JP5989581B2 - Elastic roller, developing device and image forming apparatus - Google Patents

Description

  The present invention relates to an elastic roller, a developing device, and an image forming apparatus. More specifically, the present invention has a life corresponding to the life of the toner, and can be reused by regenerating it at a regeneration time corresponding to the toner replacement time. The present invention relates to an elastic roller, an image forming apparatus having the elastic roller, and an image forming apparatus in which the elastic roller can be regenerated and used in accordance with toner replacement timing.

  Various printers such as laser printers and video printers, copiers, facsimiles, and multi-function machines of these types employ various image forming apparatuses using an electrophotographic system, for example. An image forming apparatus using an electrophotographic method includes an elastic roller having an elastic layer disposed on the outer peripheral surface of a shaft body, a surface layer disposed on the outer peripheral surface of the elastic layer as desired, for example, a cleaning roller, a charging roller, A developing roller, a toner conveying roller, a transfer roller, and the like are provided.

  Such an elastic roller deteriorates the quality of an image formed by the image forming apparatus when the elastic layer or the surface layer is damaged and does not perform its intended function. In particular, since the developing roller carries the developer on its outer peripheral surface, the functional deterioration of the elastic layer or the surface layer greatly affects the image quality.

  Therefore, as a developing roller that focuses on durability, for example, Patent Document 1 discloses that “the toner that adheres electrically to the end seal member that contacts the developing roller is prevented from entering, and the durability is excellent. “Developing roller for forming a quality image” (column 0003), “A developing roller that holds toner on the outer peripheral surface thereof by an electrophotographic method and conveys it to a developing region, and a roller member that is rotatably held, and the above roller member A conductive member made of a conductive material that holds the toner and formed in the developing region portion of the outer peripheral surface of the toner, and a non-conductive member made of a non-conductive material that is formed at the end of the conductive member and prevents toner adhesion. The developing roller is characterized in that (Claim 1). Here, in Patent Document 1, “the conductive member 2 is a conductive resin layer, for example, formed of melamine resin”, “non-conductive member 3 is formed of polycarbonate, which is a non-conductive resin layer. Is specifically described (column 0010).

JP 2004-191430 A

However, it is unavoidable that the elastic layer or the surface layer of the elastic roller including the developing roller is deteriorated, and the elastic roller having the reduced function is replaced with a new elastic roller.
Further, both ends of the elastic roller in the axial direction are likely to be loaded by the outer diameter jumping, and there is a problem that the ends of the elastic roller are peeled off by using the elastic roller for a long period of time.

  Conventionally, the replacement timing of the conductive roller can be set as a rough standard by confirming the quality of the formed image. However, it varies depending on the use environment and the use situation and is likely to be indeterminate.

  The present invention is based on the fact that the main cause of the functional deterioration of the elastic roller is the separation at both ends of the elastic roller, and the timing of the functional deterioration of the elastic roller is made constant, and both ends of the elastic roller It is an object of the present invention to provide such an elastic roller which can be used semi-permanently by regenerating an elastic roller whose function has been reduced by regenerating. Another object of the present invention is to provide a developing device and an image forming apparatus having a long service life by using an elastic roller semipermanently by regenerating periodically.

  An image forming apparatus using an electrophotographic method generally includes an image carrier on which an electrostatic latent image is formed and an elastic roller that is disposed facing the image carrier and carries and conveys a developer.

  The inventor of the present invention is able to align the functional deterioration of the elastic roller in which the urethane coat layer containing specific particles is formed on the outer peripheral surfaces of both ends of the elastic layer at a certain time. It was found that the elastic roller can be recycled by periodically forming a new urethane coat layer on the outer peripheral surface of both ends of the elastic roller.

Therefore, means for solving the above-mentioned problems are:
(1) A shaft, an elastic layer formed on the outer peripheral surface of the shaft, and an outer surface of the elastic layer, the polyol and the silane coupling agent formed on both ends in the axial direction of the elastic layer It is an elastic roller characterized by comprising an end coat layer containing a resin obtained by reacting and boron nitride particles,
(2) A developing device comprising the elastic roller according to (1),
(3) An image forming apparatus comprising the developing device according to (2).

  In the elastic roller according to the present invention, since both end portions in the axial direction of the elastic layer are covered with the end coat layer containing boron nitride particles, the life of the elastic roller is, for example, about 6000 sheets as the number of image formations. Therefore, it is possible to predict the replacement timing of the elastic roller based on the number of images consumed, and to expose the elastic layer after peeling off the end coat layers formed on both outer peripheral surfaces of the replaced elastic roller. By forming an end coat layer containing boron nitride particles newly on the outer peripheral surfaces of both ends, a reusable elastic roller can be obtained. Therefore, the elastic roller according to the present invention can be used semipermanently by repeating use and regeneration.

  Further, according to the present invention, it is possible to predict the replacement timing of the elastic roller by the number of consumed images. Therefore, it is possible to accurately replace the elastic roller periodically, and to use and regenerate the same elastic roller. By being able to be used repeatedly, it is possible to provide a developing device and an image forming apparatus that do not require purchasing a new elastic roller each time.

  Further, according to the present invention, it is possible to provide an image forming apparatus capable of revealing an appropriate replacement time of the elastic roller, and an elastic roller and a developing device in which the image forming apparatus can indicate an appropriate replacement time of the elastic roller.

FIG. 1 is a perspective view showing an example of an elastic roller according to the present invention. FIG. 2 is a schematic view showing an example of the developing cartridge according to the present invention. FIG. 3 is a schematic view showing an example of an image forming apparatus according to the present invention.

  The elastic roller according to the present invention will be described with an example. As shown in FIG. 1, an elastic roller 1 that is an example of an elastic roller according to the present invention includes a shaft body 2, an elastic layer 3, and a coat layer 4.

