JP2015175897A - Protective layer forming apparatus, image forming apparatus, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protective layer forming apparatus configured to improve application of an image carrier protective agent and a function of preventing toner passing-through, by increasing pressure per unit area even when the amount of a protective leveling member nipping an image carrier surface is small.SOLUTION: A protective layer forming apparatus includes at least: an image carrier protective agent; a protective agent supply member for supplying the image carrier protective agent to a surface of an image carrier; and a protective agent leveling member for leveling the image carrier protective agent supplied on the image carrier. The protective agent leveling member includes a contact section with a triangular cross section having a vertex angle D of 15-80 degrees. The contact section comes into contact with the image carrier surface.

Description

  The present invention relates to a protective layer forming apparatus, an image forming apparatus, and a process cartridge.

  An image forming apparatus using an electrophotographic process includes a photoconductor as an image carrier, charges the surface of the photoconductor by discharging, and charges the surface of the photoconductor to form an electrostatic latent image. Then, toner is supplied to the electrostatic latent image to make it visible, and the visible image formed on the surface of the photoreceptor is transferred to the surface of the transfer paper, and then fixed and discharged. Since untransferred toner or the like remains on the surface of the photoconductor after the transfer of the visible image, the photoconductor surface is cleaned by a cleaning unit so that they do not adversely affect the next image formation. Prepared for.

  In the charging step, an electrical stress is applied to the photoreceptor, and the state of the photoreceptor surface is greatly changed. This electrical stress is particularly prominent in the contact charging method and the proximity charging method that involve a discharge phenomenon near the surface of the photoreceptor. In these charging methods, many active species and reaction products are generated on the surface of the photoreceptor, and many active species and reaction products generated in the atmosphere in the discharge region are adsorbed on the surface of the photoreceptor. For this reason, the adhesion force on the surface of the photosensitive member is increased, the cleaning property is deteriorated, and foreign matter adhesion (filming) is likely to occur. In particular, in the charging method in which the AC component is superimposed on the DC component, the influence on the material in the surface layer of the photoconductor is large, such as a decrease in molecular weight due to resin molecular chain breakage, a decrease in the degree of entanglement of polymer chains, and evaporation of the resin Chemical degradation occurs. Under such circumstances, when the surface of the photoconductor is mechanically rubbed by the cleaning means, the wear of the photoconductor is further promoted.

As the cleaning means, a cleaning blade made of an elastic material such as rubber or a cleaning brush formed of a fiber made of synthetic resin in a brush shape is rubbed against the surface of the photoconductor to remove deposits on the photoconductor such as untransferred toner. What is removed is generally known. However, the cleaning blade and the cleaning brush are also worn over time.
Therefore, in order to prevent chemical deterioration of the photoconductor, and to reduce frictional resistance acting between the photoconductor and the cleaning unit, to prevent wear due to sliding between the photoconductor and the cleaning unit. In addition, a technique such as applying a protective agent to the surface of the photoreceptor is taken. If the amount of the protective agent applied to the surface of the photoreceptor is too small, uneven coating occurs, and defective cleaning occurs in a portion where the protective agent is not sufficiently applied, or wear of the cleaning means progresses. On the other hand, when there is too much quantity of a protective agent, the space of a protective agent will become large and a machine will enlarge. Further, the protective agent contaminates the surface of the charging roller that is close to or in contact with the surface of the photoconductor, so that uniform charging is not performed and streaky image defects may occur. Therefore, it is important to apply an appropriate amount of protective agent to the surface of the photoreceptor.

For this reason, in order to apply an appropriate amount of the protective agent to the surface of the photosensitive member, for example, the density of the brush roller fiber to which the protective agent is applied is regulated, or the image carrier protective agent is pressed against the brush roller. Proposals have been made to provide an imparting member to define the applied pressure or to define the amount of biting of the brush roller into the surface of the photoreceptor (see Patent Documents 1 and 2).
In order to optimize the amount of the protective agent applied to the photoreceptor, a method of controlling the amount of the protective agent applied based on image data information has been proposed (see Patent Document 3).

  Incidentally, in recent years, in image forming apparatuses using an electrophotographic process, there has been an increasing demand for higher image quality, and in particular, in order to realize high-definition color image formation, toner particles have been made smaller and spherical. ing. The reproducibility of dots is improved by reducing the particle size, and the developability and transferability can be improved by making the particles spherical. Since it is very difficult to produce such a small particle size and spherical toner by the conventional kneading and pulverization method, the polymerization produced by suspension polymerization method, emulsion polymerization method, dispersion polymerization method, etc. Toner is being adopted.

  However, when the toner having a spherical shape and a small particle size is used, there are some problems in cleaning the residual toner remaining on the photoreceptor after the transfer. One of them is that it is difficult to clean a toner having a spherical shape and a small particle size by using a blade cleaning method generally used. The cleaning blade removes the toner while rubbing the surface of the photoconductor, but the edge portion of the cleaning blade is deformed by the frictional resistance with the photoconductor, so that a minute space is formed between the photoconductor and the cleaning blade. . The smaller the toner particle size, the easier it is to enter this space. Then, the closer to the spherical shape, the smaller the rolling frictional force, so that the toner starts to roll in the space between the photosensitive member and the cleaning blade, passes through the cleaning blade and leads to poor cleaning.

  As a measure for preventing such a cleaning failure, a method of increasing the contact pressure of the cleaning blade to the surface of the photosensitive member is taken. For example, a method has been proposed in which the surface pressure of the cleaning blade on the surface of the photosensitive member is increased by making the ridge line portion in contact with the photosensitive member of the cleaning blade an obtuse angle (see Patent Document 4). However, the frictional force between the surface of the photoreceptor and the cleaning blade increases due to the increase in surface pressure. As a result, damage and wear of the cleaning blade and wear of the photoconductor may be more likely to proceed. Also, when the surface pressure is high, stick slips that cause the cleaning blade to oscillate irregularly are likely to occur, and blade squealing and blade turning due to stick slips are likely to occur. Also from the viewpoint of suppressing the occurrence of stick-slip, it is becoming more important to apply an appropriate amount of a protective agent to the surface of the photoconductor to reduce the coefficient of friction on the surface of the photoconductor.

  In addition, even if an appropriate amount of protective agent is applied to the surface of the photoconductor, if the layer is not uniformly thinned, the coefficient of friction on the surface of the photoconductor becomes non-uniform, so that the transfer of the toner image is good. This is not performed, and various abnormal images such as a void in an image portion called “insect bite” or a blurred image called “bottle” are generated.

  Here, the following two patterns are considered as the positional relationship between the two steps of applying the protective agent and cleaning the residual toner after transfer. That is, there are two patterns: a relationship of post-application cleaning in which the protective agent is applied first and cleaning is later, and a relationship of post-cleaning application in which the cleaning is applied first and the protective agent is applied later. Different.

  In the pattern to be cleaned after the application, a protective agent is applied to the surface of the photosensitive member in which the toner remains without being removed. Here, the portion corresponding to the character portion of the image originally carried on the surface of the photosensitive member has a large amount of residual toner on the surface of the photosensitive member even after transfer to a transfer material such as paper, and the portion other than the character portion is almost all. There is no residual toner. A large amount of the protective agent together with the toner is scraped off by the application brush and a cleaning blade at the cleaning position from a place where the residual toner is attached in a large amount. Therefore, the amount of the protective agent applied on the surface of the photoreceptor after passing through the cleaning position is biased. If a uniform protective agent layer cannot be formed on the surface of the photoreceptor, the surface static friction coefficient μ may be biased or not low enough to transfer the toner. As a result, uneven transfer may occur, and various abnormal images such as insect bite and vomit may occur.

  On the other hand, in the pattern to be applied after cleaning, since the protective agent after application is not scraped off by the application brush and the cleaning blade, the above-described problems in the configuration of cleaning after application can be prevented. However, when the protective agent is simply applied to the surface of the photoconductor, the granular protective agent remains on the photoconductor, and this contaminates the charging member when it passes through the charging member. Further, if a uniform protective agent layer cannot be formed on the surface of the photoreceptor, the static friction coefficient μ of the surface becomes non-uniform or does not become a sufficiently low value for transferring the toner, resulting in uneven transfer. Abnormal images such as biting and vomit occur.

  Therefore, in order to form a uniform protective agent layer on the surface of the photosensitive member, a blade is used as a protective agent leveling member downstream of the member to apply the protective layer, as shown in FIG. A configuration has been proposed in which the leading edge portion of this is brought into contact with the photosensitive member from the trailing direction (see Patent Documents 5 and 6).

  Here, FIG. 1 is a schematic view showing an example of a conventional protective layer forming apparatus. In FIG. 1, a protective layer forming apparatus 500 having a conventional protective agent leveling member 520 is shown together with a photosensitive drum 550 and a cleaning means 560 that rotate in the rotation direction indicated by an arrow AD1 in FIG. ing. The protective layer forming apparatus 500 includes a protective agent applying apparatus 510 and a protective agent leveling member 520.

  The cleaning unit 560 includes a cleaning blade 561 and a blade holding member 562. The blade holding member 562 is fixed to the case 501 of the protective layer forming apparatus 500. The cleaning blade 561 is cantilevered by the blade holding member 562, and its free end abuts against the surface of the photosensitive drum 550 from the counter direction with respect to the movement direction of the outer peripheral surface 551 of the photosensitive drum 550 after transfer. Then, the cleaning blade 561 rubs the outer peripheral surface 551 of the photosensitive drum 550 after the transfer, and removes the deposits represented by the residual toner remaining on the outer peripheral surface 551.

  The protective agent coating device 510 includes a brush roller 511 as a protective agent supply member, an image carrier protective agent 512, and a pressing member 513. A brush roller 511 serving as a protective agent supply member is accommodated in the case 501 so that the tip of the brush is pressed against the photosensitive drum 550 at a position downstream of the cleaning unit 560 in the rotation direction of the photosensitive drum 550. . The brush roller 511 is rotationally driven in a rotational direction opposite to the rotational direction of the photosensitive drum 550, as indicated by an arrow AD2 in FIG. The image carrier protecting agent 512 has a rectangular parallelepiped shape extending substantially parallel to the rotation axis of the brush roller 511, and is pressed against the brush roller 511 by a press applying member 513 from the side opposite to the photosensitive drum 550 side. ing. The pressing member 513 is a compression spring. The brush roller 511 rotates in the direction of the arrow AD2 to scrape off the protective agent from the image carrier protective agent 512, and the scraped protective agent is applied to the outer peripheral surface 551 of the photosensitive drum 550 after being cleaned by the cleaning unit 560. Apply.

