JP2008052304A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus mounted with a high-performance photoreceptor, having surface hydrophobicity increased, to the degree that a heater for heating the photoreceptor does not need to be provided. <P>SOLUTION: The image forming apparatus is provided with the photoreceptor having a photoconductive layer 4 and a surface protective layer 5 on an electrically conductive substrate; a charging means for providing charges to the photoreceptor; an exposure means for emitting light onto a charge area of the photoreceptor, to which charges are provided by the charging means; a developing means for developing an electrostatic latent image formed on the photoreceptor by the charging means and the exposure means with a toner for forming a toner image; a transfer means for transferring the toner image to a transfer material; and a cleaning means for remove toner remaining on the photoreceptor. The surface protective layer 5 in the photoreceptor is formed, by stacking a plurality of fluorinated amorphous layers 6e containing 12-35 at.% of fluorine in amorphous silicon carbide or amorphous carbon, and the surface protective layer 5 has surface free energy of 40 mN/m or smaller. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus equipped with a photoreceptor having a fluorine-containing surface protective layer made of amorphous silicon carbide or amorphous carbon.

  A photoconductor using amorphous silicon (hereinafter abbreviated as a-Si) as a photoconductive layer has already been commercialized. This a-Si photoconductor is formed on a conductive substrate by a glow discharge decomposition method. A charge injection blocking layer composed of hydrogenated amorphous silicon (hereinafter abbreviated as a-Si: H), a photoconductive layer composed of a-Si: H, and a hydrogenated amorphous silicon carbide (hereinafter referred to as hydrogen). And a surface protective layer made of amorphized amorphous silicon carbide (abbreviated as a-SiC: H).

  However, in the photoconductor having such a layer structure, an image defect called image flow has occurred particularly when printing is performed in a high humidity environment.

  In order to prevent the occurrence of this image flow, a technique has been proposed in which the photosensitive member is heated using a heater and the water causing the image is scattered, but this has improved the image flow. In addition, the charging ability of the photoconductor is reduced, the toner is fixed on the surface of the photoconductor, and the power consumption of the image forming apparatus is increased.

  In order to solve such a problem, the element ratio of the a-SiC: H surface protective layer and the dynamic indentation hardness of the free surface are regulated so that the surface is properly polished by a cleaning means or the like without using a heater. A technique for removing discharge products adsorbed on the surface layer and thereby eliminating image flow has been proposed (see Patent Document 1).

On the other hand, a surface protective layer made of hydrogenated amorphous carbon (hereinafter, hydrogenated amorphous carbon is abbreviated as aC: H) is laminated on the photoreceptor layer mainly composed of a-Si, and then contains fluorine. There is a technology that performs plasma discharge treatment with gas and forms functional groups such as CF and CF _{2 in the} vicinity of the surface, thereby improving hydrophobicity and suppressing environmental degradation by suppressing hydrophobic deterioration due to ozone irradiation. (See Patent Document 2).

Even if the surface of the film is etched when the plasma discharge treatment as described above is performed, a technique for forming a surface protective layer by alternately repeating film formation and etching a plurality of times has been proposed (see Patent Document 3). ).
Japanese Patent Laid-Open No. 9-204056 Japanese Patent Publication No. 7-3597 Japanese Patent Laid-Open No. 10-177265

  However, according to Patent Document 1, even if heating using a heater is not performed, a polishing unit such as an elastic roller (sliding roller) must be provided in an image forming apparatus equipped with this photosensitive member. This complicates the design and configuration, which decreases the manufacturing yield and deteriorates durability and reliability.

  On the other hand, in Patent Document 2, a surface protective layer made of aC: H can be provided, and plasma discharge treatment can be performed with a gas containing fluorine to increase hydrophobicity. A high hydrophobic performance that may not be provided has not been achieved.

  Patent Document 3 describes that the surface protective layer is formed of a BN film, and the film thickness etched by one etching is set to 20 mm or more. However, the BN film is formed by such a method. As a result, the deposition rate is lowered, and the manufacturing cost is increased. Furthermore, even if the surface protective layer is formed of a BN film, there are problems that the hardness is low, the durability is inferior, and the bonding state at the atomic level is unstable, resulting in variations in potential characteristics.

  As a result of diligent research in view of the above circumstances, the present inventors have formed an amorphous layer made of silicon carbide or carbon by a glow discharge method, and then etched the amorphous layer with a gas containing fluorine. It has been found that by forming a surface protective layer containing 12 to 35% of fluorine through the process, the hydrophobicity is remarkably increased, thereby eliminating the need to provide a heater for the photoreceptor in the image forming apparatus. In addition, the surface protective layer is appropriately cleaned after the transfer so that the surface free energy of the surface protective layer is maintained at 40 mN / m or less, and by setting such a value, good image quality can be obtained. It was.