  The shaft body 2 is basically the same as the shaft body in a conventionally known developing roller. The shaft body 2 is a so-called “core metal” composed of iron, aluminum, stainless steel, brass, or the like, and has good conductive characteristics. The shaft body 2 may be a shaft body made conductive by plating an insulating core body such as a thermoplastic resin or a thermosetting resin.

  The elastic layer 3 is basically the same as the elastic layer in a conventionally known developing roller. The elastic layer 3 is formed by curing a conductive composition described later on the outer peripheral surface of the shaft body 2, and preferably has a JIS A hardness of 20 to 70. When the elastic layer 3 has a JIS A hardness (JIS K6301) of 20 to 70, the contact area between the elastic roller 1 and the contacted body can be increased, Excellent compression set.

The elastic layer 3 preferably has a volume resistivity in the range of 10 ¹ to 10 ⁷ Ω · cm and / or an electrical resistivity in the range of 10 ¹ to 10 ⁹ Ω. When the volume resistivity and / or the electrical resistivity of the elastic layer 3 are within the above ranges, when the elastic roller 1 is mounted on the image forming apparatus, the developer is supported and supplied as desired to obtain the desired quality. It is possible to contribute to forming an image having the same. The volume resistivity can be measured according to a method defined in JIS K6911 (applied voltage is 100 V). The electrical resistivity is measured by, for example, using an electrical resistance meter (trade name: ULTRA HIGH RESISTANCE METER R8340A, manufactured by Advantest Co., Ltd.), placing the elastic roller 1 horizontally, a thickness of 5 mm, a width of 30 mm, and an elastic roller. The electrode body is a gold-plated plate having a length on which the entire elastic layer 3 can be placed, and a load of 500 g is supported on both ends of the shaft body 2 of the elastic roller 1 so that the shaft body 2 and the electrode DC100V is applied between the values, the value of the electric resistance meter after 1 second is read, and the measurement can be performed according to the method of setting this value as the electric resistance value.

  The elastic layer 3 can contribute to forming a fog-free image even in a low-humidity environment when the elastic roller 1 is mounted on the image forming apparatus. The elastic layer 3 has an elongation of 300 to 1200% and a break of 3 to 25 MPa. It is preferable that at least one physical property of the strength is satisfied, and it is particularly preferable that both physical properties are satisfied. The elongation is more preferably 400 to 800%, and particularly preferably 500 to 800%. If the elastic layer 3 has an elongation in the above range, even if the elastic roller 1 is mounted on the image forming apparatus so that the pressing margin against the contacted body such as the photosensitive drum is increased, the pressing margin passes through the pressing margin. This makes it difficult to damage the developing agent, and can greatly contribute to the formation of a fog-free image even in a low humidity environment. The breaking strength is more preferably 10 to 25 MPa, and particularly preferably 15 to 25 MPa. If the elastic layer 3 has a breaking strength in the above range, even if the elastic roller 1 is attached to the image forming apparatus so that the pressing allowance against the contacted body such as a photosensitive drum becomes large, the elastic roller 1 The elastic roller 1 is not subjected to such a load as to cause destruction, which can greatly contribute to the formation of a fog-free image even in a low humidity environment. The elongation and the breaking strength are measured with a test piece (10 mm × 50 mm × thickness 40 μm) cut out from the elastic layer 3 of the elastic roller 1 or a test piece (10 mm) made of a rubber composition forming the elastic layer 3. In accordance with the measurement method described in JIS K7113 under the conditions that the measurement temperature is 25 ± 2 ° C., the tensile speed is 100 mm / min, and the distance between the grips of the test piece is 50 mm. This is the value when measured. In order to adjust the elongation and breaking strength of the elastic layer 3 to the above ranges, for example, a method of adjusting the blending amount of a filler or an inorganic filler in a conductive composition described later, an addition-curable liquid conductive silicone rubber described later The method etc. which adjust the compounding quantity of (D) organohydrogen polysiloxane in a composition are mentioned.

  The thickness of the elastic layer 3 is preferably 1 mm or more in that a uniform nip width between the contacted body and the elastic layer 3 can be secured in the contact state with the contacted body. It is particularly preferably 5 mm or more. On the other hand, the upper limit of the thickness of the elastic layer 3 is not particularly limited as long as the outer diameter accuracy of the elastic layer 3 is not impaired. Generally, if the thickness of the elastic layer 3 is excessively increased, the production cost of the elastic layer 3 increases. In consideration of practical production costs, the thickness of the elastic layer 3 is preferably 30 mm or less, and more preferably 20 mm or less. The thickness of the elastic layer 3 is appropriately selected according to the hardness of the elastic layer 3, such as JIS A hardness, in order to achieve a desired nip width.

  As shown in FIG. 1, the coat layer 4 is an outer peripheral surface of the elastic layer 3, an end coat layer 4 </ b> A formed on each of both ends in the axial direction of the elastic layer 3, and an outer peripheral surface of the elastic layer 3. And the center coat layer 4B formed between the end coat layers 4A in the axial direction. As described above, when the end coat layer 4A is provided on both ends in the axial direction of the elastic layer 3, the end coat layer 4A is worn over time and leaks a bias current to the outside as will be described later. be able to. Further, when the center coat layer 4B is provided, a desired amount of developer charged to a desired charge amount can be carried and conveyed and supplied to the image carrier, which can greatly contribute to the formation of a high quality image.

