solvent vapor reservoir hood 51t was removed from the coating and drying conditions of charge transport layer 2, and the photoreceptor immediately after application of charge transport layer 2 was directly passed through drying hood 52t and dried. A photoreceptor 8 was prepared in the same manner as the photoreceptor 4.

Production of Photoreceptor 9 In production of Photoreceptor 4, the filtration step was removed from the dispersion device, and the production of the fluororesin fine particle dispersion was dispersed by changing the initial setting of the discharge pressure at the time of dispersion collision from 50 MPa to 100 MPa. A photoreceptor 9 was produced in the same manner as the photoreceptor 4 except that the fluororesin fine particle dispersion 8 was used. As a result, clogging occurred in the disperser, and the disperser stopped in the middle of dispersion. After stopping the disperser, the flow path was washed and the dispersion was resumed. This operation was repeated three times to produce a fluororesin fine particle dispersion 9.

  Using the photoconductors 1 to 9, the area ratios A1, A2 and A3 of the fluororesin fine particles were determined from the cross-sectional image of the protective layer using the high resolution transmission electron microscope (HR-TEM) described above. The results are shown in Table 1.

In Table 1,
PTFE: Polytetrafluoroethylene resin fine particles << Image evaluation >>
Each of the obtained photoreceptors was set in a commercially available tandem type color copying machine C-3200A (manufactured by Xerox: color copying machine having a cleaner-less structure) and evaluated for copying. A total of 30,000 character images were printed, and at the start and every 5000 images, character images (evaluated by changing the size of kanji), halftone images, and solid images were evaluated for visual image defects. I did it.

As an image defect evaluation,
"Occurrence of voids" due to toner transfer failure
The presence or absence of character omission was observed visually.

Evaluation criteria are ◎ There is no occurrence of voids (good)
○ Although small hollows have occurred, character images can be accurately identified (useful)
× There is a gap in the character image that is judged incorrectly (unsuitable for practical use)
"Streak" due to poor toner cleaning
The presence or absence of streaks was visually observed.

Evaluation criteria: ○ No streak is seen in halftone (good)
× No streaks appear in halftone (unsuitable for practical use)
The results of image evaluation are summarized in Table 1. In the above evaluation, when the evaluation at the start was x, the evaluation of 30,000 durable prints was stopped (-).

  From Table 1, in the photoreceptors 2 to 6 in which the area ratios A1, A2, and A3 of the fluorine-containing resin fine particles satisfy the relational expression of the present invention, the occurrence of voids and streaks after initial and durability is improved. In the photosensitive member 1 having A2 of 0.01, the releasing effect of the protective layer is not improved, and the void is generated from the initial stage. Further, in the photoreceptor 7 having A2 of 0.40, the protective layer is easily damaged, and streaks are generated after the endurance. The photoreceptor 8 having A1 of less than A2 × 0.5 also does not improve the mold release effect on the surface, and has a void from the beginning. Further, in the photoconductor 9 having A3 / A2 of less than 0.5, the dispersibility of the fluorine-containing resin fine particles in the protective layer is poor, the protective layer is easily damaged, and a streak failure occurs after durability.

Production of Photoreceptor 10 Photoreceptor 10 was produced in the same manner as Photoreceptor 1 except that the fluororesin fine particles were changed to PTFE particles having an average primary particle size of 0.18 μm and added in an amount of 155 parts. Was made.

Production of Photoreceptor 11 Photoreceptor 11 was produced in the same manner as Photoreceptor 1 except that fluororesin fine particles were changed to PTFE particles having an average primary particle size of 0.05 μm and the addition amount was 140 parts. Was made.

  The photoconductor 10 and the photoconductor 11 were evaluated in the same manner as the photoconductor 1. The evaluation results are shown in Table 2.

  From Table 2, the photoreceptors 10 and 11 have the area ratios A1, A2, and A3 / A2 of the fluorine-containing resin fine particles satisfy the relational expression of the present invention, and the occurrence of voids and streaks after initial and durability Has been improved.