  Accordingly, the present invention has been completed based on the above findings, and an object of the present invention is to provide an image forming apparatus equipped with a high-performance photoconductor whose surface hydrophobicity is increased to the extent that a heater for heating the photoconductor is not provided. There is.

  Another object of the present invention is to provide a high-reliability and low-cost photoconductor that achieves good image quality and eliminates variations in potential characteristics by defining the surface free energy of the surface protective layer in the photoconductor. An object is to provide an image forming apparatus.

  Still another object of the present invention is to define the surface free energy of the surface protective layer of the photoreceptor as a standard for manufacturing a high-quality image forming apparatus, thereby facilitating manufacturing management, thereby reducing manufacturing costs. As a result, an object is to provide a low-cost image forming apparatus.

  Furthermore, the object of the present invention is to simplify the structure by not providing a heater for the photosensitive member, to improve the manufacturing yield, and to obtain excellent durability by reducing the number of parts. An object of the present invention is to provide a cost-effective and highly reliable image forming apparatus.

  The image forming apparatus according to the present invention includes a photoconductor having a photoconductive layer and a surface protective layer on a conductive substrate, a charging unit for applying a charge to the photoconductor, and the charge applied by the charging unit. An exposure unit that irradiates light to a charged region of the photosensitive member; a developing unit that develops an electrostatic latent image formed on the photosensitive member by the charging unit and the exposing unit with toner; and a toner image. A transfer unit that transfers the toner image to a transfer material; and a cleaning unit that removes toner remaining on the photoconductor. The surface protective layer of the photoconductor includes fluorine on amorphous silicon carbide or amorphous carbon. It is formed by laminating a plurality of fluorinated amorphous layers containing 12 to 35 atomic%, and its surface free energy is 40 mN / m or less. It is characterized.

  In the image forming apparatus according to the present invention, the number of the fluorinated amorphous layers in the surface protective layer is preferably 2 to 15 layers.

  In the image forming apparatus according to the present invention, the toner preferably includes abrasive particles.

  In the image forming apparatus according to the present invention, the surface free energy of the surface protective layer in the photoreceptor is preferably 40 mN / m or less after electrostatic running for 5 hours after corona exposure.

  According to the present invention, in the photoreceptor, the fluorine content is specified to be 12 to 35 atomic% with respect to the surface protective layer made of fluorine-containing amorphous silicon carbide (a-SiC) or amorphous carbon (a-C). Therefore, the surface hydrophobicity is increased to the extent that a heater for heating the photoconductor is not provided, thereby preventing the occurrence of image flow and further variation in potential characteristics, resulting in high durability, high performance, and high reliability. A low-cost image forming apparatus can be provided.

  In addition, in the present invention, since the surface free energy of the surface protective layer is set to 40 mN / m or less, the pass / fail judgment is made in advance with the manufactured photoconductor rather than with the image forming apparatus equipped with the photoconductor. As a result, manufacturing management is facilitated and manufacturing costs are reduced, and as a result, a low-cost and highly reliable image forming apparatus can be provided.

  Further, according to the image forming apparatus of the present invention, the cleaning means for cleaning the surface protective layer of the photoconductor after the transfer is provided so that the surface free energy of the surface protective layer is 40 mN / m or less. Even after they are on the market, it is now possible to easily determine the quality level with surface free energy.

Structure of photoconductor The photoconductor is based on a laminated structure of at least a photoconductive layer and a surface protective layer on a conductive substrate. For further improvement in performance, for example, as shown in FIG. Such a laminated structure is used.

  This figure shows the layer structure of the photoreceptor 1 according to the present embodiment. A charge injection blocking layer 3 made of a-Si: H or the like and a photoconductive layer 4 made of a-Si: H or the like by a glow discharge decomposition method or the like. The surface protective layer 5 is laminated on the photoconductive layer 4 in order.

  Examples of the conductive substrate 2 include a metal conductor such as copper, brass, SUS, Al, and Ni, or a surface of an insulator such as glass and ceramic covered with a conductive thin film. The conductive substrate 2 may be a sheet-like, belt-like or web-like flexible conductive sheet, such as a metal sheet such as SUS, Al, Ni, or a polymer resin film such as polyester, nylon, polyimide, etc. A metal such as Al or Ni or a transparent conductive material such as tin oxide or indium tin oxide (ITO) or an organic conductive material coated thereon by vapor deposition is used.

  When the charge injection blocking layer 3 is made of a-Si: H or the like, oxygen or nitrogen is included to increase the forbidden band width, thereby increasing the barrier in terms of the function of blocking charge injection. Also good. In addition, the adhesion to the substrate can be improved by containing oxygen. However, since oxygen alone easily reacts with the silane gas to cause an explosion, inert nitrogen should be coexisted. Nitrogen monoxide (NO) gas or the like is actually used.