  Each of the end coat layers 4 </ b> A is formed on the outer peripheral surface of both ends of the elastic layer 3 in the axial direction. Preferably, as shown in FIG. 2, each of the end coat layers 4A extends toward the center beyond at least the region in contact with the developer seal member 25 when mounted on the developing device. Specifically, the elastic layer 3 has a central end 4C that extends beyond the developer seal member 25 and reaches the inside of the developer regulating member 24 arranged in parallel with the developer seal member 25. It is formed on the outer peripheral surface. In other words, each of the end coat layers 4A is formed on the outer peripheral surface of the elastic layer 3 in contact with the developer seal member 25 and the developer regulating member 24 when mounted on the developing device. More specifically, although it depends on the axial length of the elastic roller 1, each end coat layer 4A has an elastic layer when mounted on an image forming apparatus that forms an image on A3 paper (JIS). 3 is formed on the outer peripheral surface of 5 to 15 mm from each end edge toward the center side. In general, it is assumed that the developer physically adheres to the boundary portion between the developer seal member 25 and the developer regulating member 24 and is likely to cause developer leakage. However, the elastic roller 1 has the end coat layer 4A. Since it is formed beyond the boundary portion, even if it is mounted on a developing device, it is possible to greatly reduce the amount of developer in the vicinity of the boundary that easily adheres physically, and to highly prevent developer leakage. .

  The end coat layer 4A contains a resin obtained by reacting a polyol and a silane coupling agent (hereinafter sometimes simply referred to as “resin”) and boron nitride particles.

  The resin obtained by reacting the polyol and the silane coupling agent is contained in the end coat layer 4A as a main component, for example, in a proportion of 50% by mass or more with respect to the total mass of the end coat layer 4A. . When the resin is contained in such a ratio, the end coat layer 4A is easily worn to the extent that the bias current leaks in accordance with the replacement timing of the elastic roller 1, and the center coat layer 4B and the elastic layer 3 are expected to be worn. It is possible to substantially prevent wear and damage to such an extent that the function is impaired.

  The resin may be a resin obtained by reacting a polyol and a silane coupling agent. Examples of the polyol include various types of polyols, preferably the same as the polyol constituting the urethane resin, more preferably polyester polyols and polyether polyols.

  The silane coupling agent only needs to have a substituent that reacts with the hydroxyl group of the polyol, for example, an organic group containing an epoxy group, a vinyl group, and a (meth) acryloyl group, and an alkoxy group. Examples include silane coupling agents having a xylpropyl group, silane coupling agents having a vinyl group, and silane coupling agents having a γ-methacryloxypropyl group. Specific examples of such silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, and γ-glycidoxypropyl. Examples include methyldiethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and γ-methacryloxypropyltrimethoxysilane.

  The resin is a resin obtained by reacting a hydroxyl group of a polyol with a substituent of a silane coupling agent. Reaction of a polyol and a silane coupling agent can be implemented at the temperature of 120 to 160 degreeC, for example.

  Examples of the boron nitride particles include a crystal structure such as a cubic zinc blende structure, a hexagonal graphite structure, and a hexagonal wurtzite structure. Among these, a hexagonal graphite structure is included. A similar structure is preferred. Such boron nitride particles may be produced as appropriate or commercially available products may be used. Boron nitride particles are available from, for example, Advance Ceramics, Saint Gobain Advance Ceramics, and the like.

  The boron nitride particles contained in the end coat layer 4A usually have an average particle size of 0.1 to 50 μm, preferably 1 to 20 μm. When the particle size of the boron nitride particles is within the above range, there is an advantage that wear resistance is improved.

  In general, the boron nitride particles contained in the end coat layer 4A are 0.1 to 30 parts by mass, preferably 0.5 to 30 parts by mass with respect to 100 parts by mass of the resin. When the content of the boron nitride particles is within the above range, the lifetime of the end coat layer 4A can be adjusted by changing the content of the boron nitride particles.

  The end coat layer 4A may contain various resin compositions, for example, various additives usually used in various resin compositions. Examples of such additives include lubricants, catalysts, amines, auxiliary solvents, and the like.

  The end coat layer 4A is set to a layer thickness corresponding to the replacement timing of the elastic roller in consideration of the amount of wear, and is usually selected from a range of 0.1 to 50 μm. For example, when setting the number of printable sheets in an image forming apparatus such as a simple printer or a personal printer, that is, when the elastic roller replacement time is set to 3000 to 6000 sheets, the layer thickness is set to 7 to 13 μm. When the number of printable sheets is set to 100,000 in the forming apparatus, the layer thickness is set to 15 to 25 μm.

  The center coat layer 4B is formed between the end coat layers 4A, that is, at the center of the elastic layer 3 so as to be in contact with each of the end coat layers 4A.

  The center coat layer 4B is disposed between the end coat layers 4A and contains a urethane resin, a conductivity-imparting agent, and filler particles, and is conductive.

  The urethane resin may be a known urethane resin, and is usually obtained from a polyol and a polyisocyanate. The polyol is preferably a polyester polyol or a polyether polyol in that the object of the present invention can be well achieved. Examples of the polyisocyanate include aliphatic polyisocyanates and aromatic polyisocyanates.

  The conductivity-imparting agent is not particularly limited as long as it has conductivity, and examples thereof include conductive powders such as conductive carbon, carbons for rubber, metals, conductive polymers, and ionic liquids.

Examples of the filler particles include silica. Although not particularly limited, a silica-based filler can be used. Examples of the silica-based filler include fumed silica, precipitated silica, etc., and surface-treated silica having a high reinforcing effect, which is surface-treated with a silane coupling agent represented by a general formula RSi (OR ′) _3. System fillers are preferred. Here, R in the general formula is a glycidyl group, vinyl group, aminopropyl group, methacryloxy group, N-phenylaminopropyl group, mercapto group or the like, and R ′ in the general formula is a methyl group or an ethyl group. . The silane coupling agent represented by the general formula can be easily obtained, for example, as trade names “KBM1003” and “KBE402” manufactured by Shin-Etsu Chemical Co., Ltd. Such a silica-based filler surface-treated with a silane coupling agent can be obtained by treating the surface of the silica-based filler according to a conventional method. In addition, a commercial item may be used for the silica type filler surface-treated with the silane coupling agent. M.M. A trade name “Zeothix 95” manufactured by HUBER Co., Ltd. is available. The average particle diameter of the filler particles is not particularly limited, but is preferably 1 to 80 μm, for example, and particularly preferably 1 to 40 μm. The average particle diameter of the filler particles can be measured as a weight average value (or median diameter) or the like using, for example, a particle size distribution measuring apparatus such as a laser light diffraction method.