  The protective agent leveling member 520 includes a blade 521 and a holding member 522. The blade 521 is disposed at a position downstream of the protective agent coating device 510 in the rotation direction of the photosensitive drum 550. The blade 521 is fixed to the case 501 via the holding member 522 so that the leading edge portion 521a contacts the outer peripheral surface 551 of the photosensitive drum 550 from the trailing direction with respect to the rotation direction. When the photosensitive drum 550 after application of the protective agent rotates in the direction of the arrow AD1 and the outer peripheral surface 551 on which the protective agent is applied passes directly below the front edge portion 521a, the blade 521 has a front edge portion 521a. Evenly protect the agent. As a result, a uniform protective agent layer is formed on the outer peripheral surface 551 of the photosensitive drum 550.

Further, as shown in FIG. 2, using a blade as the protective agent leveling member, the leading edge portion of the blade is brought into contact with the photoconductor from the counter direction, and the ridge line portion in contact with the photoconductor has an obtuse angle shape. A certain configuration is described (see Patent Document 7).
Here, FIG. 2 is a diagram showing another example of a conventional protective layer forming apparatus. The protective layer forming apparatus 600 is different from the protective layer forming apparatus 500 shown in FIG. 1 only in the protective agent leveling member 610. Therefore, in FIG. 2, the same components as those of the protective layer forming apparatus 500 shown in FIG. 1 are denoted by the same reference numerals as those in FIG. The duplicate description about is omitted.

  The protective agent leveling member 610 of FIG. 2 also has a blade 611 and a holding member 612. In FIG. 2, the blade 611 has a tip edge portion 611 a that is in contact with the outer peripheral surface 551 of the photosensitive drum 550 from the counter direction with respect to the rotation direction. Further, the leading edge portion 611 a of the blade 611 has an obtuse angled ridge portion, and the obtuse angled leading edge portion 611 a is in contact with the outer peripheral surface 551 of the photosensitive drum 550.

  Also in this other example, when the outer peripheral surface 511 of the photosensitive drum 550 to which the protective agent is applied passes immediately below the front edge portion 611a of the blade 611, the front edge portion 611a uniformly equalizes the protective agent. As a result, a uniform protective agent layer is formed on the outer peripheral surface 511 of the photosensitive drum 550.

As described above, all of the protective agent leveling members described in FIGS. 1 and 2 of Patent Documents 5, 6 and 7 apply pressure by causing the leading edge of the blade to bite into the surface of the photoreceptor. At this time, if the edge angle of the edge is an obtuse angle (90 degrees or more), the contact area with the surface of the photoreceptor when the edge bites into the surface of the photoreceptor is excessively increased, and the pressure per unit area [N / cm ² ] is reduced, and the coatability of the protective agent and the toner slipping prevention performance (cleaning performance) are deteriorated.

  Therefore, even when the amount of biting into the surface of the image carrier by the protective agent leveling member is small, by increasing the pressure per unit area, it is possible to improve the coatability of the image carrier protective agent and the toner slip-off preventing performance. It is desired to provide a protective layer forming apparatus that can be used.

  An object of the present invention is to solve the above-described problems and achieve the following objects. In other words, the present invention increases the pressure per unit area even when the amount of biting into the surface of the image carrier in the protective agent leveling member is small, thereby improving the coatability of the image carrier protective agent and preventing the toner from slipping through. An object of the present invention is to provide a protective layer forming apparatus that can be improved.

The protective layer forming apparatus of the present invention as means for solving the above problems is
An image carrier protective agent; and a protective agent supply member that supplies the image carrier protective agent to the surface of the image carrier;
A protective agent leveling member for leveling the image carrier protective agent supplied on the image carrier;
Having at least
The protective agent leveling member has an abutting portion having a triangular section with an apex angle D of 15 to 80 degrees, and the abutting portion abuts on the surface of the image carrier.

  According to the present invention, the conventional problems can be solved, the object can be achieved, and the contact pressure per unit area can be obtained even when the amount of biting into the surface of the image carrier in the protective agent leveling member is small. Thus, it is possible to provide a protective layer forming apparatus capable of improving the coating property of the image carrier protective agent and the toner slipping prevention performance.

It is the elements on larger scale which show an example of the conventional protective layer formation apparatus. It is the elements on larger scale which show another example of the conventional protective layer forming apparatus. It is the schematic which shows an example of the protective layer formation apparatus of this invention. FIG. 4 is a schematic view showing an example of the image forming apparatus of the present invention. FIG. 5 is a schematic view showing an example of the process cartridge of the present invention.

(Protective layer forming device)
The protective layer forming apparatus of the present invention includes an image carrier protective agent, a protective agent supply member, and a protective agent leveling member, and further includes other members as necessary.

  As a result of intensive studies in order to solve the above problems, the present inventors have found that the protective agent leveling member has a contact portion having a triangular cross section with an apex angle D of 15 degrees to 80 degrees, By abutting the surface of the image carrier at the top of the abutting portion, the contact area with the surface of the image carrier when the protective layer leveling member bites into the surface of the image carrier is reduced. Has a protective layer forming device that can improve the coating properties of the protective agent and the toner slip-off preventing performance by earning a pressure per unit area, and has a protective layer forming device that is stable and of high quality over a long period of time. It has been found that an image forming apparatus and a process cartridge capable of obtaining a clear image can be provided.

<Image carrier protecting agent>
The image carrier protecting agent of the present invention preferably contains a fatty acid metal salt and an inorganic lubricant, and more preferably contains other components as necessary.

<< Inorganic lubricant >>
The inorganic lubricant is a compound that cleaves and lubricates itself or causes internal slip.
The inorganic lubricant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, mica, boron nitride, molybdenum disulfide, tungsten disulfide, talc, kaolin, montmorillonite, calcium fluoride, graphite, etc. Is mentioned. These may be used individually by 1 type and may use 2 or more types together. Of these, boron nitride, mica, and talc are preferred, and hexagonal mesh surfaces with tightly assembled atoms overlap at wide intervals, and only the weak van der Waals forces connect the layers, making it easy to connect the layers. Boron nitride is particularly preferred because it is cleaved and lubricated.

The number average primary particle size of the inorganic lubricant is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.1 μm to 10 μm. In the preferable numerical range, it is possible to improve the cleaning property and prevent filming on the photoreceptor.
The number average primary particle size of the inorganic lubricant can be determined by, for example, using an observation image with a scanning electron microscope (SEM) (thermal F-SEM, manufactured by Zeiss, ULTRA55), image analysis / measurement software (Image-pro plus 4). 0.0j, manufactured by Media Cybernetics), and can be measured by taking the average of 10 of them.

  There is no restriction | limiting in particular as said inorganic lubricant, A commercial item can be used. Examples of the commercially available products include boron nitride (manufactured by Saint-Gobain, IDL, average primary particle size 0.6 μm), mica (manufactured by Topy Industries, Ltd., PDM-5B, average primary particle size 6 μm), and the like.

  There is no restriction | limiting in particular as content in the said image carrier protective agent of the said inorganic lubricant, Although it can select suitably according to the objective, 2 mass%-50 mass% are preferable, and 5 mass%-20 mass. % Is more preferable. If the content is less than 2% by mass, the amount of film formation decreases, contamination of the charging means may occur, and the cleaning property may decrease. If the content exceeds 50% by mass, the protection of the photoreceptor decreases. May end up.

<< Fatty acid metal salt >>
The fatty acid metal salt is not particularly limited and may be appropriately selected depending on the intended purpose. For example, barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, stearin Strontium acid, calcium stearate, cadmium stearate, magnesium stearate, zinc stearate, zinc oleate, magnesium oleate, iron oleate, cobalt oleate, copper oleate, lead oleate, manganese oleate, zinc palmitate, Cobalt palmitate, lead palmitate, magnesium palmitate, aluminum palmitate, calcium palmitate, lead caprylate, lead caprate, zinc linolenate, cobalt linolenate, calcium linolenate, Lumpur zinc, cadmium ricinoleate, zinc laurate, cobalt laurate, lauric lead, magnesium laurate, and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, zinc stearate, calcium stearate, and zinc laurate are preferable, zinc stearate because it is a very stable substance that is excellent in cleaning properties and photoconductor protection, inexpensive, and hydrophobic. Is particularly preferred.

The mass ratio between the fatty acid metal salt and the inorganic lubricant (fatty acid metal salt / inorganic lubricant) is not particularly limited and may be appropriately selected depending on the intended purpose, but is 98/2 to 85/15. Preferably, 95/5 to 90/10 is more preferable. When the mass ratio of the fatty acid metal salt is larger than the range of the mass ratio (fatty acid metal salt / inorganic lubricant), the amount of film formation decreases, the contamination of the charging means may occur, and the cleaning property may be deteriorated. On the other hand, when the ratio of the inorganic lubricant is larger than the range of the mass ratio (fatty acid metal salt / inorganic lubricant), the protection of the photoreceptor may be lowered.
When the mass ratio (fatty acid metal salt / inorganic lubricant) is within a preferable numerical range, the film forming property is improved while the content of expensive boron nitride is reduced, the charging means is not contaminated, the cleaning property and the photoconductor. There is an advantage that the protective property of is improved.

<< Other ingredients >>
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, resin fine particle, surfactant, a dispersing agent etc. are mentioned.

