JP2006162684A - Conductive roller manufacturing method and conductive roller manufactured by this method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive roller manufacturing method capable of forming a coating layer of a highly accurate film-thickness on the periphery of a substrate without contaminating a coating material, and to provide a conductive roller formed by the method. <P>SOLUTION: A ultra die 11 has a slit-like opening 12 shorter than the length of the substrate 6 and is disposed such that the opening 12 is parallel to the substrate 6 and opposite the peripheral face of the substrate 6. While the coating material having a predetermined flow rate is supplied to the ultra die 11, and the substrate 6 is rotated, at least either the ultra die 11 or substrate 6 is displaced one relative to the other in the direction of the length of the substrate. The coating material supplied to the ultra die 11 is applied to the peripheral face of the substrate 6 from the opening 12 as it is, thereby forming the coating layer 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a conductive roller used in an electrophotographic apparatus such as a copying machine and a printer, and an image forming apparatus such as an electrostatic recording apparatus, and a conductive roller formed by this method. It is related with what can apply | coat and can form a coating layer in high quality.

  Conductive rollers such as a charging roller that is mounted on an image forming apparatus such as an electrophotographic apparatus such as a copying machine or a printer or an electrostatic recording apparatus and charges the surface of the photosensitive drum, and a developing roller that transfers toner onto the surface of the photosensitive drum Has a base layer disposed around a shaft portion pivotally supported at both ends in the length direction, and one or more coating layers provided on the radially outer side of the base layer.

Conventionally, as a method of forming this coating layer, dipping coating is mainly used (see, for example, Patent Document 1). This method uses a layer inside the coating layer to be formed as a base portion, and the base portion is vertically aligned. Then, it is immersed in a dip tank containing the paint, and then a coating layer having a required film thickness is formed by pulling up at a predetermined speed, and a thick film can be formed by a single immersion, It has the feature that a large amount of conductive rollers can be processed at once by enlarging the dip tank.
JP 2003-131474 A

  However, the method of forming the coating layer by dipping coating, even if the speed of pulling up the base portion can be kept constant, the film thickness depends greatly on the environmental conditions and the viscosity of the paint. Is increased, it is difficult to keep the viscosity of the paint contained therein constant, which has been a factor in reducing the film thickness accuracy.

  Further, since the dip tank is open to the atmosphere, there is also a problem that the paint is contaminated when foreign substances are mixed in the paint and used for a long time.

  The present invention has been made in view of such problems, and a method for manufacturing a conductive roller, which can form a coating layer having a highly accurate film thickness without contaminating the paint, and this method. It is an object of the present invention to provide a conductive roller formed by the above.

<1> is a method in which at least one coating layer of a conductive roller having a base layer disposed around the shaft portion and one or more coating layers provided on the outer side in the radial direction of the base layer is provided inside the coating layer. In the manufacturing method of the conductive roller formed by applying a paint to the peripheral surface of the base portion composed of layers,
While supplying a paint at a predetermined flow rate to an ultra die having a slit-like opening shorter than the length of the base portion and facing the peripheral surface of the base portion in a direction parallel to the base portion. While rotating the base portion, at least one of the ultra die and the base portion is relatively displaced in the base portion length direction with respect to the other, and the paint supplied to the ultra die is applied from the opening to the peripheral surface of the base portion. It is a manufacturing method of the conductive roller which forms a coating layer by applying.

  <2> is set such that, in <1>, the displacement speed at which at least one of the ultra die and the base portion is relatively displaced is relatively displaced by a distance shorter than the length of the opening while the conductive roller rotates once. This is a method for manufacturing a conductive roller.

  <3> is a method for producing a conductive roller in which the thickness of the coating layer is controlled by changing the flow rate of the paint supplied to the ultra die in <1> or <2>.

  <4> is a method for producing a conductive roller according to any one of <1> to <3>, wherein the paint has a viscosity at 25 ° C. of 200 to 100,000 mPa · S.

  <5> is a conductive roller that uses an electron beam curable resin or an ultraviolet curable resin containing an ultraviolet polymerization initiator in any one of <1> to <5> as the paint. It is a manufacturing method.

  <6> is a method for producing a conductive roller in which a paint containing particles having an average particle diameter of 1 to 30 μm is supplied to an ultra die in any one of <1> to <5>.

  <7> is composed of a shaft portion pivotally supported at both ends in the length direction, a base layer disposed around the shaft portion, and one or more coating layers covering a radially outer side of the base layer. In any one of <1> to <6>, the layer is a conductive roller formed by a method for manufacturing a conductive roller.

  According to the invention of <1>, since it is applied using an ultra die, it is difficult to control the film thickness when a coating layer is formed by dip coating. By controlling the amount of paint supplied to the ultra die, it is possible to accurately control the amount of paint discharged from the slit-shaped opening and applied to the peripheral surface of the base portion. It is possible to make it highly accurate, and the paint supplied to the ultra die is applied as it is from the opening to the peripheral surface of the base, so that the paint is not released to the atmosphere. Thus, contamination of the paint can be prevented.

  According to the invention of <2>, the displacement speed when the at least one of the ultra die and the base portion is relatively displaced is set so as to be relatively displaced by a distance shorter than the length of the opening while the conductive roller rotates once. Therefore, the thickness of the strip of the coating film discharged from the ultra die and formed in a spiral shape on the peripheral surface of the base portion can be regulated by the opening portion one or more times, and the coating layer film The thickness can be made more uniform.