  The filler particles are contained in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the urethane resin in that the amount of physical developer transported in the elastic roller 1 can be maintained substantially the same over a long period of time. The content is preferably 1 to 15 parts by mass.

  The center coat layer 4B is substantially free of boron nitride particles contained in the end coat layer 4A. Here, in the present invention, “substantially free of boron nitride particles” means that the central coat layer 4B does not actively contain boron nitride particles, and the boron nitride particles are completely absent. In addition to the above, it is a concept that includes a case where the boron nitride particles are contained in a content that does not exhibit the effect exhibited by the boron nitride particles. Examples of the case where the boron nitride particles are contained in a content that does not exhibit the effect exhibited by the boron nitride particles include a case where the boron nitride particles of the end coat layer 4A enter the central coat layer 4B and remain in the central coat layer 4B. In addition, content which does not exhibit the effect which a boron nitride particle show | plays is a boron nitride particle 0.1 mass part or less with respect to 100 mass parts of said urethane resins, for example.

  The center coat layer 4B may be formed thicker or thinner than the end coat layer 4A, but preferably has the same layer thickness as the end coat layer 4A, usually 0.1 to 50 μm. It is preferably selected from a range. When the central coat layer 4B is formed in this way, a desired amount of developer charged to a desired charge amount can be carried on the surface and supplied to the image carrier.

  As described above, the coat layer 4 includes the end coat layer 4A formed on each of both ends in the axial direction of the elastic layer 3, and the center coat layer 4B formed between the end coat layers 4A. The end coat layer 4A and the center coat layer 4B may be formed without overlapping each other, and the end of the center coat layer 4B and the end of the end coat layer 4A are overlapped. It may be formed. For example, in the present invention, the coat layer can be arranged such that the center coat layer is disposed on the entire outer peripheral surface of the elastic layer 3 and the end coat layers are overlapped on both ends in the axial direction of the center coat layer.

  The elastic roller 1 is manufactured by forming the elastic layer 3 on the outer peripheral surface of the shaft body 2 and further forming the coat layer 4 on the outer peripheral surface of the elastic layer 3. In order to manufacture the elastic roller 1, first, the shaft body 2 is prepared. For example, the shaft body 2 is prepared in a desired shape by a known method. The shaft body 2 may be coated with a primer before the elastic layer 3 is formed. Although there is no restriction | limiting in particular as a primer apply | coated to the shaft body 2, The resin similar to the material which forms the primer layer which adhere | attaches or adhere | attaches the elastic layer 3 and the coating layer 4, and a crosslinking agent are mentioned. The primer is dissolved in a solvent or the like as desired, and is applied to the outer peripheral surface of the shaft body according to a conventional method such as a dipping method or a spray method.

  The elastic layer 3 is formed by heat-curing the conductive composition on the outer peripheral surface of the shaft body 2. As an electroconductive composition, rubber | gum, electroconductivity imparting agent, and various additives depending on necessity are contained. Examples of the rubber include silicone or silicone-modified rubber, nitrile rubber, ethylene propylene rubber (including ethylene propylene diene rubber), styrene butadiene rubber, butadiene rubber, isoprene rubber, natural rubber, acrylic rubber, chloroprene rubber, butyl rubber, and epichlorohydrin. Examples thereof include rubbers such as rubber, urethane rubber, and fluorine rubber. Silicone or silicone-modified rubber or urethane rubber is preferable, and silicone or silicone-modified rubber is particularly preferable in terms of excellent heat resistance and charging characteristics. These rubbers may be liquid or millable. The electroconductivity imparting agent is not particularly limited as long as it has electroconductivity, and examples thereof include electroconductive powder such as electroconductive carbon, carbon for rubber, metal, and electroconductive polymer. Various additives include, for example, auxiliary agents such as chain extenders and crosslinking agents, catalysts, dispersants, foaming agents, anti-aging agents, antioxidants, fillers, pigments, colorants, processing aids, softening agents, Examples thereof include a plasticizer, an emulsifier, a heat resistance improver, a flame retardant improver, an acid acceptor, a heat conductivity improver, a release agent, and a solvent.

  The elastic layer 3 is formed on the outer peripheral surface of the shaft body 2 by using such a conductive composition, for example, by performing heat curing and molding simultaneously or continuously by a known molding method. The method for curing the conductive composition may be any method that can apply heat necessary for curing the conductive composition, and the method for forming the elastic layer 3 may be continuous vulcanization by extrusion, pressing, molding by injection, etc. There is no particular limitation. The heating temperature for curing the conductive composition is 100 to 500 ° C., particularly 120 to 300 ° C., in the case of an addition-curable millable conductive silicone rubber composition, and the time is several seconds to 1 hour, particularly 10 seconds or more. ~ 35 minutes or less is preferable, and in the case of an addition-curable liquid conductive silicone rubber composition, it is 100 to 300 ° C, particularly 110 to 200 ° C, and the time is 5 minutes to 5 hours, particularly 1 to 3 hours. Is preferred. In addition, in the case of an addition-curable millable conductive silicone rubber composition, if necessary, the curing conditions are about 100 to 200 ° C. for about 1 to 20 hours, and in the case of an addition-curable liquid conductive silicone rubber composition. Secondary vulcanization may be performed at 120 to 250 ° C. under curing conditions for about 2 to 70 hours. In addition, the conductive composition can be foamed and cured by a known method to easily form a sponge-like elastic layer having bubbles.

  The elastic layer 3 formed in this way has its surface polished and ground as desired to adjust the outer diameter, surface state, and the like. In addition, the elastic layer 3 thus formed may be provided with a primer layer before the urethane coat layer 4 is formed.