The method for molding the image carrier protective agent into a fixed shape, for example, a prismatic or cylindrical shape, is not particularly limited, and a known method can be used as a method for molding a solid substance, for example, Examples thereof include compression molding, melt molding, powder molding, cold isostatic pressing (CIP), and hot isostatic pressing (HIP). Among these, the compression molding method is particularly preferable from the viewpoint of easy cutting of the molded body.
In the compression molding method, a mixture of a fatty acid metal salt and an inorganic lubricant is placed in a mold having a predetermined size, and then compression molded at a predetermined pressure and time. After cooling, the solid is removed from the mold. A molded body can be obtained. Thereafter, the shape of the image carrier protecting agent may be adjusted by cutting or the like.

There is no restriction | limiting in particular as said formwork, Although it can select suitably according to the objective, Metal formwork, such as steel materials, stainless steel, and aluminum, from the good heat conductivity and the good dimensional accuracy is preferable. The inner wall surface of the mold is preferably coated with a release agent such as a fluororesin or a silicone resin in order to improve the releasability.
The produced block-shaped image carrier protecting agent is used by being bonded to a base material such as a metal, an alloy, or plastic with an adhesive or the like.

<Protective agent supply member>
The protective agent supply member is a member that supplies the image carrier protective agent to the surface of the image carrier, and examples thereof include a brush roller, a rubber roller, and a urethane roller. Among these, a brush roller is preferable.

As the brush-like member in the brush roller, it is preferable that the brush fiber has flexibility in order to suppress mechanical stress on the surface of the image carrier. There is no restriction | limiting in particular as a material of the said flexible brush fiber, According to the objective, it can select suitably, For example, polyolefin resin (for example, polyethylene, polypropylene, etc.); polyvinyl resin or polyvinylidene resin (For example, polystyrene, acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polyvinyl ketone, etc.); vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer Styrene-butadiene resin; fluororesin (eg, polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, etc.); polyester; nylon; acrylic; rayon; Polyurethane; polycarbonate; phenolic resins; amino resins (eg, urea - formaldehyde resins, melamine resins, benzoguanamine resins, urea resins, polyamide resins, etc.), and the like.
In order to adjust the degree of bending, the resin includes, for example, diene rubber, styrene-butadiene rubber (SBR), ethylene propylene rubber, isoprene rubber, nitrile rubber, urethane rubber, silicone rubber, hydrin rubber, norbornene rubber, and the like. Can be used in combination.

The support for the protective agent supply member includes a fixed mold and a rotatable roll. Examples of the roll-shaped supply member include a roll brush obtained by winding a tape having brush fibers piled around a metal core bar in a spiral shape. The brush fiber has a fiber diameter of about 10 μm to 500 μm, the length of the brush fiber is 1 mm to 15 mm, and the brush density is 10,000 to 300,000 per square inch (1.5 × 10 ⁷ to 4 per square meter). .5 × 10 ⁸ ) is preferable.

  The protective agent supply member is preferably made of a material having a high brush density in terms of supply uniformity and supply stability, and a single fiber is produced from several to hundreds of fine fibers. It is also preferable. For example, bundling 50 fine fibers of 6.7 decitex (6 denier), such as 333 decitex = 6.7 decitex × 50 filament (300 denier = 6 denier × 50 filament), and implanting as one fiber Is also possible.

Moreover, you may provide a coating layer in the said brush surface for the purpose of stabilizing the surface shape of a brush, environmental stability, etc. as needed. As the component constituting the coating layer, it is preferable to use a coating layer component that can be deformed according to the bending of the brush fiber.
The coating layer component is not particularly limited as long as it is a material that can maintain flexibility, and can be appropriately selected according to the purpose. Examples thereof include polyethylene, polypropylene, chlorinated polyethylene, and chlorosulfonated polyethylene. Polyolefin-based resins; polystyrene, acrylic (for example, polymethyl methacrylate), polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polybiliketones, and other polyvinyl or polyvinylidene resins; Vinyl acetate copolymer; silicone resin composed of organosiloxane bond or modified product thereof (for example, modified product by alkyd resin, polyester resin, epoxy resin, polyurethane, etc.); Fluorine resins such as cycloalkyl ether, polyfluorovinyl, polyfluorovinylidene, and polychlorotrifluoroethylene; polyamides; polyesters; polyurethanes; polycarbonates; amino resins such as urea-formaldehyde resins; epoxy resins or composite resins thereof Can be mentioned.

<Protective agent leveling member>
The protective agent leveling member is a member for leveling the image carrier protective agent supplied to the image carrier, and examples thereof include a member composed of the contact portion and the holding member.

The protective agent leveling member has an abutting portion having a triangular section with an apex angle D of 15 to 80 degrees, and the abutting portion abuts on the surface of the image carrier. By making the cross-sectional shape of the protective agent leveling member triangular, the contact area with the image carrier when the contact portion of the protective agent leveling member bites into the surface of the image carrier can be reduced. By increasing the pressure per unit area, it is possible to provide a protective layer forming apparatus, an image forming apparatus, and a process cartridge that can improve cleaning properties and can stably obtain a high-quality image over a long period of time.
The protective agent leveling member has an apex angle D of 15 to 80 degrees, preferably 40 to 60 degrees. When the apex angle D is less than 15 degrees, the contact portion between the protective agent leveling member and the image carrier is too thin, and the pressure per unit area is too strong. And wear of the blade over time tends to progress, and toner slipping may occur. On the other hand, when the apex angle D exceeds 80 degrees, the contact area with the image carrier when the contact portion of the protective agent leveling member is bitten into the image carrier is excessively increased. Since the pressure of the toner decreases, the coatability of the protective agent may be deteriorated or the toner may slip through.

The amount of biting into the surface of the image carrier at the contact portion of the protective agent leveling member is preferably 0.1 mm to 1.5 mm, and more preferably 0.2 mm to 1.0 mm. If the biting amount is less than 0.05 mm, the pressure applied to the image carrier is too weak, and toner slipping may occur. On the other hand, if the amount of biting exceeds 1.5 mm, the contact area with the image carrier increases excessively, and the pressure per unit area decreases. I sometimes get up.
For example, the amount of biting into the surface of the image carrier at the contact portion of the protective agent leveling member can be determined using a dedicated instrument (custom product). In a state where the image carrier is not attached to the shaft shaft of the image carrier, the dedicated instrument (a circular instrument having 30 blades of different lengths; the length of the blade corresponds to the amount of biting of the contact portion ), The length of the blade that contacts the tip of the contact portion of the protective agent leveling member is determined, and the amount of biting can be measured from the length of the blade at that time.

There is no restriction | limiting in particular as a material of the said contact part, According to the objective, it can select suitably, For example, urethane rubber, hydrin rubber, silicone rubber, fluororubber etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, urethane rubber is preferable.
The contact portion can be produced, for example, by cutting urethane rubber into a desired shape, or by pouring liquid urethane rubber into a casting mold and curing it. In this case, the apex angle D of the abutting portion can be adjusted by changing the angle at which the urethane rubber is cut or by changing the shape of the casting by pouring liquid urethane rubber into the casting and curing it. it can.
The contact portion may be coated or impregnated with a low friction coefficient material at the contact portion with the image carrier. Further, in order to adjust the hardness of the blade, a filler such as an organic filler or an inorganic filler may be dispersed.

There is no restriction | limiting in particular as the height of the said contact part, Although it cannot define uniquely by balance with the force added by a press, 0.5 mm-10 mm are preferable and 3 mm-8 mm are more preferable.
There is no restriction | limiting in particular as the hardness of the said contact part, Although it can select suitably according to the objective, 40 to 80 degree | times is preferable.
The hardness is Shore A hardness and can be measured at 25 ° C. by durometer type A in accordance with JIS K6253: 2001.
The abutting portion is fixed to the holding member by any method such as adhesion or fusion so that it can be pressed against the surface of the image carrier.
As the holding member, for example, an elastic metal blade such as a spring plate is used.
There is no restriction | limiting in particular as thickness of the said elastic metal braid | blade, Although it can select suitably according to the objective, 0.05 mm-3 mm are preferable and 0.1 mm-1 mm are more preferable.
In the elastic metal blade, in order to suppress twisting of the blade, a process such as bending may be performed in a direction substantially parallel to the support shaft after the attachment.
The length of the holding member is not particularly limited and cannot be uniquely defined in consideration of the force applied by pressing, but is preferably 1 mm to 15 mm, and more preferably 2 mm to 10 mm.

<Other members>
There is no restriction | limiting in particular as said other member, According to the objective, it can select suitably, For example, a pressing force provision member etc. are mentioned.

-Pressure applying member-
The pressing force applying member is a member that presses the image carrier protecting agent and presses it against the protecting agent supply member.
Examples of the pressing force applying member include a spring such as a leaf spring and a compression spring.

  Here, the protective layer forming apparatus of the present invention will be described with reference to the drawings. FIG. 3 is a schematic cross-sectional view showing an example of the protective layer forming apparatus of the present invention. FIG. 3 shows the protective layer forming apparatus 70 together with the photosensitive drum 3 and the cleaning means 6.

  The protective layer forming apparatus 70 rubs the protective agent supply member 7a for supplying a protective agent to the outer peripheral surface of the photosensitive drum 3 and the outer peripheral surface of the photosensitive drum 3 coated with the protective agent, and smoothes the protective agent. And a protective agent leveling member 8. The protective agent supply member 7a corresponds to an example of the protective agent supply member according to the present invention, and the protective agent leveling member 8 corresponds to an example of the protective agent leveling member according to the present invention. The protective agent supply member 7a, the image carrier protective agent 7b, and the pressing member 7c may be collectively referred to as a protective agent application device 7.

  The brush roller as the protective agent supply member 7 a is accommodated in the case 6 c of the protective layer forming apparatus 70 so as to be rotatable around a rotation axis substantially parallel to the rotation axis of the photosensitive drum 3. The brush roller as the protective agent supply member 7a is disposed on the downstream side of the cleaning unit 6 with respect to the rotation direction of the photosensitive drum 3 (the direction of the arrow D1). Then, the brush roller as the protective agent supply member 7a is rotationally driven in a rotation direction indicated by an arrow D2 by a drive source (not shown), and slides on the outer peripheral surface of the photosensitive drum 3 after the adhered material is removed by the cleaning means 6. Rub. The image carrier protecting agent 7b has a rectangular parallelepiped shape extending substantially in parallel with the rotating shaft of the brush roller as the protecting agent supply member 7a, and the brush roller serving as the protecting agent supply member 7a is connected to the photosensitive drum 3 side. It is pressed by the pressing member 7c from the opposite side. The pressing member 7c is preferably a member that presses the image carrier protecting agent 7b with a spring such as a plate spring or a compression spring, and a compression spring is preferable.