It is a perspective view which shows the whole structure of the continuous coating apparatus by this invention. It is sectional drawing which shows a positioning means and a circular application means. It is a perspective view of the said circular application means. It is sectional drawing seen from the upper part of the circular application means. It is sectional drawing which shows the said circular application means and dry hood. It is a partially broken perspective view of positioning means 30t. It is a figure of an example of the dispersion processing apparatus which circulates the liquid collision dispersion | distribution process and filtration process under high pressure. 1 is a schematic cross-sectional view of a cleaner-less image forming apparatus using an organic photoreceptor according to the present invention. 2 is a schematic cross-sectional view of a photoreceptor cartridge 2 that is detachable from an image forming apparatus. FIG. 1 is a cross-sectional configuration diagram of a cleaner-less color image forming apparatus using an organic photoreceptor of the present invention.

Explanation of symbols

1t, 1tA, 1tB, 1tC, 1tD Cylindrical support 10t Supply means 20t Conveyance means 21t, 22t Holding means 30t Positioning means 32t Air supply port 33t Exhaust port 40t Circular application means 41t Application head 50t Drying means 51t, 52t Drying hood 53t Dryer 54t Exhaust dryer 60t Separation discharge means (separator)
L Coating liquid 1 Image forming device 2 Photosensitive cartridge 3 Developer cartridge 4 Exposure device 5 Paper feeding device 6 Transfer roller 7 Fixing device 8 Paper discharge tray

Claims (6)

In an organic photoreceptor having an intermediate layer, a photosensitive layer and a protective layer on a conductive support, the protective layer contains fluorine-containing resin fine particles, and the area ratios A1, A2 of the fluorine-containing resin fine particles in the protective layer and An organic photoreceptor in which A3 satisfies the following relationship.
0.3 ≧ A2 ≧ 0.02
A2> A1 ≧ A2 × 0.5
1.0> A3 / A2 ≧ 0.5
However,
A1; area ratio A2 of fluororesin particles present in the protective layer up to a depth 0.5μm from the surface; area ratio of the fluororesin particles present in the protective layer from the surface up to a depth 3.0 [mu] m A3; Area ratio of isolated fluororesin fine particles present in the protective layer from the surface to a depth of 3.0 μm 2. The organic photoreceptor according to claim 1, wherein the number average primary particle size of the fluororesin fine particles is less than 0.2 μm. 3. The organophotoreceptor according to claim 1, wherein the protective layer is applied using a quantity-regulating coater. 4. The organophotoreceptor according to claim 3, wherein the amount-regulating coater is a circular slide hopper coater. In a cleanerless image forming apparatus having an organic photoconductor, a charging unit, an exposure unit, a developing unit, and a transfer unit, and collecting a toner image remaining on the organic photoconductor by the developing unit, the organic photoconductor An organic photoreceptor having an intermediate layer, a photosensitive layer and a protective layer on a conductive support, the protective layer containing fluorine-containing resin fine particles, and the area ratio A1 of the fluorine-containing resin fine particles in the protective layer; An image forming apparatus, wherein A2 and A3 satisfy the following relationship.
0.3 ≧ A2 ≧ 0.02
A2> A1 ≧ A2 × 0.5
1.0> A3 / A2 ≧ 0.5
However,
A1; area ratio A2 of fluororesin particles present in the protective layer up to a depth 0.5μm from the surface; area ratio of the fluororesin particles present in the protective layer from the surface up to a depth 3.0 [mu] m A3; Area ratio of isolated fluororesin fine particles present in the protective layer from the surface to a depth of 3.0 μm In a process cartridge used in a cleaner-less image forming apparatus having an organic photoconductor, a charging device, an exposure device, a developing device, and a transfer device, and collecting a toner image remaining on the organic photoconductor with a developing device. The organic photoreceptor is an organic photoreceptor having an intermediate layer, a photosensitive layer, and a protective layer on a conductive support, the protective layer containing fluorine-containing resin fine particles, and the fluorine-containing resin fine particles in the protective layer The area ratios A1, A2 and A3 satisfy the following relationship, and at least one of the organic photoreceptor and the charging unit, the exposure unit, the developing unit, and the transfer unit is integrally configured so that it can be taken in and out of the image forming apparatus. A process cartridge characterized by comprising.
0.3 ≧ A2 ≧ 0.02
A2> A1 ≧ A2 × 0.5
1.0> A3 / A2 ≧ 0.5
However,
A1; area ratio A2 of fluororesin particles present in the protective layer up to a depth 0.5μm from the surface; area ratio of the fluororesin particles present in the protective layer from the surface up to a depth 3.0Myumm A3; Area ratio of isolated fluororesin fine particles present in the protective layer from the surface to a depth of 3.0 μm

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