  The coat layer 4 includes the elastic layer 3 formed as described above or the first resin composition capable of forming the end coat layer 4A on the outer peripheral surface of the primer layer formed as desired, and the center coat layer. The second resin composition capable of forming 4B is applied, and then the applied first resin composition and second resin composition are heated and cured to form. Here, when the end coat layer 4A and the center coat layer 4B are formed adjacent to each other without overlapping, the outer periphery of the elastic layer 3 on which one of the end coat layer 4A and the center coat layer 4B is formed. After the second resin composition or the first resin composition capable of forming the other is coated on the outer peripheral surface of the elastic layer 3 on which the other is formed and the other is formed, the first can be formed. By coating and curing the resin composition or the second resin composition, the end coat layer 4A and the center coat layer 4B adjacent to each other can be formed on the outer peripheral surface of the elastic layer 3. In the case of forming one over the other, the second resin composition or the first resin composition capable of forming the other on the outer peripheral surface of the elastic layer 3 is applied and cured, and then the other is formed. The coating layer 4 can be formed on the outer peripheral surface of the elastic layer 3 by applying and curing the first resin composition or the second resin composition capable of forming one on the outer peripheral surface of the elastic layer 3. it can.

  Specifically, first, a first resin composition capable of forming the end coat layer 4A and a second resin composition capable of forming the center coat layer 4B are prepared. As 1st resin composition, the polyol which is the precursor which forms the said resin, a silane coupling agent, boron nitride particle, and various additives, such as a filler depending on necessity, are contained. Therefore, the end coat layer 4 </ b> A is formed by applying and curing a first resin composition containing a polyol, a silane coupling agent, boron nitride particles, and optionally various additives on the outer peripheral surface of the elastic layer 3. The contents of the polyol, the silane coupling agent, and the boron nitride particles in the first resin composition are basically the same as the contents of the respective components in the end coat layer 4A, and the contents of various additives are appropriately determined. Adjusted to In the first resin composition, the polyol, the silane coupling agent, the boron nitride particles, and the like are as described above.

  As a 2nd resin composition, the urethane resin composition containing the urethane adjustment component which is the precursor which forms the said urethane resin, electroconductivity imparting agent, filler particle | grains, and various additives depending on necessity can be mentioned. Therefore, the center coat layer 4B is formed by applying and curing a second resin composition containing a urethane adjusting component, a conductivity imparting agent, filler particles, and various additives as required on the outer peripheral surface of the elastic layer 3. Can do. The contents of the urethane adjusting component, the conductivity-imparting agent and the filler particles in the second resin composition are basically the same as the contents of the respective components in the center coat layer 4B, and the contents of various additives are appropriately determined. Adjusted to In the second resin composition, the filler particles and various additives are as described above.

  The coating of the first resin composition and the second resin composition (hereinafter sometimes collectively referred to as a resin composition) is, for example, a coating method of coating a coating liquid of the resin composition, This is performed by a known coating method such as a dipping method in which the elastic layer 3 or the like is immersed in a coating liquid, or a spray coating method in which the coating liquid is sprayed on the elastic layer 3 or the like. The resin composition may be applied as it is, and for example, alcohol such as methanol and ethanol, aromatic solvent such as xylene and toluene, ester solvent such as ethyl acetate and butyl acetate, etc. You may apply the coating liquid which added the volatile solvent or water.

  The first resin composition coated in this manner can be cured by various methods, and examples thereof include hot air curing, induction overheating curing, and microwave curing. As the heat curing conditions, the heating temperature is, for example, 100 to 180 ° C, particularly 120 to 160 ° C, and the heating time is preferably 10 to 90 minutes, particularly 30 to 60 minutes. Moreover, the heating temperature at the time of heat-curing the applied second resin composition is, for example, 120 to 160 ° C., particularly 130 to 160 ° C., and the heating time is 20 to 60 minutes, particularly 30 to 60 minutes. Is preferred.

  Thus, the elastic roller 1 can be manufactured by forming the coat layer 4 including the end coat layer 4A and the center coat layer 4B on the outer peripheral surface of the elastic layer 3.

  The elastic roller 1 is provided with an end coat layer 4A containing boron nitride particles and a coat layer 4 having a central coat layer 4B on the outer peripheral surface of the elastic layer 3, so that the elastic roller 1 is mounted on an image forming apparatus or the like as an elastic roller. Since the time when the end coat layer is peeled off due to the outer diameter jumping can be adjusted, it is possible to determine the replacement time of the elastic roller according to the present invention.

  Further, since the elastic roller 1 has the end coat layer 4A that is relatively easily worn by containing boron nitride particles, even if the end coat layer 4A is worn and finally disappears, the elastic layer 3 and The central coat layer 4B is substantially free from wear and damage to the extent that the intended function is impaired. Therefore, the elastic roller 1 has a desired function by re-forming a new end coat layer 4A as described above on the outer peripheral surface of the elastic layer 3 on which the worn or disappeared end coat layer 4A has been formed. The elastic roller 1 can be regenerated. Therefore, the elastic roller 1 can reuse the shaft body 2, the elastic layer 3, and the central coat layer 4A even if the end coat layer 4A is peeled off or worn, thereby reducing the cost. realizable. As described above, according to the present invention, even if the end coat layer 4A is peeled off, the end coat layer 4A is regenerated so that at least the elastic layer, in addition to the shaft body and / or the central coat layer is reused. An elastic roller that can be provided can be provided.

  Next, a developing device (hereinafter sometimes referred to as a developing device or a developing cartridge according to the present invention) including the elastic roller 1 according to the present invention and an image forming device (hereinafter referred to as an image forming device according to the present invention). An example) will be described with reference to FIG. As shown in FIG. 3, the image forming apparatus 10 includes a plurality of image carriers 11B, 11C, 11M, and 11Y that are provided in the developing units B, C, M, and Y of each color in series on a transfer conveyance belt 6. Therefore, the developing units B, C, M, and Y are arranged in series on the transfer conveyance belt 6. The developing unit B includes an image carrier 11B such as a photosensitive member (also referred to as a photosensitive drum), a charging unit 12B such as a charging roller, an exposure unit 13B, a developing device 20B, and an image carrying belt 6. A transfer unit 14B that contacts the body 11B, such as a transfer roller, and a cleaning unit 15B are provided.