  The image carrier protective agent 7b is scraped off and consumed by a brush roller as a rotating protective agent supply member 7a, and its thickness decreases with time. However, since the pressure is applied by the pressing member 7c, the image carrier protective agent 7b is always used as a brush roller. It is in contact. The brush roller applies and supplies the protective agent scraped off while rotating to the outer peripheral surface of the photosensitive drum 3. The protective agent scraped off from the image carrier protective agent 7b corresponds to an example of the protective agent referred to in the present invention. The protective agent coating device 7 has a driving means (not shown) that swings the brush roller or the image carrier protective agent 7b as the protective agent supply member 7a in a longitudinal direction substantially parallel to the rotation axis of the brush roller. Also good. By swinging the brush roller or the image carrier protecting agent 7b as the protecting agent supply member 7a, the coating unevenness is reduced, and the protecting agent can be applied more uniformly. The rotation direction of the brush roller as the protective agent supply member 7a is preferably forward with respect to the rotation direction of the photosensitive drum 3, as indicated by an arrow D2, but may be rotated in the reverse direction.

  The protective agent forming the image carrier protective agent 7b contains a fatty acid metal salt and an inorganic lubricant, and protects the outer peripheral surface of the photosensitive drum 3 and imparts lubricity to the outer peripheral surface.

  The protective agent leveling member 8 has a contact portion 8a and a holding member 8b. As shown in FIG. 3, the abutting portion 8a abuts from the counter direction with respect to the rotation direction of the photosensitive drum 3 (arrow D1) by the holding member 8b fixed to the case 6c of the protective layer forming apparatus 70, and the protective agent It is supported at a position downstream of the brush roller as the supply member 7a. The contact portion 8a has a triangular cross section with an apex angle D of 15 degrees to 80 degrees. The protective agent applied by the protective agent applying device 7 is rubbed and leveled by the contact portion 8a that is in contact with the outer peripheral surface of the photosensitive drum, and a protective agent layer is formed on the outer peripheral surface of the photosensitive drum. .

  According to the protective agent leveling member 8 in the protective layer forming apparatus 70 of the present embodiment described above, the contact portion having a triangular cross section having an apex angle D of 15 degrees to 80 degrees, Abuts against the surface of the image carrier. By making the cross-sectional shape of the protective agent leveling member triangular, the contact area with the image carrier when the contact portion of the protective agent leveling member bites into the surface of the image carrier can be reduced. By increasing the pressure per unit area, it is possible to provide a protective layer forming apparatus capable of improving the cleaning property and obtaining a high-quality image stably over a long period of time.

(Image forming method and image forming apparatus)
The image forming method used in the present invention includes at least an electrostatic latent image forming step, a developing step, a transfer step, and a protective layer forming step, preferably including a cleaning step and a fixing step, and further if necessary. Other processes selected as appropriate, for example, a static elimination process, a recycling process, a control process, and the like are included.
The image forming apparatus of the present invention includes at least an image carrier, an electrostatic latent image forming unit, a developing unit, a transfer unit, and a protective layer forming unit, and preferably includes a cleaning unit and a fixing unit. In addition, other means appropriately selected as necessary, for example, static elimination means, recycling means, control means and the like are provided.

  The image forming method of the present invention can be preferably carried out by the image forming apparatus of the present invention, the electrostatic latent image forming step can be performed by the electrostatic latent image forming means, and the developing step is the developing The transfer step can be performed by the transfer unit, the protective layer forming step can be performed by the protective layer forming unit, and the cleaning step can be performed by the cleaning unit, The fixing step can be performed by the fixing unit, and the other steps can be performed by the other unit.

<Electrostatic latent image forming step and electrostatic latent image forming means>
The electrostatic latent image forming step is a step of forming an electrostatic latent image on the image carrier, and is performed by an electrostatic latent image forming unit.

-Image carrier-
The image carrier (hereinafter sometimes referred to as “electrophotographic photoreceptor” or “photoreceptor”) is not particularly limited in terms of its material, shape, structure, size, etc., and is appropriately selected from known ones. The shape is preferably a drum shape, and examples of the material include inorganic photoconductors such as amorphous silicon and selenium, and organic photoconductors such as polysilane and phthalopolymethine.

  The image carrier has a conductive support and at least a photosensitive layer on the conductive support, and further has other layers as necessary.

As the photosensitive layer, a single layer type in which a charge generation material and a charge transport material are mixed, a forward layer type in which a charge transport layer is provided on the charge generation layer, or a charge generation layer is provided on the charge transport layer. There is a reverse layer type. In order to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property, etc. of the photoreceptor, an outermost surface layer can be provided on the photosensitive layer. An undercoat layer may be provided between the photosensitive layer and the conductive support.
In addition, an appropriate amount of a plasticizer, an antioxidant, a leveling agent, or the like can be added to each layer as necessary.

The conductive support is not particularly limited as long as it has a volume resistance of 1.0 × 10 ¹⁰ Ω · cm or less, and can be appropriately selected according to the purpose. Metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, and metal oxides such as tin oxide and indium oxide coated with film or cylindrical plastic or paper by vapor deposition or sputtering, Alternatively, a plate made of aluminum, aluminum alloy, nickel, stainless steel or the like, and a tube subjected to surface treatment such as cutting, super-finishing, polishing, etc. after forming them into a drum shape by a method such as extrusion or drawing can be used. .

  There is no restriction | limiting in particular as said drum-shaped support body, Although it can select suitably according to the objective, 20 mm-150 mm in diameter are preferable, 24 mm-100 mm are more preferable, and 28 mm-70 mm are still more preferable. When the diameter of the drum-shaped support is less than 20 mm, it may be physically difficult to arrange the charging, exposure, development, transfer, and cleaning steps around the drum, and when the diameter exceeds 150 mm. The image forming apparatus may become large. In particular, when the image forming apparatus is a tandem type, since it is necessary to mount a plurality of photoconductors, the diameter is preferably 70 mm or less, and more preferably 60 mm or less. Further, an endless nickel belt or an endless stainless steel belt as disclosed in JP-A-52-36016 can also be used as the conductive support.

The undercoat layer of the photoreceptor may be composed of a single layer or a plurality of layers. For example, (1) the resin is the main component, and (2) the white pigment and the resin are the main components. And (3) a metal oxide film obtained by chemically or electrochemically oxidizing the surface of a conductive substrate. Among these, those containing a white pigment and a resin as main components are preferable.
Examples of the white pigment include metal oxides such as titanium oxide, aluminum oxide, zirconium oxide, and zinc oxide. Among these, titanium oxide is particularly preferable because it is excellent in preventing injection of charges from the conductive support.
Examples of the resin include thermoplastic resins such as polyamide, polyvinyl alcohol, casein, and methyl cellulose; thermosetting resins such as acrylic, phenol, melamine, alkyd, unsaturated polyester, and epoxy. These may be used individually by 1 type and may use 2 or more types together.
The thickness of the undercoat layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.1 μm to 10 μm, and more preferably 1 μm to 5 μm.

  Examples of the charge generation material in the photosensitive layer include monoazo pigments, bisazo pigments, trisazo pigments, tetrakisazo pigments and other azo pigments, triarylmethane dyes, thiazine dyes, oxazine dyes, xanthene dyes, Cyanine dyes, styryl dyes, pyrylium dyes, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, bisbenzimidazole pigments, indanthrone pigments, squarylium pigments, phthalocyanine pigments, etc. Organic pigments or dyes; selenium, selenium-arsenic, selenium-tellurium, cadmium sulfide, zinc oxide, titanium oxide, amorphous silicon, and other inorganic materials. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the charge transport material in the photosensitive layer include anthracene derivatives, pyrene derivatives, carbazole derivatives, tetrazole derivatives, metallocene derivatives, phenothiazine derivatives, pyrazoline compounds, hydrazone compounds, styryl compounds, styryl hydrazone compounds, enamine compounds, butadiene compounds, distyryl. Examples thereof include compounds, oxazole compounds, oxadiazole compounds, thiazole compounds, imidazole compounds, triphenylamine derivatives, phenylenediamine derivatives, aminostilbene derivatives, and triphenylmethane derivatives. These may be used individually by 1 type and may use 2 or more types together.

  As the binder resin used to form the photosensitive layer, it is electrically insulating and may be a known thermoplastic resin, thermosetting resin, photocurable resin, photoconductive resin, or the like. it can. Examples of the binder resin include polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, ethylene-vinyl acetate copolymer, polyvinyl butyral, Polyvinyl acetal, polyester, phenoxy resin, (meth) acrylic resin, polystyrene, polycarbonate, polyarylate, polysulfone, polyethersulfone, ABS resin and other thermoplastic resins, phenol resin, epoxy resin, urethane resin, melamine resin, isocyanate Examples thereof include thermosetting resins such as resins, alkyd resins, silicone resins, and thermosetting acrylic resins, polyvinyl carbazole, polyvinyl anthracene, and polyvinyl pyrene. These may be used individually by 1 type and may use 2 or more types together.

The outermost surface layer of the photoreceptor is provided to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property, and the like of the photoreceptor.
As the outermost surface layer, a polymer having a mechanical strength higher than that of the photosensitive layer and a material in which an inorganic filler is dispersed in the polymer are suitable. The resin used for the outermost surface layer may be either a thermoplastic resin or a thermosetting resin, but the thermosetting resin has high mechanical strength and suppresses wear due to friction with the cleaning blade. This is particularly preferable because of its extremely high capacity. If the surface layer is thin, there is no problem even if it does not have the charge transport capability, but if the surface layer without the charge transport capability is formed thick, the sensitivity of the photoreceptor decreases, the potential increases after exposure, and the residual layer Since the potential rise is likely to occur, it is preferable to include the above-described charge transport material in the surface layer or to use a polymer having charge transport ability as the polymer used in the surface layer.