In addition to a-Si, the photoconductive layer 4 is made of a Se alloy such as Se, Se-Te, As ₂ Se ₃ or the like, and particles of II-VI group compounds such as ZnO, CdS, CdSe dispersed in a resin, polyvinyl carbazole, etc. This is a single layer type. Alternatively, the photoconductive layer 4 may be a function separation type in which the charge generation layer and the charge transport layer are separated.

  The surface protective layer 5 is composed of a fluorine-containing amorphous layer made of silicon carbide (SiC) or carbon (C), and the fluorine content is specified to be 12 to 35 atomic%.

  That is, the fluorine content should be 12 to 35 atomic%, preferably 18 to 26 atomic%, based on the total amount of various atoms constituting the surface protective layer 5, and if it is less than 12 atomic%, image flow occurs. If it exceeds 35 atomic%, the terminal portion increases in the bonded state, the interatomic network decreases, and the interatomic bonds such as C—C, Si—Si, and Si—C decrease, thereby weakening the film strength. As a result, film scraping and scratches occur.

  Moreover, in the present invention, it is important that the fluorine content is specified and the surface free energy of the surface protective layer 5 is 40 mN / m or less, preferably 35 mN / m or less. That is, as described above, when the treatment of containing a large amount of fluorine to 12 to 35 atomic% (plasmaization of a gas containing fluorine) is performed, the fluorine content may vary depending on the film formation conditions. Even if fluorine is contained in the range of 12 to 35 atomic%, image flow may occur. In addition, with respect to a standard that does not cause an image flow, it is better to make a pass / fail judgment in advance with the manufactured photoconductor 1 than with an image forming apparatus equipped with the photoconductor 1.

  Therefore, in view of such a situation, the produced photoreceptor 1 is judged to be good or bad by the surface free energy of the surface protective layer 5, and a product whose value is reduced to 40 mN / m or less is regarded as a good product. It has been found that if such a non-defective photoconductor is mounted on an image forming apparatus, it can be provided to the market without any quality problems, and the present invention has been completed.

  Such surface free energy is a dispersion force component, a polar force component, and a hydrogen bonding force component, and each surface free energy can be quantified. The surface free energy was obtained by a total value of these values. The measurement is analyzed by applying the extended Fowkes theory. Specifically, three kinds of liquids (dispersion force component, dipole component, and hydrogen bond force component surface free energy values are already known, α- The contact angle was measured by the droplet method using bromnaphthalene, water, and methylene iodide, and calculated based on the extended Fowkes theory based on the data.

  Thus, as described above, the fluorine content of the surface protective layer 5 is set to 12 to 35 atomic%, and the surface free energy is further reduced to 40 mN / m or less. The body could be made easily.

As for the surface protective layer 5, the dynamic indentation hardness of 90~500kgf / mm ^2, preferably it is desirable to 150~500kgf / mm ^2.

That is, the surface protective layer 5 regulates the fluorine content and the surface free energy, and it is preferable to increase the hardness, and a treatment to contain a large amount of fluorine to 12 to 35 atomic% (plasma of fluorine-containing gas) is performed. When the surface is etched, the hardness of the surface tends to vary, and the hardness may be low. Therefore, manufacturing conditions such as diluting the source gas with a diluent gas or increasing the high frequency power Therefore, the dynamic indentation hardness is increased to 90 kgf / mm ² or more. However, a high image quality is achieved by setting it to 500 kgf / mm ² or less. Further, by reducing the amount of etching once, the variation in film strength is reduced and the hardness is increased.

  Such dynamic indentation hardness is expressed by dynamic hardness using a DYNAMIC ULTRA MICRO HARDNESS TESTER (DUH-201 / 202) manufactured by Shimadzu Corporation. According to this measuring method, an indenter (triangular pan indenter) is pressed against the sample by an electromagnet, and the pressing force is increased at a constant rate up to a load of 0.1 g. The depth of penetration into the sample is automatically measured. The size of the indentation generated at that time is measured with a microscope, and the hardness value is obtained from the plastic deformation.

Method for forming surface protective layer 5 Next, a method for forming the surface protective layer 5 having the above structure will be described with reference to FIGS.

  FIGS. 3A to 3D are process diagrams showing a forming method A of the surface protective layer 5, and FIGS. 4A to 4E are views showing other forming methods B of the surface protective layer 5. FIGS. It is process drawing.

  [Regarding Method A for Forming Surface Protective Layer 5] Steps (a) to (d) in FIG. 3 will be described below.

Step (a): An amorphous layer 6a made of silicon carbide (SiC) or carbon (C) is formed on the photoconductive layer 4 by glow discharge.