  The developing device 20B is an example of a developing device according to the present invention, and as shown in FIG. 3, an elastic roller according to the present invention as a developer carrier 23B, a developer 22B, for example, a positively charged developer, A developer seal member 25 (not shown in FIG. 3) that abuts against both ends of the developer carrier 23B and prevents developer leakage is provided. Therefore, in this image forming apparatus 10, the elastic roller 1 is mounted as a developer carrier 23B, 23C, 23M and 23Y, that is, as a developing roller. Specifically, the developing device 20B includes a housing 21B that houses a one-component non-magnetic developer 22B, a developer carrier 23B that supplies the developer 22B to the image carrier 11B, such as a developing roller, and a developer 22B. For example, a blade, and a developer seal member 25 (not shown in FIG. 3) that contacts both ends of the developer carrier 23B to prevent developer leakage. A developing device or a developing cartridge. In the developing device 20B, the contact state of the developer carrier 23B, the developer amount adjusting means 24B, and the developer seal member 25 is the contact of the elastic roller 1, the developer regulating member 24, and the developer seal member 25 shown in FIG. This is basically the same as the state, and the developer amount adjusting means 24B is in contact with or in pressure contact with the outer peripheral surface of the developer carrier 23B. That is, the developing device 20B is a so-called “contact developing device”. The developing units C, M and Y are basically configured in the same manner as the developing unit B.

  As the developer seal member 25 provided in the developing device 20B, as shown in FIG. 2, a known developer seal member having an arcuate sliding contact surface that contacts the outer peripheral surface of the elastic roller 1 can be used. For example, “end seal member 21” of Patent Document 1 can be cited. The developer seal member 25 has at least an arc-shaped slidable contact surface formed of an elastic member such as felt, and the arc-shaped slidable contact surface abuts on each outer peripheral region of the end coat layer 4A of the elastic roller 1 or It is attached or fixed to the developing device so as to be in pressure contact. Specifically, as shown in FIG. 2, the elastic roller 1 has an end coat layer in which the end side of each outer peripheral region of the end coat layer 4 </ b> A contacts the arcuate sliding surface of the developer seal member 25. The center side of each of 4A and the center coat layer 4B are attached to the developing device 20B so as to contact the developer regulating member 24 arranged in parallel with the developer seal member 25. Thus, the developer seal member 25 has an arcuate contact surface having substantially the same radius as the end coat layer 4A, and is fixed to the housing of the developing device 20B at the rear end (not shown). As the developer seal member 25, in addition to the “end seal member 21” in Patent Document 1, for example, “toner seal configuration” described in Japanese Patent Application Laid-Open No. 2007-140139, and Japanese Patent Application Laid-Open No. 2009-265574 are disclosed. The “side seal member” or the like can also be employed.

  In the image forming apparatus 10, the developer carrier 23B of the developing device 20B is disposed such that the surface thereof is in contact with or pressure contact with the surface of the image carrier 11B. Similarly to the developing device 20B, the developing devices 20C, 20M, and 20Y are arranged such that the surfaces of the developer carriers 23C, 23M, and 23Y are in contact with or pressed against the surfaces of the image carriers 11C, 11M, and 11Y. ing. That is, the image forming apparatus 10 is a so-called “contact image forming apparatus”.

  The fixing unit 30 is disposed on the downstream side of the developing unit Y. The fixing unit 30 includes a fixing roller 31, an endless belt support roller 33 disposed in the vicinity of the fixing roller 31, a fixing roller 31, and an endless belt support roller in a housing having an opening 35 through which the recording medium 16 passes. 33, an endless belt 36 wound around 33, and a pressure roller 32 disposed opposite to the fixing roller 31. The fixing roller 31 and the pressure roller 32 are in contact with or pressed against each other via the endless belt 36. It is a pressure heat fixing device which is supported in a freely rotatable manner. At the bottom of the image forming apparatus 10, a cassette 41 that houses the recording body 16 is installed. The transfer conveyance belt 6 is wound around a plurality of support rollers 42.

  Each of the developers 22B, 22C, 22M and 22Y used in the image forming apparatus 10 may be a dry developer or a wet developer as long as it can be charged by friction, and a non-magnetic developer or a magnetic developer. An agent may be used. One component non-magnetic black developer 22B, cyan developer 22C, magenta developer 22M and yellow developer 22Y are accommodated in the housings 21B, 21C, 21M and 21Y of the developing units. These developers 22B, 22C, 22M and 22Y are all positively charged developers in this example. Examples of the positively charged developer include a positively chargeable non-magnetic one-component polymer developer. Specifically, the positively charged developer is a binder resin obtained by polymerizing or copolymerizing acrylic monomers or styrene monomers such as acrylic acid, alkyl (meth) acrylate having 1 to 4 carbon atoms, This is a substantially spherical developer having developer particles composed of a colorant, a charge control agent and wax, and various external additives. Examples of the colorant include black, cyan, magenta, and yellow colorants. Examples of the charge control agent are copolymerizable with an ionic monomer having an ionic functional group such as an ammonium salt and an ionic monomer such as a styrene monomer or the acrylic monomer. Examples thereof include charge control resins obtained by copolymerization with monomers. Examples of the external additive include inorganic powders such as silica, aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide and other metal oxide powders, carbide powders, and metal salt powders. In order to positively charge the developer, the type and characteristics of the binder resin may be selected. If the binder resin is contained, the developer is positively charged.

  The shapes of the developers 22B, 22C, 22M and 22Y are all usually spherical, and their volume average particle diameter is 5 to 10 μm. The volume average particle diameter is a value measured by a measurement method using a pore electrical resistance method. For example, measurement can be performed using Beckman Coulter Coulter Multisizer II (aperture diameter 100 μm) or an equivalent device.