  Since the mechanical strength of the photosensitive layer and the outermost surface layer is generally greatly different, the outermost surface layer is worn away due to friction with the cleaning blade, and when the outermost layer disappears, the photosensitive layer is immediately worn away. When providing a layer, it is preferable that the outermost surface layer has a sufficient thickness. The thickness of the outermost surface layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.1 μm to 12 μm, more preferably 1 μm to 10 μm, and particularly preferably 2 μm to 8 μm. When the thickness is less than 0.1 μm, it is too thin and is likely to be partially lost due to friction with the cleaning blade, and wear of the photosensitive layer may proceed from the lost portion. Decrease in sensitivity, increase in potential after exposure, and increase in residual potential are likely to occur. Particularly when a polymer having charge transport ability is used, the cost of the polymer having charge transport ability may be increased.

  The resin used for the outermost surface layer is not particularly limited, and is preferably one that is transparent to writing light at the time of image formation and excellent in insulation, mechanical strength, and adhesiveness. For example, ABS resin, ACS Resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene, polyethylene Terephthalate, polyimide, acrylic resin, polymethyl bentene, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polyvinyl chloride , And epoxy resins. These polymers may be thermoplastic resins, but in order to increase the mechanical strength of the polymers, they are crosslinked with a crosslinking agent having a polyfunctional acryloyl group, carboxyl group, hydroxyl group, amino group, etc. By using a functional resin, the mechanical strength of the outermost surface layer is increased, and wear due to friction with the cleaning blade can be greatly reduced.

  The outermost surface layer preferably has a charge transporting capability. In order to provide the outermost surface layer with a charge transporting capability, the polymer used for the outermost surface layer and the above-described charge transporting material are mixed and used. A method using a polymer having a charge transporting capability for the outermost surface layer is conceivable, and the latter method is preferable because a high-sensitivity photoreceptor with little increase in potential after exposure and little increase in residual potential can be obtained.

  The outermost surface layer preferably contains metal fine particles, metal oxide fine particles, and other fine particles in order to increase the mechanical strength of the outermost surface layer. Examples of the metal oxide include titanium oxide, tin oxide, potassium titanate, titanium nitride, zinc oxide, indium oxide, and antimony oxide. Examples of the other fine particles include fluorine resins such as polytetrafluoroethylene, silicone resins, or those obtained by dispersing inorganic materials in these resins for the purpose of improving wear resistance.

  Next, the formation of the electrostatic latent image can be performed, for example, by charging the surface of the image carrier and then performing imagewise exposure, and can be performed by the electrostatic latent image forming unit. The electrostatic latent image forming unit includes, for example, at least a charger for charging the surface of the image carrier and an exposure unit for exposing the surface of the image carrier imagewise.

The charging can be performed, for example, by applying a voltage to the surface of the image carrier using the charger.
The charger is not particularly limited and may be appropriately selected depending on the purpose. For example, a known contact charging device including a conductive or semiconductive roll, brush, film, rubber blade, etc. And non-contact chargers utilizing corona discharge such as corotrons and corotrons.
The charger preferably has voltage applying means for applying a voltage having an AC component.

The exposure can be performed, for example, by exposing the surface of the image carrier imagewise using the exposure device.
The exposure device is not particularly limited as long as it can perform image-like exposure on the surface of the image carrier charged by the charger, and can be appropriately selected according to the purpose. Examples include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system.
In the present invention, an optical back side system in which imagewise exposure is performed from the back side of the image carrier may be adopted.

<Development process and development means>
The developing step is a step of developing the electrostatic latent image using a toner or a developer to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using the toner or the developer, and can be performed by the developing unit.
The developing means is not particularly limited as long as it can be developed using, for example, the toner or the developer, and can be appropriately selected from known ones. For example, the toner or developer is stored. Preferred examples include those having at least a developing unit capable of bringing the toner or developer into contact or non-contact with the electrostatic latent image.

<< Toner >>
The toner is not particularly limited and may be appropriately selected depending on the intended purpose.For example, a polyester prepolymer having a functional group containing a nitrogen atom, a compound that extends or crosslinks with the prepolymer, a polyester, a colorant, Examples thereof include a toner prepared by crosslinking or extending a toner composition containing a release agent in an aqueous medium in the presence of resin fine particles. This toner can reduce the hot offset by curing the toner surface, and can prevent the toner from appearing on the image due to contamination of the fixing device.

Examples of the polyester prepolymer having a functional group containing a nitrogen atom include a polyester prepolymer having an isocyanate group, and examples of the compound that extends or crosslinks with the prepolymer include amines.
Examples of the polyester prepolymer having an isocyanate group include a product obtained by further reacting a polyester having an active hydrogen group with a polyisocyanate, which is a condensate of a polyol and a polycarboxylic acid. Examples of the active hydrogen group possessed by the polyester include a hydroxyl group (alcoholic hydroxyl group and phenolic hydroxyl group), an amino group, a carboxyl group, and a mercapto group. Among these, alcoholic hydroxyl groups are particularly preferable.

  There is no restriction | limiting in particular as said polyol, According to the objective, it can select suitably, For example, diol, a trivalent or more polyol, etc. are mentioned. Among these, a diol alone or a mixture of a diol and a small amount of a trivalent or higher polyol is preferable.

  There is no restriction | limiting in particular as said polycarboxylic acid, According to the objective, it can select suitably, For example, dicarboxylic acid, trivalent or more polycarboxylic acid, etc. are mentioned. Among these, dicarboxylic acid alone or a mixture of dicarboxylic acid and a small amount of trivalent or higher polycarboxylic acid is preferable.

  The ratio of the polyol and the polycarboxylic acid is not particularly limited and may be appropriately selected depending on the purpose. The equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH] is 2 / 1-1 / 1 is preferable, 1.5 / 1 to 1/1 is more preferable, and 1.3 / 1 to 1.02 / 1 is still more preferable.

  Examples of the polyisocyanate include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); Diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates; Or something blocked. These may be used individually by 1 type and may use 2 or more types together.

  The ratio of the polyisocyanate is not particularly limited and may be appropriately selected depending on the intended purpose. The equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group is not limited. Is preferably 5/1 to 1/1, more preferably 4/1 to 1.2 / 1, and still more preferably 2.5 / 1 to 1.5 / 1. When the [NCO] / [OH] exceeds 5, the low-temperature fixability may be deteriorated. When the molar ratio of [NCO] is less than 1, the urea content in the modified polyester is lowered, and hot resistance Offset property deteriorates.

  Examples of the amines include diamines, trivalent or higher polyamines, amino alcohols, amino mercaptans, amino acids, and those obtained by blocking these amino groups. Among these amines, preferred are diamine and a mixture of a diamine and a small amount of a triamine or higher polyamine.

  Furthermore, if necessary, the molecular weight of the urea-modified polyester can be adjusted using an elongation terminator. Examples of the elongation terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), or those obtained by blocking them (ketimine compounds).

  In addition, the image forming method and the image forming apparatus can be applied not only to the polymerization toner having a configuration suitable for obtaining a high-quality image as described above, but also to an irregular shaped toner by a pulverization method, Even in this case, the life of the apparatus can be greatly extended. As a material constituting such a pulverized toner, those usually used as an electrophotographic toner can be applied without particular limitation.

  The developing unit may be a dry developing type, a wet developing type, a single color developing unit, or a multi-color developing unit. For example, a toner having a stirrer for charging the toner or the developer by frictional stirring and a rotatable magnet roller is preferable.

In the developing device, for example, the toner and the carrier are mixed and agitated, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. . Since the magnet roller is disposed in the vicinity of the image carrier, a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is electrically attracted to the image carrier. Move to the surface. As a result, the electrostatic latent image is developed with the toner to form a visible image with the toner on the surface of the image carrier.
The developer accommodated in the developing device is a developer containing the toner, but the developer may be a one-component developer or a two-component developer.

<Transfer process and transfer means>
The transfer step is a step of transferring the visible image onto a recording medium. After the primary transfer of the visible image onto the intermediate transfer member using an intermediate transfer member, the visible image is transferred onto the recording medium. A primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer body using two or more colors, preferably full color toner as the toner, and a composite transfer image; A mode including a secondary transfer step of transferring the transfer image onto the recording medium is more preferable.
The transfer can be performed, for example, by charging the image carrier with the visible image using a transfer charger, and can be performed by the transfer unit. The transfer means includes a primary transfer means for transferring a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer means for transferring the composite transfer image onto a recording medium. Embodiments are preferred.
The intermediate transfer member is not particularly limited and may be appropriately selected from known transfer members according to the purpose. For example, a transfer belt and the like are preferable.

  The image carrier is an intermediate transfer member used for image formation by a so-called intermediate transfer method in which a toner image formed on a photosensitive member is primarily transferred to perform color superposition and further transferred to a recording medium. It may be.

<< Intermediate transfer body >>
As the intermediate transfer member, a material having a volume resistivity of 1.0 × 10 ⁵ Ω · cm to 1.0 × 10 ¹¹ Ω · cm is preferable. When the volume resistivity is less than 1.0 × 10 ⁵ Ω · cm, so-called transfer dust is generated in which the toner image is disturbed with discharge when the toner image is transferred from the photosensitive member to the intermediate transfer member. In the case where it exceeds 1.0 × 10 ¹¹ Ω · cm, after transferring the toner image from the intermediate transfer member to a recording medium such as paper, the counter charge of the toner image remains on the intermediate transfer member, It may appear as an afterimage on the next image.

As the intermediate transfer member, for example, a metal oxide such as tin oxide or indium oxide, a conductive particle such as carbon black, or a conductive polymer, alone or in combination, kneaded with a thermoplastic resin, and then an extrusion molded belt A cylindrical or cylindrical plastic can be used. In addition to this, the above-mentioned conductive particles and conductive polymer are added to a resin solution containing a thermally crosslinkable monomer or oligomer, if necessary, and subjected to centrifugal molding while heating to obtain an intermediate transfer member on an endless belt. You can also
When the surface layer is provided on the intermediate transfer member, the resistance adjustment is performed by appropriately using a conductive substance in the composition excluding the charge transporting material among the surface layer materials used for the surface layer of the photosensitive member. Can be used.