(B) Step: Etching with a gas containing fluorine. This etching process uses a gas such as CF ₄ gas, NF ₃ gas, SF ₆ gas, C ₂ F ₆ gas, F ₂ gas, ClF ₃ gas, CHF ₃ gas, CH ₂ F ₂ gas, and CH ₃ F gas. If, for example, CF ₄ gas is used, plasma is generated under the conditions of a degree of vacuum of 0.35 torr, a substrate temperature of 270 ° C., and a high frequency power of 200 W, and as a result, fluorine gradually enters from the surface of the amorphous layer 6a to the inside. At the same time, the surface is etched. Reference numeral 6b denotes a region of the amorphous layer 6a where fluorine does not enter (fluorine non-intrusion region), 6c denotes a fluorinated region, and 6d denotes a region where the upper layer region of the amorphous layer 6a is etched (etching region).

  It can also be seen that the etching rate affects the film quality, and it is desirable to set the etching rate to 50 to 500 liters / minute, preferably 100 to 250 liters / minute, thereby reducing the damage to the film surface and reducing film peeling. Image defects and the like do not occur and the film is sufficiently fluorinated.

In the fluorinated region 6c, the hydrogen atom is replaced with a fluorine atom or the fluorine atom is bonded to the terminal portion due to the etching treatment, and a functional group such as C—F, C—F ₂ , or C—F _{3 is used.} Is produced, and in particular, a large amount of C—F ₂ is produced. And these products have a significant effect on increasing hydrophobicity. The amount of each functional group is measured with a Fourier transform infrared spectrophotometer.

  Step (c): The fluorinated region 6c is formed by the etching process in the step (b). By further advancing the etching process and at the same time further increasing the etching region 6d, the substantially non-fluorine intruding region 6b The etching process is advanced to the extent that it does not occur. Thus, etching is performed until the entire amorphous layer 6a is fluorinated to form a fluorinated amorphous layer 6e.

  (D) Step: The steps (a) to (c) are set as one cycle, and this cycle is repeated to laminate a plurality of fluorinated amorphous layers 6e. For example, the amorphous layer 6a is formed to a thickness of 2000 mm in the step (a), and is made 1000 to 1500 mm by the steps (b) and (c). The surface protective layer 5 is formed by repeating such a cycle five times, that is, by laminating five fluorinated amorphous layers 6e.

  Thus, according to the formation method A of the surface protective layer 5, the formation of a C—F functional group having a large binding energy significantly reduces the surface free energy and has excellent oxidation resistance. The product is less likely to adhere, and the force acting on the developer is almost electrostatic attraction, improving transferability, and as a result, no image blur occurs. And even if the discharge product is slightly adhered, the surface hardness is increased, for example, even if a toner containing abrasive particles is used, the surface is moderately polished and the discharge product adsorbed on the surface layer, etc. Can be removed. Furthermore, cleaning can be easily performed with a cleaning means or paper, and toner adhesion can be suppressed or prevented.

  If the surface protective layer 5 is formed by the single-layered fluorinated amorphous layer 6e by the steps (a) to (c), the etching process in the step (b) becomes longer and the surface of the fluorinated region 6c becomes rough. Fluoromorphic amorphous layer with a small film thickness by reducing the film thickness of the amorphous layer 6a and shortening the etching process time, while the film adhesion tends to be inferior or the electrophotographic characteristics tend to deteriorate. 6e is formed, and by laminating such a fluorinated amorphous layer 6e, the surface roughness of each fluorinated amorphous layer 6e is reduced, the adhesion of the film is improved, and the electrophotographic characteristics are improved. it can. Desirably, a fluorinated amorphous layer 6e of 2 to 15 layers (number of cycles in step (d): 2 to 15), optimally 3 to 10 layers (number of cycles in step (d): 3 to 10) is laminated. By doing so, the surface protective layer 5 is comprised.

  [Regarding Method B for Forming Surface Protective Layer 5] Next, another method B for forming the surface protective layer 5 as shown in FIG. 4 will be described. In this forming method B, the step (c) is omitted as compared with the forming method A described above. That is, although the fluorinated region 6c is formed by the etching process in the step (b), the etching process is advanced to such an extent that the fluorine non-entry region 6b remains. Then, in the next step (e), the steps (a) and (b) are set as one cycle, and this cycle is repeated to alternately stack the fluorinated regions 6c and the non-fluorine-entry regions 6b, thereby protecting the surface. Layer 5 is formed.

  As described above, the fluorine non-intrusion region 6b may exist in the surface protective layer 5. However, when the fluorine non-intrusion region 6b does not exist as in the above-described formation method A, the reliability of film formation is improved and stable. Electrophotographic characteristics can be obtained, and the production yield can be increased.