  The image forming apparatus 10 forms a color image on the recording body 16 as follows. First, in the developing unit B, an electrostatic latent image is formed by the exposure unit 13B on the surface of the image carrier 11B charged by the charging unit 12B, and the black electrostatic latent image is developed by the developer 22B supplied by the developer carrier 23B. The image is developed. The black electrostatic latent image is transferred to the surface of the recording medium 16B when the recording medium 16 passes between the transfer means 14B and the image carrier 11B. Next, in the same manner as in the developing unit B, a cyan image, a magenta image, and a yellow image are superimposed on the recording medium 16 in which the electrostatic latent image is visualized as a black image by the developing units C, M, and Y, respectively. A color image is visualized. Next, the recording body 16 in which the color image is visualized is fixed to the recording body 16 by the fixing unit 30 as a permanent image. In this way, a color image can be formed on the recording medium 16.

  In the tandem type image forming apparatus 10, when the elastic roller 1 according to the present invention is used as the developer carrying member 23, the developer leakage can be effectively prevented and an image such as the occurrence of fogging can be prevented regardless of the surrounding environment. The generation of image defects that affect quality can be substantially suppressed, the desired print density can be maintained over a long period of time, and the occurrence of uneven density in halftone images can also be prevented, resulting in high quality image quality. To make a great contribution. Further, the developing devices 20B, 20C, 20M, and 20Y all include the elastic roller 1 as the developer carrier 23. Therefore, according to the present invention, it is possible to provide an elastic roller and a developing device capable of achieving both high image quality and developer leakage, which are characteristics of image forming apparatuses that are opposite to each other, at a high level.

  Since the image forming apparatus 30 includes the elastic roller 1 having a coating layer containing boron nitride particles, the replacement timing of the elastic roller can be predicted according to the content of the boron nitride particles, and the exchanged use is performed. By forming the end coat layer on both ends of the finished elastic roller, the elastic roller having the original function can be reproduced, so that the elastic roller can be used semipermanently. Therefore, according to the present invention, it is possible to provide an image forming apparatus capable of predicting an appropriate replacement time of the elastic roller and efficiently using the elastic roller.

  The elastic roller, the developing device, and the image forming apparatus according to the present invention are not limited to the above-described embodiments, and various modifications can be made within a range in which the object of the present invention can be achieved. For example, the elastic roller 1 includes the coat layer 4 having the end coat layer 4A and the center coat layer 4B. In this invention, the elastic roller only needs to include the end coat layer. May not be provided.

Example 1
An electroless nickel-plated shaft body (SUM22, diameter 10 mm, length 275 mm) was washed with ethanol, and a silicone primer (trade name “Primer No. 16”, manufactured by Shin-Etsu Chemical Co., Ltd.) on its surface. ) Was applied. The shaft body subjected to the primer treatment was fired at a temperature of 150 ° C. for 10 minutes using a gear oven, and then cooled at room temperature for 30 minutes or more to form a primer layer on the surface of the shaft body.

Next, 100 parts by mass of dimethylpolysiloxane (D) (degree of polymerization 300) blocked at both ends with dimethylvinylsiloxy groups, and hydrophobized fumed silica having a BET specific surface area of 110 m ² / g (Nippon Aerosil Co., Ltd.) Made by company, R-972) 1 part by mass, average particle size 6 μm, bulk density of 0.25 g / cm ³ diatomaceous earth (F) (Oplite W-3005S, manufactured by Hokuaki Diatomite Co., Ltd.) 40 parts by mass, and 5 parts by mass of acetylene black (G) (Denka Black HS-100, manufactured by Denki Kagaku Kogyo Co., Ltd.) was placed in a planetary mixer, stirred for 30 minutes, and then passed once through three rolls. This is returned to the planetary mixer again, and as a crosslinking agent, methyl hydrogen polysiloxane (E) having Si—H groups at both ends and side chains (polymerization degree 17, Si—H amount 0.0060 mol / g) 2. 1 part by mass, 0.1 part by mass of ethynylcyclohexanol as a reaction control agent and 0.1 part of platinum catalyst (H) (Pt concentration 1%) are added, and the mixture is stirred and kneaded for 15 minutes to be an addition curing type. A liquid conductive silicone rubber composition was prepared. The prepared addition-curable liquid conductive silicone rubber composition was molded on the outer peripheral surface of the shaft body 2 by liquid injection molding. In liquid injection molding, the addition-curable liquid conductive silicone rubber composition was cured by heating at 150 ° C. for 10 minutes. This molded body was polished to form an elastic layer 3 having an outer diameter of 20 mm. The elastic layer 3 had a JIS A hardness of 40, and both volume resistivity and electrical resistivity were within the above ranges.

As the first resin composition capable of forming the end coat layer 4A, “TW-825” (manufactured by Henkel Japan Co., Ltd.) having mainly the following composition was prepared.
-35 parts by mass of a resin obtained by reacting polyol and γ-glycidoxypropyltrimethoxysilane (mixing ratio at the time of reaction is 30 parts by mass of polyol and 5 parts by mass of γ-glycidoxypropyltrimethoxysilane)
Boron nitride particles (average particle size 10 μm) 8 parts by mass (23 parts by mass with respect to 100 parts by mass of the resin)
・ 50 parts by mass of pure water

A second resin composition capable of forming the center coat layer 4B was prepared.
-Polyisocyanate (hexamethylene diisocyanate) 14 parts by mass- Condensed polyester polyol (mixing molar ratio of 1,6-hexanediol and adipic acid [COOH / OH] = 12/13) 28 parts by mass (said isocyanate and polyester polyol (NCO / OH] = 1.1 / 1)
-Carbon black (trade name “Toka Black # 4500”, manufactured by Tokai Carbon Co., Ltd.) 3 parts by mass (particle size 40 nm, 7.1 parts by mass with respect to 100 parts by mass of urethane adjusting component) as a conductivity imparting agent
・ 0.03 parts by mass of dibutyltin dilaurate (trade name “di-n-butyltin dilaurate”, manufactured by Showa Chemical Co., Ltd.) ・ silica (trade name “ACEMATT OK-607”, manufactured by Degussa, average particle as filler particles 1.5 μm in diameter) 4 parts by mass (9.5 parts by mass with respect to 100 parts by mass of the urethane adjusting component)