The transfer unit (the primary transfer unit and the secondary transfer unit) preferably includes at least a transfer unit that peels and charges the visible image formed on the image carrier to the recording medium side. . There may be one transfer means or two or more transfer means. Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is not particularly limited and can be appropriately selected from known recording media (recording paper).

<Protective layer forming step and protective layer forming means>
The protective layer forming step is a step of forming a protective layer by applying an image carrier protective agent to the surface of the image carrier after transfer.
As the protective layer forming means, the protective layer forming apparatus of the present invention described above is used.

<Fixing process and fixing means>
The fixing step is a step of fixing the visible image transferred to the recording medium using the fixing unit, and may be performed each time the toner of each color is transferred to the recording medium, or may be applied to the toner of each color. On the other hand, it may be carried out simultaneously at the same time in a state of being laminated.
The fixing unit is not particularly limited and may be appropriately selected depending on the intended purpose, but a known heating and pressing unit is preferable. Examples of the heating and pressing means include a combination of a heating roller and a pressure roller, a combination of a heating roller, a pressure roller, and an endless belt.
The heating in the heating and pressing means is usually preferably 80 ° C to 200 ° C.
In the present invention, for example, a known optical fixing device may be used together with or in place of the fixing step and the fixing unit depending on the purpose.

<Cleaning process and cleaning means>
The cleaning step is a step of removing the toner remaining on the image carrier and can be suitably performed by a cleaning unit.
The cleaning unit is preferably provided downstream of the transfer unit and upstream of the protective layer forming unit.
The cleaning means is not particularly limited, and may be selected from known cleaners as long as it can remove the electrophotographic toner remaining on the image carrier. For example, a magnetic brush cleaner, Suitable examples include electrostatic brush cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, web cleaners, and the like.

<Other processes and other means>
As said other process, a static elimination process, a recycle process, a control process etc. are mentioned, for example.
Examples of the other means include a static elimination means, a recycling means, and a control means.

-Static elimination process and static elimination means-
The neutralization step is a step of performing neutralization by applying a neutralization bias to the image carrier, and can be suitably performed by a neutralization unit.
The neutralization means is not particularly limited and may be appropriately selected from known neutralizers as long as it can apply a neutralization bias to the image carrier. It is done.

-Recycling process and recycling means-
The recycling step is a step of recycling the toner removed by the cleaning step to the developing unit, and can be suitably performed by the recycling unit.
There is no restriction | limiting in particular as said recycling means, A well-known conveyance means etc. are mentioned.

-Control process and control means-
The control step is a step of controlling each of the steps, and can be suitably performed by a control unit.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as sequencers and computers.

(Process cartridge)
The process cartridge of the present invention comprises at least an image carrier and the protective layer forming means of the present invention, and further, charging means, exposure means, developing means, transfer means, cleaning means, charge eliminating means as necessary. It has other means such as.
The process cartridge can be detachably provided in various electrophotographic apparatuses, and is preferably provided detachably in the image forming apparatus of the present invention described above.

  Here, FIG. 4 is a schematic configuration diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 100 includes a printer unit 1, a paper feed unit 10, and a document conveyance reading unit 20. The document conveying / reading unit 20 includes a scanner 21 serving as a document reading device fixed on the printer unit 1 and an ADF 22 serving as a document conveying device supported by the scanner 21.

  The printer unit 1 includes four process cartridges 2Y, 2M, 2C, and 2K for forming yellow (Y), magenta (M), cyan (C), and black (K) toner images. The process cartridges 2Y, 2M, 2C, and 2K for the respective colors are detachably attached to the casing 100a of the image forming apparatus 100. Each of these four process cartridges 2Y, 2M, 2C, and 2K corresponds to an example of a process cartridge according to the present invention.

  The process cartridges 2Y, 2M, 2C, and 2K for the respective colors have photosensitive drums 3Y, 3M, 3C, and 3K arranged at a predetermined pitch above the intermediate transfer belt 41 that is rotationally driven in the direction of the arrow in FIG. doing. A toner image based on Y, M, C, and K image information is formed on the photosensitive drums 3Y, 3M, 3C, and 3K for each color as described later.

  Above the process cartridges 2Y, 2M, 2C, and 2K, an optical writing unit 30 serving as a latent image forming unit is provided. The optical writing unit 30 includes a laser diode, a polygon mirror, various lenses, and the like. The optical writing unit 30 drives the laser diode based on image information read by the scanner 21 or image information sent from an external personal computer. The optical writing unit 30 optically scans the photosensitive drums 3Y, 3M, 3C, and 3K of the process cartridges 2Y, 2M, 2C, and 2K. Specifically, the optical writing unit 30 deflects the laser light L in the direction of the rotation axis of the photoconductors with respect to the photoconductor drums 3Y, 3M, 3C, and 3K that are driven to rotate counterclockwise in FIG. The light scanning process is performed by irradiation. Thereby, electrostatic latent images based on image information of each color of Y, M, C, and K are formed on the photosensitive drums 3Y, 3M, 3C, and 3K.

  Below the process cartridges 2Y, 2M, 2C, and 2K, an intermediate transfer unit 40 as transfer means is disposed. The intermediate transfer unit 40 includes an intermediate transfer belt 41 that is stretched and rotated by a plurality of rollers. The intermediate transfer belt 41 is an endless belt made of a heat-resistant material such as polyimide or polyamide and made of a base adjusted to a medium resistance. Then, the intermediate transfer unit 40 forms a primary transfer nip by sandwiching the intermediate transfer belt between the photosensitive drums 3Y, 3M, 3C, and 3K and primary transfer rollers 42Y, 42M, 42C, and 42K to which a predetermined voltage is applied. To do. Further, the intermediate transfer unit 40 forms a secondary transfer nip by sandwiching the intermediate transfer belt 41 between the secondary transfer backup roller 43 and the secondary transfer roller 44 to which a predetermined voltage is applied. Further, the intermediate transfer unit 40 includes a cleaning device 45 that removes transfer residual toner remaining on the intermediate transfer belt 41. The toner images on the photosensitive drums 3Y, 3M, 3C, and 3K formed by the process cartridges 2Y, 2M, 2C, and 2K are transferred to the intermediate transfer belt 41 at the primary transfer nip. The toner image transferred onto the intermediate transfer belt 41 is transferred to a sheet as a transfer medium at the secondary transfer nip. The residual transfer toner remaining on the intermediate transfer belt 41 after passing through the secondary transfer nip is removed by the cleaning device 45.

  Below the intermediate transfer unit 40, there are a first receiving branch path 52, a receiving and conveying roller pair 53, a second receiving and branching path 54, a manual separation roller pair 55, a pre-transfer conveying path 56, a registration roller pair 57, and a conveying belt unit 58. A switchback device 59 is arranged. These components form a conveyance path for paper fed from the paper feed unit 10 or the manual feed tray 51.

  A fixing device 60 is disposed below the intermediate transfer unit 40. In the fixing device 60, a fixing nip is formed between the fixing belt 61 and the pressure roller 62. The sheet on which the full-color toner image is transferred at the secondary transfer nip is conveyed into the fixing device 60 by the conveying belt unit 58, and the toner image is fixed by pressure and heat received at the fixing nip. The sheet on which the toner image is fixed is sent out toward the paper discharge roller pair 63.

  In the single-sided print mode in which an image is formed only on the first surface of the paper P, the paper P sandwiched between the paper discharge nips between the rollers of the paper discharge roller pair 63 is directly discharged out of the apparatus and discharged into the paper discharge tray 64. Stacked on top. In the double-sided print mode in which images are formed on both sides of the paper P, the paper P sandwiched in the paper discharge nip is returned in the reverse direction and enters the switchback device 59. Then, after being turned upside down in the switchback device 59, it is sent again to the secondary transfer nip, and the other side of the image is subjected to image secondary transfer processing and fixing processing.

  The paper supply unit 10 includes four paper supply cassettes 12, paper supply rollers 13, separation roller pairs 14, paper supply paths 15, and conveyance roller pairs 16 arranged in four stages in a paper bank 11. The paper feeding unit 10 rotates the paper feeding roller 13 based on a control signal from the printer unit 1 to separate the uppermost paper P in the paper bundle in the paper feeding cassette 12 into the separation roller pair 14. To send. The paper P that has been separated into one sheet by the separation roller pair 14 and then sent to the paper feed path 15 passes through the transport nips of the plurality of transport roller pairs 16 provided in the paper feed path 15, and the printer unit 1. To the first receiving branch 52.

  A pre-transfer conveyance path 56 for conveying the sheet P immediately before the secondary transfer nip branches into a first reception branch path 52 and a second reception branch path 54 on the upstream side in the sheet conveyance direction. The sheet P sent out from the sheet feeding path 15 of the sheet feeding unit 10 is received by the first receiving branch path 52 of the printer unit 1, and then the receiving transport roller pair 53 disposed in the first receiving branch path 52. Is sent to the pre-transfer conveyance path 56 via the conveyance nip. The paper P manually fed from the manual feed tray 51 is separated into one sheet by the manual separation roller pair 55, then sent out toward the second receiving branch path 54, and sent to the pre-transfer conveyance path 56.

  The scanner 21 fixed on the printer unit 1 has a fixed reading unit and a moving reading unit as reading means for reading an image of a document (not shown). A fixed reading unit having a light source, a reflection mirror, an image reading sensor such as a CCD, and the like is disposed immediately below a first contact glass (not shown) fixed to the upper wall of the casing of the scanner 21 so as to contact the document. Then, when the document conveyed by the ADF 22 passes over the first contact glass, the light emitted from the light source is sequentially reflected by the document surface, and is received by the image reading sensor via a plurality of reflection mirrors. Thus, the original is scanned without moving the optical system including the light source and the reflecting mirror.