  In both the formation method A and the formation method B of the surface protective layer 5, the film thickness of the amorphous layer 6a may be 0.01 to 1 μm, preferably 0.05 to 0.5 μm. The film is etched with an appropriate amount, and fluorination of the entire film is easy.

  Also for the fluorinated region 6c, the film thickness should be 0.005 to 0.5 μm, preferably 0.03 to 0.3 μm, and if within this range, both durability and potential characteristics will be improved. It's okay.

  And it is good to make the film thickness of the surface protective layer 5 formed in this way into 0.1-1.5 micrometer, Preferably it is 0.2-1.0 micrometer, if it is in this range, durability and electric potential characteristics It is good in terms of enhancing both.

  Further, regarding the formation method B, the film thickness of the fluorine non-intrusion region 6b is preferably 0.001 to 0.05 μm, preferably 0.001 to 0.01 μm. Etching can provide a uniform film thickness, a stable film thickness, and no image flow.

  Also in this forming method B, the surface protective layer 5 may be formed by laminating the single fluorinated region 6c and the single fluorine non-intruding region 6b by the steps (a) and (b). In order to prevent roughening of the surface of the control region 6c, preferably 2 to 15 layers [number of cycles in the step (e): 2 to 15], optimally 3 layers to 10 layers [number of cycles in the step (e): 3 To 10], the surface protective layer 5 is formed.

[Material of amorphous layer 6a]
(A) The amorphous layer 6a formed and formed in the step is made of silicon carbide (SiC) or carbon (C), but the a-C film is smaller in hardness than the a-SiC film. It is good to form. Therefore, the X value of the atomic composition ratio Si _X C _1-X is 0.5 or less, preferably 0.3 or less, and optimally 0.1 or less. And corona resistance improves by making it contain in this way reducing Si. However, the hardness of the a-C film can be increased by gas dilution, but the degree of hardness obtained with the a-SiC film cannot be obtained.

Configuration of image forming apparatus Fig. 2 shows an image forming apparatus 7 according to the present invention, 8 is a photoconductor, and a corona charger 9 is applied to the peripheral surface of the photoconductor 8, and light is irradiated after the charging. An exposure device 10 (LED head), a developing device 12 having a toner 11 for forming a toner image on the surface of the photoreceptor 8, a transfer device 14 for transferring the toner image to a transfer material 13, and a transfer thereof A cleaning unit 15 including a blade and a brush for cleaning the surface of the photoreceptor later, and a charge eliminating unit 16 for removing the residual electrostatic latent image after the transfer are provided. Reference numeral 17 denotes a fixing device for fixing the toner image transferred to the transfer material 13 by heat or pressure. The toner 11 may contain abrasive particles such as ceramic particles such as alumina, titanium oxide, and silica, thereby improving the cleaning property.

  In the Carlson method, the following processes (1) to (6) are repeated.

(1) The peripheral surface of the photoconductor 8 is charged by the corona charger 9.

(2) By exposing the image with the exposure device 10, an electrostatic latent image as a potential contrast is formed on the surface of the photoconductor 8.

(3) The electrostatic latent image is developed by the developing machine 12. By this development, black toner adheres to the surface of the photoreceptor due to electrostatic attraction with the electrostatic latent image, and is visualized.

(4) The toner image on the surface of the photoreceptor is electrostatically transferred by applying an electric field having a polarity opposite to that of the toner from the back surface of the transfer material 13 such as paper, whereby an image is obtained on the transfer material 13.

(5) The surface of the photosensitive member is cleaned by the cleaning means 15 including a blade or a brush.

(6) The entire surface of the photosensitive member is exposed with strong light, and the remaining electrostatic latent image is removed by the charge eliminating means 16.

  Although the image forming apparatus 7 has a printer configuration, if an optical system such as a lens or a mirror that transmits reflected light from a document is used instead of the exposure device 10, an image forming apparatus having a configuration of a copying machine is obtained. The image forming apparatus 7 uses normal dry development, but can also be applied to a liquid developer used for wet development.

  In the image forming apparatus 7 of the present invention, by providing the cleaning unit 15, the residual toner on the surface of the photoreceptor can be mechanically removed by the cleaning unit 15. Usually, when the cleaning means 15 is not used, the surface of the photoconductor is not mechanically polished unless the toner 11 further contains abrasive particles such as ceramic particles such as alumina, titanium oxide, and silica. Although the surface free energy of the layer 5 tends to increase, the increase of the surface free energy can be suppressed by using the cleaning means 15 in this way. In the present invention, not only the surface free energy of the surface protective layer 5 of the produced photoreceptor 1 is lowered to 40 mN / m or less, but also after being mounted on the image forming apparatus 7 and continuously used, By cleaning the surface of the photoconductor with the cleaning unit 15 so that the surface free energy of the surface protective layer 5 of the photoconductor 1 is 40 mN / m or less, high image quality without image drift can be stably obtained over a long period of time. I was able to.