  The outer peripheral surface other than the outer peripheral surface up to 6 mm from each edge of the elastic layer 3 to the center side is subjected to masking treatment, and the prepared second resin composition is applied to the outer peripheral surface of the elastic layer 3 by a spray coating method. The film was heated at 160 ° C. for 30 minutes to form a central coat layer 4B having a layer thickness of 20 μm. Next, the outer peripheral surface of the central coat layer 4B is subjected to masking treatment, and the prepared first resin composition is applied to the outer peripheral surface of the elastic layer 3 by a spray coating method and heated at 160 ° C. for 30 minutes to have a layer thickness of 10 μm. An end coat layer 4A was formed. Thus, the elastic roller of Example 1 was manufactured.

(Example 2)
The elastic rollers of Example 2 were manufactured in substantially the same manner as in Example 1 except that the boron nitride particles were changed to 4 parts by mass (11.5 parts by mass with respect to 100 parts by mass of the resin).

(Example 3)
The elastic rollers of Example 3 were manufactured in substantially the same manner as in Example 1 except that the boron nitride particles were changed to 0.5 parts by mass (1.4 parts by mass with respect to 100 parts by mass of the resin). did.

(Comparative Example 1)
In place of the “TW-825” (manufactured by Henkel Japan Co., Ltd.), the elastic roller of Comparative Example 1 was basically the same as Example 1 except that the first resin composition mainly having the following composition was used. Manufactured.
48 parts by mass of a resin obtained by reacting polyol with γ-glycidoxypropyltrimethoxysilane (mixing ratio during reaction is 43 parts by mass of polyol and 5 parts by mass of γ-glycidoxypropyltrimethoxysilane)
・ 12 parts by mass of fluororesin (PTFE) particles (particle size: 1 μm) (25 parts by mass with respect to 100 parts by mass of the resin)
・ 40 parts by mass of pure water

(Comparative Example 2)
A comparison was basically made in the same manner as in Example 1 except that “Emralon 345 Black” (manufactured by Henkel Japan) having mainly the following composition was used instead of “TW-825” (manufactured by Henkel Japan). The elastic roller of Example 2 was manufactured.
48 parts by mass of a resin obtained by reacting polyol with γ-glycidoxypropyltrimethoxysilane (mixing ratio during reaction is 43 parts by mass of polyol and 5 parts by mass of γ-glycidoxypropyltrimethoxysilane)
・ 12 parts by mass of fluororesin (PTFE) particles (particle size: 1 μm) (25 parts by mass with respect to 100 parts by mass of the resin)
-3 parts by mass of carbon black as a conductivity-imparting agent (particle size 0.7 μm, 6 parts by mass with respect to 100 parts by mass of the resin)
・ 40 parts by mass of pure water

(Judgment of replacement time)
A simple rotating device having the following structure was produced. Specifically, a large-diameter roller made of SUM22 having an outer diameter of 55 mm and a surface state of Rz 30 μm as an image carrier, and a roller mounting portion that presses the test roller uniformly in the axial direction with a pressure of 1 N against the large-diameter roller And a driving device for rotating the large-diameter roller. Each elastic roller manufactured in the example and the comparative example was mounted on the roller mounting portion, and the large-diameter roller was rotated 5000 times at a rotation speed of 1000 rotations / minute in an environment of a temperature of 23 ° C. and a relative humidity of 50 RH%. After the rotation speed of the large-diameter roller exceeded 1000 times, the rotation was stopped every 1000 rotations, and the state of the end coat layer of the elastic roller mounted was observed.

  As a result, it was confirmed that each of the elastic rollers of Examples 1 to 3 peeled off at the end coat layer at 3000 to 6000 rotations corresponding to the set number of prints. On the other hand, it was confirmed that the end coat layer was peeled off at 12,000 revolutions for the elastic roller of Comparative Example 1 and 10,000 revolutions for the elastic roller of Comparative Example 2. When the elastic roller is attached to the image forming apparatus, when the end coat layer is peeled in this way, it is possible to know the replacement timing of the elastic roller with reference to the time when the set number of prints are completed.

DESCRIPTION OF SYMBOLS 1 Elastic roller 2 Shaft body 3 Elastic layer 4 Coat layer 4A End part coat layer 4B Center coat layer 4C Center side edge part 10 Image forming apparatus 11B, 11C, 11M, 11Y Image carrier 12B, 12C, 12M, 12Y Charging means 13B , 13C, 13M, 13Y Exposure means 14B, 14C, 14M, 14Y Transfer means 15B, 15C, 15M, 15Y Cleaning means 16 Recording body 20 Developing devices 21B, 21C, 21M, 21Y, 34 Housings 22B, 22C, 22M, 22Y Developer 23B, 23C, 23M, 23Y Developer carrier 24, 24B, 24C, 24M, 24Y Developer regulating member 25 Developer seal member 30 Fixing means 31 Fixing roller 32 Pressure roller 33 Endless belt support roller 35 Opening 36 Endless belt 41 Cassette 42 Support rollers B, C, M, Y Development unit

Claims (3)

  A shaft, an elastic layer formed on the outer peripheral surface of the shaft, and an outer surface of the elastic layer that reacts with a polyol and a silane coupling agent formed on both ends in the axial direction of the elastic layer An elastic roller comprising an end coat layer containing a resin and boron nitride particles.   A developing device comprising the elastic roller according to claim 1.   An image forming apparatus comprising the developing device according to claim 2.

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