  The moving reading unit of the scanner 21 is disposed immediately below a second contact glass (not shown) fixed to the upper wall of the casing of the scanner 21 so as to come into contact with the document, and an optical system including a light source, a reflection mirror, and the like. It can be moved in the left-right direction in the figure. Then, in the process of moving the optical system from the left side to the right side in the figure, the light emitted from the light source is reflected by a document (not shown) placed on the second contact glass and then passed through a plurality of reflecting mirrors. The image is received by an image reading sensor fixed to the scanner body. Accordingly, the original is scanned while moving the optical system.

  Next, the configuration of the process cartridges 2Y, 2M, 2C, and 2K will be described in detail. FIG. 5 is an enlarged configuration diagram showing the configuration of the process cartridge. The process cartridges 2Y, 2M, 2C, and 2K have the same configuration except that the colors of the toners used are different from each other. Therefore, the following description omits the reference numerals indicating the distinction of colors.

  The process cartridge 2 includes a charging device 4 and a developing device 5 around the photosensitive drum 3. The charging device 4 uniformly charges the outer peripheral surface of the photosensitive drum 3. The developing device 5 develops the electrostatic latent image formed on the outer peripheral surface of the photosensitive drum 3 with toner by scanning exposure of the laser light L from the optical writing unit 30.

  In the present embodiment, the photosensitive drum 3 corresponds to an example of the image carrier referred to in the present invention. A combination of the charging device 4, the optical writing unit 30, and the developing device 5 corresponds to an example of the image forming unit referred to in the present invention. Further, the intermediate transfer unit 40 shown in FIG. 4 corresponds to an example of a transfer portion according to the present invention, and the fixing device 60 corresponds to an example of a fixing portion according to the present invention.

  Further, the process cartridge 2 includes a cleaning unit 6 for removing transfer residual toner attached to the outer peripheral surface of the photosensitive drum 3 around the photosensitive drum 3, and a protective agent layer on the outer peripheral surface of the photosensitive drum 3. And a protective layer forming apparatus 70 for forming the film. The cleaning means 6 corresponds to an example of the cleaning means referred to in the present invention, and the protective layer forming apparatus 70 corresponds to an example of the protective layer forming apparatus referred to in the present invention.

  The cleaning means 6 is fixed to the protective layer forming apparatus 70 as described later. The protective layer forming apparatus 70 includes a protective agent supply member 7 a that applies a protective agent to the outer peripheral surface of the photosensitive drum 3, and a protective agent leveling member 8 that equalizes the protective agent applied to the outer peripheral surface of the photosensitive drum 3. have. The protective agent supply unit 7a corresponds to an example of the protective agent supply member according to the present invention, and the protective agent leveling member 8 corresponds to an example of the protective agent leveling member according to the present invention. The protective agent supply member 7a, the image carrier protective agent 7b, and the pressing member 7c may be collectively referred to as a protective agent application device 7.

  The photosensitive drum 3 rotates in the rotation direction indicated by the arrow D3 in FIG. By this rotation, the outer peripheral surface sequentially passes through the charging device 4, the developing device 5, the primary transfer roller 42, the cleaning unit 6, and the protective layer forming device 70 in this order.

  The photoconductor drum 3 is an organic photoconductor having a cylindrical shape and rotating in a rotation direction indicated by an arrow D3 with a central axis of the cylindrical shape as a rotation axis, and a surface protective layer is formed of a polycarbonate-based resin on an outer peripheral surface thereof. Has been. The charging device 4 includes a charging roller 4 a configured by covering a conductive metal core with an intermediate resistance elastic layer. The charging roller 4a is connected to a power source (not shown) and is applied with a predetermined voltage. The charging roller 4 a is disposed with a small gap with respect to the photosensitive drum 3. The minute gap is caused by, for example, winding a spacer member having a certain thickness around the non-image forming regions at both ends of the charging roller 4a to bring the surface of the spacer member into contact with the outer peripheral surface of the photosensitive drum 3. Can be set. Further, the charging device 4 is provided with a charging cleaning means 4b for cleaning in contact with the surface of the charging roller 4a.

  In the developing device 5, a developing sleeve 5 a including a magnetic field generating unit is disposed at a position facing the outer peripheral surface of the photosensitive drum 3. The developing sleeve 5a rotates in the rotation direction indicated by the arrow D2. Below the developing sleeve 5a, there are provided two screws 5b for mixing toner introduced from a toner bottle (not shown) with a magnetic carrier and pumping it up to the developing sleeve 5a while stirring. The developer composed of toner and magnetic carrier pumped up by the developing sleeve 5a is regulated to a predetermined developer layer thickness by the doctor blade 5c, and is carried on the developing sleeve 5a. The surface of the developing sleeve 5a moves in the same direction at the position facing the photosensitive drum 3, while carrying and carrying the developer, and supplies toner to the latent image surface of the photosensitive drum 3 to form a toner image. In the present embodiment, the configuration of the two-component developing type developing device 5 is shown in FIG. 2, but the present invention is not limited to this, and a one-component developing type developing device can also be applied.

  The cleaning means 6 has a cleaning blade 6a and a blade holding member 6b. The blade holding member 6 b is fixed to the case of the protective layer forming apparatus 70. The cleaning blade 6 a is cantilevered by a blade holding member 6 b, and its free end contacts the outer peripheral surface of the photosensitive drum 3 after transfer from the counter direction with respect to the moving direction of the outer peripheral surface of the photosensitive drum 3. Touch. The cleaning blade 6a rubs the outer peripheral surface of the photosensitive drum 3 after the transfer, and removes deposits represented by residual toner remaining on the outer peripheral surface. The material used for the cleaning blade 6a is not particularly limited, and elastic bodies such as urethane rubber, hydrin rubber, silicone rubber, and fluorine rubber can be used singly or in a blend. Further, the contact portion of the rubber blade with the photosensitive drum 3 may be coated with a low friction material or impregnated. Further, in order to adjust the hardness of the elastic body, fillers represented by other organic fine particles and inorganic fine particles may be dispersed therein. The cleaning blade 6a is fixed to a blade holding member 6b made of metal, plastic, ceramic or the like by any method such as adhesion and fusion. In this embodiment, the cleaning blade 6a is made of an insulating rubber, but the cleaning blade 6a may be conductive. Further, instead of the cleaning blade 6a, a cleaning brush in which a bias is applied to a conductive brush having a medium resistance to a low resistance may be used.

  The protective layer forming apparatus according to the present invention can be used not only for applying a protective agent to the surface of the photoreceptor 3 but also as an apparatus for applying a protective agent to the surface of the intermediate transfer belt 41 in FIG. . In this case, the protective layer forming device 70 may be provided adjacent to the intermediate transfer belt cleaning device 45 or may be included in the intermediate transfer belt cleaning device 45. Thereby, it is possible to satisfactorily clean deposits such as toner remaining on the surface of the intermediate transfer belt 41 without being subjected to secondary transfer at the nip portion with the secondary transfer roller 44.

  The shape of the contact portion of the protective agent leveling member can be used not only as a member to which the protective agent is applied but also as a cleaning blade. In this case, as shown in FIG. 3, the shape of the cleaning blade 6 a can be a triangular cross section similar to the contact portion 8 a of the protective agent leveling member. As a result, the pressure per unit area of the cleaning blade is increased, so that the toner can be prevented from slipping through and the blade is worn over time, and a high-quality image can be obtained stably over a long period of time.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Examples 1-16 and Comparative Examples 1-6)
Using the apparatus obtained by modifying the image forming apparatus (image MPC4500, manufactured by Ricoh Co., Ltd.) shown in FIG. 4, the image carrier protecting agent was applied to the surface of the photoconductor as an image carrier to form an image.
In the image forming unit of the image forming apparatus (image MP C4500, manufactured by Ricoh Co., Ltd.), a photoconductor (product equipped with image MP C4500) used in the image forming apparatus was used as an image carrier.
As the image carrier protecting agent, an image carrier protecting agent block having a compounding ratio (mass ratio) of zinc stearate: boron nitride = 9: 1 was used.
As the toner, the toner used in the image forming apparatus (the product equipped with imgio MP C4500) was used.
As the protective agent supply member, a brush roller used in the image forming apparatus (image MP C4500, manufactured by Ricoh Co., Ltd.) was used.

  Next, the type of protective agent leveling member (cross-sectional shape of the contact portion, apex angle D) shown in Table 1, the contact direction of the contact portion of the protective agent leveling member, and the contact of the protective agent leveling member The image forming apparatuses of Examples 1 to 16 and Comparative Examples 1 to 6 were assembled so that the amount of biting into the surface of the image carrier at the contact portion was obtained.

<Comparative Examples 1-2 and Examples 1-16>
In Comparative Examples 1 and 2 and Examples 1 to 16, the protective agent leveling member 8 having the triangular contact section 8a and the holding member 8b as shown in FIG. 3 was used as the protective agent leveling member. . The abutting portion 8a abuts from the counter direction with respect to the rotation direction (arrow D1) of the photosensitive drum 3 by a holding member 8b fixed to the case 6c of the protective layer forming apparatus 70, and serves as a protective agent supply member 7a. It is supported at a position downstream of the brush roller.
・ Material of contact part: Urethane rubber ・ Hardness of contact part: 65 degrees (Shore A hardness, JIS K6253: 2001, measured at 25 ° C. by durometer type A)
・ Height of contact part: 8mm
-Material of holding member: SUS304
-Manufacturing method of protective agent leveling member: A contact portion was prepared by cutting urethane rubber into a desired shape. Alternatively, liquid urethane rubber was poured into a casting mold and cured to prepare a contact portion. The produced contact part was hot-melt bonded to the holding member to produce a protective material leveling member.
・ Adjustment method of the apex angle D of the abutting portion: The abutting portion can be changed by changing the angle at which the urethane rubber is cut or by changing the shape of the casting for pouring liquid urethane rubber into the casting. The apex angle D was adjusted.
Method for adjusting the amount of biting of the abutting portion into the surface of the image carrier: The amount of biting was adjusted by sandwiching a spacer between the holding member and the location where the holding member was attached.