(Example 1) On a cylindrical substrate made of Al having a purity of 99.9%, charge is obtained by a glow discharge decomposition method under film forming conditions as shown in Table 1 (this condition is a value in one chamber). The injection blocking layer 3 and the photoconductive layer 4 were laminated.

Next, the surface protective layer 5 is provided by the forming method A. First, an amorphous layer 6a made of carbon (C) is formed to a thickness of 2000 mm according to the film forming conditions in step (a) shown in Table 2.

Next, an etching process is performed under the conditions of step (b) shown in Table 3.

  By continuing the etching process of Table 3, the etching process is advanced to such an extent that there is substantially no fluorine non-intrusion region 6b, thereby forming a fluorinated amorphous layer 6e with a thickness of 1000 mm (step (c)).

Thereafter, the process (d), that is, the processes (a) to (c) is set as one cycle, and this cycle is repeated five times, thereby stacking five fluorinated amorphous layers 6e, and the surface free energy is 16.2 mN / m. The surface protective layer 5 having a dynamic indentation hardness of 250 kgf / mm ² and a fluorine content of 24 atomic% was formed.

The photoreceptor thus obtained is mounted on the image forming apparatus 7 (Ecosys LS-3550, manufactured by Kyocera Corporation, dry development: toner average particle diameter 8 μm). The cleaning unit 15 used in the image forming apparatus 7 uses a blade and a rubbing roller. Switching of the heater for heating the photoconductor provided in the apparatus 7 was always turned OFF, and the photoconductor was not heated. Then, the image was formed by the Carlson method, and a running test of 300,000 sheets was performed (A4 size paper was used to perform 5% printing. The following are all the same printing conditions). When measured, the results shown in Table 4 (surface protective layer comprising aC: H: F) were obtained.

  The image flow is left for 8 hours in an environment of 33 ° C and 85% humidity, and the image quality is evaluated in three stages. The circle indicates that there is no change in the image, and the triangle indicates that a portion of the image flows. The x mark represents a case where an image flows over the entire surface.

  The image quality is evaluated in three stages, with black solid, white solid, and halftone images. ○ indicates that there is no problem with fogging in black solid density / white solids, and there are no streaks in the halftone image. △ mark indicates a case where a stripe is generated in a part of the halftone image, and X mark indicates a case where a stripe is generated over the entire surface of the halftone image.

As a comparative example, a surface protective layer made of a-SiC: H and a surface protective layer made of a-C: H were formed under film forming conditions as shown in Tables 5 and 6, and other layer configurations were shown in Table 1. Each photoconductor was prepared as described above and evaluated in the same manner. The results shown in Table 4 were obtained. Note that the amount of SiH ₄ gas shown in Table 6 is gradually decreased from 8.3 SCCM to 2.5 SCCM.

Such a surface protective layer made of a-SiC: H has a surface free energy of 43 mN / m, a dynamic indentation hardness of 350 kgf / mm ² , and a surface protective layer made of a-C: H has a surface free energy of The dynamic indentation hardness was 38 kgf / mm ² .

  As is clear from the results shown in Table 4, it can be seen that both the image flow and the image quality are improved by forming the surface protective layer made of aC: H: F as in the present invention.

(Example 2) Various photoreceptors A to G in which the amount of fluorine of the surface protective layer 5 was defined were prepared by changing the RF power as shown in Table 7 for the photoreceptor obtained in (Example 1). .

When these photoconductors were mounted on the image forming apparatus 7 and image flow and image quality were evaluated and measured, results shown in Tables 8 and 9 were obtained.

  As is clear from these tables, the photoconductors C to F are excellent in both image flow and image quality. However, since the photoconductor G has an increased fluorine content, the number of terminal portions is increased in the bonded state, the number of atoms is less, and the film strength is weakened. In all of the photoreceptors C to F, the surface free energy of the surface protective layer 5 is 40 mN / m or less.

  (Example 3) Two types of photoconductors 1 and 2 were prepared by changing the film forming conditions for the photoconductors prepared in (Example 1). For each of these photoreceptors 1 and 2, each surface protective layer 5 is provided by forming method A.

First, the amorphous layer 6a made of carbon (C) is formed to a thickness of 2000 mm according to the film forming conditions in step (a) shown in Table 10.

Next, an etching process is performed under the conditions of step (b) shown in Table 11.

  By continuing the etching process of Table 11, the etching process is advanced to the extent that there is substantially no fluorine non-intrusion region 6b through the step (c), thereby forming a fluorinated amorphous layer 6e with a thickness of 1000 mm.

Thereafter, the process (d), that is, the processes (a) to (c) is set as one cycle, and this cycle is repeated five times to laminate five fluorinated amorphous layers 6e. The surface protective layer 5 having a hardness of 280 kgf / mm ² and a fluorine content of 18 atomic% is formed, and the photoreceptor 2 has a surface with a dynamic indentation hardness of 250 kgf / mm ² and a fluorine content of 25 atomic%. A protective layer 5 was formed.

  The photoreceptor thus obtained is mounted on the image forming apparatus 7 (Ecosys LS-3550, manufactured by Kyocera Corporation, dry development: toner average particle diameter 8 μm). The cleaning unit 15 used in the image forming apparatus 7 used a blade and a rubbing roller as in Example 1. Switching of the heater for heating the photoconductor provided in the apparatus 7 was always turned OFF, and the photoconductor was not heated.

Further, a surface protective layer having a thickness of 2000 mm was formed on the photosensitive members 4, 5, and 6 of the comparative example under the film forming conditions as shown in Table 12. These surface protective layers were not etched.

Then, the surface free energy was measured by performing electrostatic running (charge amount of 0.3 μC / cm ² ) for each photosensitive member 1 to 6 in the initial stage and the corona exposure for 5 hours. Results as shown in FIG. 13 were obtained. The photoconductor 3 corresponds to the photoconductor prepared in (Example 1).

  As is apparent from this table, according to each of the photoreceptors 1 to 3, the initial surface free energy is 40 mN / m or less, and the surface free energy after 5 hours is also 40 mN / m or less. On the other hand, for each of the photoconductors 4 to 6, the initial surface free energy is 40 mN / m or less, but the surface free energy after 5 hours exceeds 40 mN / m.

Each of the photoconductors 1 to 6 was mounted on the image forming apparatus 7 and the image flow and image quality were evaluated and measured. As a result, the results shown in Table 14 were obtained.

  As is apparent from this table, it can be seen that the use of the photoconductors 1 to 3 is excellent in both image flow and image quality.

  (Example 4) (Example 1) to (Example 3) are cases where a surface protective layer made of a-C: H: F is formed, but hereinafter, a surface made of a-SiC: H: F instead. A case where a protective layer is formed will be described.

The charge injection blocking layer 3 and the photoconductive layer 4 are laminated under the film forming conditions shown in Table 1, and the surface protective layer 5 made of a-SiC: H: F is provided thereon by the forming method A. In that case, the amorphous layer 6a made of a-SiC: H is formed to a thickness of 2000 mm according to the film forming conditions in step (a) shown in Table 15.

Next, an etching process is performed under the conditions of step (b) shown in Table 16.

  By continuing the etching process of Table 16, the etching process is advanced to the extent that there is substantially no fluorine non-intruding region 6b through the step (c), thereby forming a fluorinated amorphous layer 6e having a thickness of 1000 mm.

Thereafter, the process (d), that is, the processes (a) to (c) is set as one cycle, and this cycle is repeated five times to thereby laminate five fluorinated amorphous layers 6e, and the dynamic indentation hardness is 300 kgf / mm. ² and the surface protective layer 5 having a fluorine content of 21 atomic% was formed.

The photoreceptor thus obtained is mounted on the image forming apparatus 7 (Ecosys LS-3550, manufactured by Kyocera Corporation, dry development: toner average particle diameter 8 μm). The cleaning unit 15 used in the image forming apparatus 7 uses a blade and a rubbing roller. Switching of the heater for heating the photoconductor provided in the apparatus 7 was always turned OFF, and the photoconductor was not heated. Then, an image was formed by the Carlson method, 300,000 running tests were performed, and image flow and image quality were measured. As a result, the results shown in Table 17 (surface protective layer made of a-SiC: H: F) were obtained. Obtained.

  As comparative examples, a surface protective layer made of a-SiC: H and a surface protective layer made of aC: H shown in (Example 1) will be described.

  As is clear from the results shown in Table 17, it can be seen that the formation of the surface protective layer made of a-SiC: H: F as in the present invention significantly improves both the image flow and the image quality. .

(Example 5) Various photoconductors A to G in which the amount of fluorine of the surface protective layer 5 was specified were produced by changing the RF power as shown in Table 18 for the photoconductor obtained in (Example 4). .

When these photoconductors were mounted on the image forming apparatus 7 and image flow and image quality were evaluated and measured, the results shown in Table 19 and Table 20 were obtained.

  As is clear from these tables, the photoconductors C to F are excellent in both image flow and image quality. However, since the photoconductor G has an increased fluorine content, the number of terminal portions is increased in the bonded state, the number of atoms is less, and the film strength is weakened. In all of the photoreceptors C to F, the surface free energy of the surface protective layer 5 is 40 mN / m or less.