<Comparative Example 3>
Comparative Example 3 is a right-angle trailing method. As shown in FIG. 1, the protective agent leveling member 520 includes a blade 521 and a holding member 522. The blade 521 is disposed at a position downstream of the protective agent coating device 510 with respect to the rotation direction of the photosensitive drum 550 (arrow AD1). The blade 521 is brought into contact with the case 501 via the holding member 522 so that the outer peripheral surface 551 of the photosensitive drum 550 is in contact with the leading edge portion 521a having a right angle from the trailing direction with respect to the rotation direction (arrow AD1). It is fixed.
-Blade material: Urethane rubber-Holding member material: SUS304

<Comparative Examples 4 and 5>
Comparative Examples 4 and 5 are a right-angle counter system, and the protective agent leveling member 610 has a blade 611 and a holding member 612 as shown in FIG. In FIG. 2, the blade 611 has a tip edge portion 611a abutting on the outer peripheral surface 551 of the photosensitive drum 550 from the counter direction with respect to the rotation direction (arrow AD1). Further, the edge portion 611a of the blade 611 has a ridge line portion of a right angle (90 degrees) shape, and the right edge (90 degrees) shape of the edge edge portion 611a contacts the outer peripheral surface 551 of the photosensitive drum 550. It touches.
-Blade material: Urethane rubber-Holding member material: SUS304

<Comparative Example 6>
The comparative example 6 is an obtuse angle counter system, and the protective agent leveling member 610 has a blade 611 and a holding member 612 as shown in FIG. In FIG. 2, the blade 611 has a tip edge portion 611a abutting on the outer peripheral surface 551 of the photosensitive drum 550 from the counter direction with respect to the rotation direction (arrow AD1). Further, the leading edge portion 611a of the blade 611 has an obtuse angle (120 degrees) in the ridge line portion, and the leading edge portion 611a having the obtuse angle (120 degrees) shape contacts the outer peripheral surface 551 of the photosensitive drum 550. It touches.
-Blade material: Urethane rubber-Holding member material: SUS304

  Next, in the assembled image forming apparatuses of Examples 1 to 15 and Comparative Examples 1 to 6, the amount of biting into the image carrier surface of the contact portion of the protective agent leveling member was measured as follows. The amount of biting of the contact portion of the protective agent leveling member into the surface of the image carrier, the wear resistance of the contact portion of the protective agent leveling member, and the cleaning property were evaluated as follows. The results are shown in Table 1.

<Amount of biting into the surface of the image carrier at the contact portion of the protective agent leveling member or blade>
The amount of biting into the surface of the image carrier at the contact portion of the protective agent leveling member or the blade was performed using a dedicated instrument (custom product). In the state where the image carrier is not attached to the shaft of the image carrier, the special instrument (a circular instrument having 30 blades with different lengths; the blade length corresponds to the amount of biting) is attached. The length of the blade contacted by the contact portion of the protective agent leveling member or the tip of the blade was determined, and the amount of biting was measured from the length of the blade at that time.

<Abrasion resistance of contact portion of protective agent leveling member or tip of blade>
Using a test chart (A4 size) with an image area ratio of 5%, 100,000 images were output, and the wear amount of the contact portion of the protective agent leveling member or the tip of the blade was measured using a shape measuring laser microscope (VK). -8500 (manufactured by Keyence Corporation), and the wear resistance of the contact portion of the protective agent leveling member or the tip of the blade was evaluated according to the following criteria.
〔Evaluation criteria〕
◎: Contact part of the protective agent leveling member or the tip of the blade does not wear ○: Contact part of the protective agent leveling member or the tip of the blade is worn slightly, but there is no problem △: Protective agent leveling The contact part of the member or the tip of the blade is worn, and an abnormal image (image that appears as black streaks on the image) occurs with time (about 20,000 sheets). The contact part or the tip of the blade is considerably worn, and an abnormal image (an image that appears as a black streak on the image) is generated from an early stage (about 5,000 sheets).

<Cleanability>
After running 500 sheets, it is replaced with a new image carrier, and a 2 mm-thick linear sponge tape (Scotch tape 4016, manufactured by Sumitomo 3M Co., Ltd.) is used downstream of the cleaning blade and at the upper end of the opening of the developing means. Then, a “through toner catcher” (felt with a thickness of 1 mm, 8 mm × 310 mm, manufactured by Ashiya Co., Ltd.) was attached. After 100 runs (passing) using a chart with an image area ratio of 5%, the toner slipped downstream of the cleaning blade during the run (passing) of 20 sheets with an image area ratio of 5% is passed through the “slip-through”. The toner was collected by a “toner catcher”, and the cleaning property was evaluated by visual observation according to the following criteria.
〔Evaluation criteria〕
A: There is no toner slipping. ○: There is almost no toner slipping. Δ: Toner slipping occurs, and an abnormal image (image appearing as black streaks on the image) may occur. And abnormal images (images that appear as black streaks on the image) frequently occur

* The cross-sectional shape and apex angle of the contact portion in Comparative Examples 3 to 6 mean the shape and edge angle of the tip of the blade.

As an aspect of this invention, it is as follows, for example.
<1> An image carrier protecting agent, a protective agent supplying member that supplies the image carrier protecting agent to the surface of the image carrier,
A protective agent leveling member for leveling the image carrier protective agent supplied on the image carrier;
Having at least
The protective agent leveling member has an abutting portion having a triangular section with an apex angle D of 15 to 80 degrees, and the abutting portion abuts on the surface of the image carrier. Forming device.
<2> The protective layer forming apparatus according to <1>, wherein the apex angle D is 40 degrees to 60 degrees.
<3> The protective layer formation according to any one of <1> to <2>, wherein an amount of biting into the surface of the image carrier at the contact portion of the protective agent leveling member is 0.1 mm to 1.5 mm. Device.
<4> The protective layer forming apparatus according to any one of <1> to <3>, wherein the image carrier protecting agent contains a fatty acid metal salt.
<5> The protective layer forming apparatus according to <4>, wherein the fatty acid metal salt is zinc stearate.
<6> The protective layer forming apparatus according to any one of <4> to <5>, wherein the image carrier protective agent contains an inorganic lubricant.
<7> The protective layer forming apparatus according to <6>, wherein the inorganic lubricant is at least one selected from boron nitride, mica, and talc.
<8> An image carrier, an electrostatic latent image forming unit that forms an electrostatic latent image on the image carrier, and a developing unit that develops the electrostatic latent image with toner to form a visible image Transfer means for transferring the visible image onto a recording medium; and protective layer forming means for forming a protective layer by applying an image carrier protective agent to the surface of the image carrier after the transfer of the visible image. And an image forming apparatus having a cleaning means for removing the residue on the image carrier,
An image forming apparatus, wherein the protective layer forming unit is the protective layer forming apparatus according to any one of <1> to <7>.
<9> The image forming apparatus according to <8>, wherein the cleaning unit is an elastic cleaning blade.
<10> An image carrier, an electrostatic latent image forming unit that forms an electrostatic latent image on the image carrier, a developing unit that develops the electrostatic latent image with toner to form a visible image, Transfer means for transferring the visible image onto a recording medium, protective layer forming means for forming a protective layer by applying an image carrier protecting agent to the surface of the image carrier after transferring the visible image; and A process cartridge having at least one means selected from cleaning means for removing the residue on the image carrier,
A process cartridge, wherein the protective layer forming means is the protective layer forming apparatus according to any one of <1> to <7>.

Japanese Patent Laid-Open No. 10-260614 JP 2003-57996 A JP 2002-244485 A JP 2006-154747 A JP 2001-305907 A JP 2006-251751 A JP 2007-264347 A

3 Image carrier (photoconductor)
DESCRIPTION OF SYMBOLS 4 Charging device 4a Charging roller 4b Charging cleaning means 5 Developing device 6 Cleaning device 6a Cleaning blade 6b Blade holding member 7 Protection agent coating device 7a Brush roller 7b Image carrier protecting agent 7c Pressure applying member 70 Protective layer forming device

Claims (10)

An image carrier protective agent; and a protective agent supply member that supplies the image carrier protective agent to the surface of the image carrier;
A protective agent leveling member for leveling the image carrier protective agent supplied on the image carrier;
Having at least
The protective agent leveling member has an abutting portion having a triangular section with an apex angle D of 15 to 80 degrees, and the abutting portion abuts on the surface of the image carrier. Forming equipment.   The protective layer forming apparatus according to claim 1, wherein the apex angle D is 40 degrees to 60 degrees.   The protective layer forming apparatus according to claim 1, wherein an amount of biting into the surface of the image carrier at the contact portion of the protective agent leveling member is 0.1 mm to 1.5 mm.   The protective layer forming apparatus according to claim 1, wherein the image carrier protecting agent contains a fatty acid metal salt.   The protective layer forming apparatus according to claim 4, wherein the fatty acid metal salt is zinc stearate.   The protective layer forming apparatus according to claim 4, wherein the image carrier protective agent contains an inorganic lubricant.   The protective layer forming apparatus according to claim 6, wherein the inorganic lubricant is at least one selected from boron nitride, mica, and talc. An image bearing member; an electrostatic latent image forming unit that forms an electrostatic latent image on the image bearing member; a developing unit that develops the electrostatic latent image with toner to form a visible image; Transfer means for transferring a visible image onto a recording medium; protective layer forming means for forming a protective layer by applying an image carrier protecting agent to the surface of the image carrier after transferring the visible image; An image forming apparatus having a cleaning means for removing the residue on the image carrier,
8. The image forming apparatus according to claim 1, wherein the protective layer forming means is the protective layer forming apparatus according to claim 1.   The image forming apparatus according to claim 8, wherein the cleaning unit is an elastic cleaning blade. An image bearing member; an electrostatic latent image forming unit that forms an electrostatic latent image on the image bearing member; a developing unit that develops the electrostatic latent image with toner to form a visible image; Transfer means for transferring an image onto a recording medium, protective layer forming means for forming a protective layer by applying an image carrier protective agent to the surface of the image carrier after transferring the visible image, and the image carrier A process cartridge having at least one means selected from cleaning means for removing residues on the top,
8. A process cartridge according to claim 1, wherein the protective layer forming means is the protective layer forming apparatus according to claim 1.