  (Example 6) Two types of photoconductors 1 and 2 were prepared by changing the film forming conditions of the photoconductors prepared in (Example 4). For each of these photoreceptors 1 and 2, each surface protective layer 5 is provided by forming method A.

First, an amorphous layer 6a made of silicon carbide (SiC) is formed to a thickness of 2000 mm according to the film forming conditions in step (a) shown in Table 21.

Next, an etching process is performed under the conditions of (b) step shown in Table 22.

  By continuing the etching process of Table 22, the (c) step is performed, so that the etching process is advanced to such an extent that there is substantially no fluorine non-intrusion region 6b, thereby forming a fluorinated amorphous layer 6e having a thickness of 1000 mm.

Thereafter, the process (d), that is, the processes (a) to (c) is set as one cycle, and this cycle is repeated five times to laminate five fluorinated amorphous layers 6e. The surface protective layer 5 having a hardness of 290 kgf / mm ² and a fluorine content of 18 atomic% is formed, and the photoreceptor 2 has a surface with a dynamic indentation hardness of 230 kgf / mm ² and a fluorine content of 23 atomic%. A protective layer 5 was formed.

  The photoreceptor thus obtained is mounted on the image forming apparatus 7 (Ecosys LS-3550, manufactured by Kyocera Corporation, dry development: toner average particle diameter 8 μm). The cleaning unit 15 used in the image forming apparatus 7 used a blade and a rubbing roller as in Example 1. Switching of the heater for heating the photoconductor provided in the apparatus 7 was always turned OFF, and the photoconductor was not heated.

Further, a surface protective layer having a thickness of 2000 mm was formed on the photoconductors 4, 5, 6 of the comparative example under the film forming conditions as shown in Table 23. These surface protective layers were not etched.

Then, with respect to each of the photoreceptors 1 to 6, the surface free energy in the initial stage and the electrostatic running (charge amount of 0.3 μC / cm ² ) by corona exposure for 5 hours were performed, and the change with time was measured. However, the results shown in Table 24 were obtained. The photoconductor 3 corresponds to the photoconductor prepared in (Example 4).

  As is apparent from this table, according to each of the photoreceptors 1 to 3, the initial surface free energy is 40 mN / m or less, and the surface free energy after 5 hours is also 40 mN / m or less. On the other hand, for each of the photoreceptors 4 to 6, both the initial surface free energy and the surface free energy after 5 hours exceed 40 mN / m.

Each of the photoconductors 1 to 6 was mounted on the image forming apparatus 7 and the image flow and image quality were evaluated and measured. As a result, the results shown in Table 25 were obtained.

  As is apparent from this table, the use of each of the photoreceptors 1 to 3 is excellent in both image flow and image quality.

FIG. 3 is a cross-sectional view showing a layer structure of a photoreceptor according to an embodiment of the present invention. 1 is a schematic view of an image forming apparatus of the present invention. (A), (b), (c) and (d) are process diagrams showing a method for forming a surface protective layer according to the present invention. (A), (B) and (E) are process diagrams showing another method of forming the surface protective layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 8 Photoconductor 2 Conductive substrate 3 Charge injection blocking layer 4 Photoconductive layer 5 Surface protective layer 6a Amorphous layer 6b Fluorine non-intrusion area 6c Fluorinated area 6d Etched area 6e Fluorinated amorphous layer 7 Image forming apparatus 9 Corona charger DESCRIPTION OF SYMBOLS 10 Exposure device 12 Developing device 14 Transfer device 15 Cleaning means 16 Static elimination means 17 Fixing device

Claims (4)

A photoconductor having a photoconductive layer and a surface protective layer on a conductive substrate, a charging unit for applying a charge to the photoconductor, and light applied to a charged region of the photoconductor to which a charge is applied by the charging unit. Exposure means for irradiating the toner, developing means for developing the electrostatic latent image formed on the photosensitive member with the toner by the charging means and the exposure means with toner, and transferring the toner image to the transfer material Transfer means for cleaning, and cleaning means for removing toner remaining on the photoreceptor,
The surface protective layer in the photoreceptor is formed by laminating only a plurality of fluorinated amorphous layers containing 12 to 35 atomic% of fluorine in amorphous silicon carbide or amorphous carbon, and the surface free energy is 40 mN / An image forming apparatus, wherein m or less. The image forming apparatus according to claim 1, wherein the number of laminated fluorinated amorphous layers in the surface protective layer is 2 to 15 layers. The image forming apparatus according to claim 1, wherein the toner includes abrasive particles. 4. The image forming apparatus according to claim 1, wherein the surface free energy of the surface protective layer in the photoconductor is 40 mN / m or less after electrostatic running for 5 hours after corona exposure.

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