  According to the invention <3>, since the thickness of the coating layer is controlled by changing at least one of the flow rate of the coating material supplied to the ultra die and the gap between the substrate and the opening, the conductive roller The film thickness of the coating layer that changes according to the size of the coating can be changed easily and in a short time without reducing its accuracy, thereby shortening the time for size switching in high-mix low-volume production it can.

  According to the invention of <4>, since a paint having a viscosity at 25 ° C. of 200 to 100,000 mPa · S is used as the paint, the foam in which the base portion has dispersed void cells by the action of the paint having a high viscosity and hardly flowing When the base layer is formed, the coating layer can be smoothly formed without filling the void cells exposed on the surface of the base portion with the coating layer, while the base portion is made of a non-foamed body having no void cells. Even in this case, it is possible to prevent the paint from flowing due to gravity and changing the coating thickness.

  According to the invention <5>, since an electron beam curable resin or an ultraviolet curable resin containing an ultraviolet polymerization initiator is used, the base layer is made of a foam in which void cells are dispersed. In such a case, the coating layer coated with the coating layer can be instantly cured by electron beam curing or ultraviolet curing so that the void cells exposed on the surface of the substrate portion are not filled with the coating layer. The surface can be made smooth. On the other hand, even when the base portion is made of a non-foamed body without void cells, the coating is instantaneously cured to prevent the coating from flowing due to gravity and changing the coating thickness. it can.

  According to the invention of <6>, since the paint containing particles having an average particle diameter of 1 to 30 μm is supplied to the ultra die, the base material can be used without changing the particle size distribution of the paint supplied to the ultra die. It can be reliably applied as a coating layer on the periphery of the portion, and a desired surface roughness can be imparted to the conductive roller by controlling the particle size distribution of the particles in the paint.

  According to the invention of <7>, the shaft portion that is pivotally supported at both ends in the length direction, the base layer disposed around the shaft portion, and one or more coating layers covering the radially outer side of the base layer, Since at least one coating layer is formed by the above-described method, the coating layer has a highly accurate film thickness and is formed of a contamination-free material. Alternatively, in the case of a charging roller, it can carry a uniform developing performance or charging performance, and can be used for a high-quality image forming apparatus.

The embodiment of the present invention will be described in more detail.
FIG. 1 is a cross-sectional view showing a conductive roller according to the present invention, FIG. 1 (a) shows a first embodiment thereof, and the conductive roller 1 includes a shaft portion 2 supported at both ends in the length direction, and The base layer 3 disposed around the shaft portion 2 and the coating layer 4 covering the peripheral surface of the base layer 3, and the shaft portion 2 is made of metal such as iron or stainless steel or plastic, and the base layer 3. Is provided so as to protrude outward in the longitudinal direction, and the protruding portion is configured to be supported by a roller shaft supporting means of the image forming apparatus.

  FIG. 1B is a cross-sectional view showing a second embodiment of the conductive roller. The conductive roller 1A is composed of a shaft portion 2A, a base layer 3, and a coating layer 4, and a shaft portion 2A instead of the shaft portion 2 is shown. Unlike the first embodiment, the shaft portion 2A is made of a hollow pipe made of a metal such as iron or stainless steel or plastic, and the cross-sectional area of the base layer 3 is kept small with the same outer diameter. In this case, it is possible to make the conductive roller lightweight by suitably using such a hollow shaft portion 2A.

  Further, the shaft portion 2A can be protruded outward in the length direction of the base layer 3 so that the radially outer side is supported in the same manner as the shaft portion 2, but as shown in FIG. The inner surface in the radial direction of the pipe may be pivotally supported. In this case, the shaft portion 2A does not need to protrude outward in the length direction of the base layer 3.

  The example shown in FIGS. 1A and 1B is a case where the conductive roller 1 has a single coating layer 4, but may have a plurality of coating layers 4, and in this case, at least the coating layer One layer should just be formed by the method mentioned later.

  As the base layer 3, a material obtained by adding a conductive agent to a single elastomer or a foam obtained by foaming it is used. The elastomer that can be used here is not particularly limited, and nitrile rubber, ethylene-propylene rubber, styrene-butadiene rubber, butadiene rubber, isoprene rubber, natural rubber, silicone rubber, urethane rubber, acrylic rubber, chloroprene rubber, butyl rubber, An epichlorohydrin rubber etc. are illustrated and these can be used individually or in combination of 2 or more types. Of these, ethylene-propylene rubber, butadiene rubber, silicone rubber, and urethane rubber are preferably used in the present invention. A mixture of these and other rubber materials is also preferably used. In particular, in the present invention, a resin having a urethane bond is preferably used.

  Further, it is also possible to use a foamed product obtained by chemically foaming these elastomers using a foaming agent, or by foaming by mechanically entraining air like polyurethane foam. In the present invention, a so-called RIM molding method may be used in a molding process for integrating the shaft portion 2 and the base layer 3. That is, two types of monomer components constituting the raw material components of the base layer 3 are mixed and injected into a cylindrical mold and polymerized to integrate the shaft portion 2 and the base layer 3. In this method, the molding process from the injection of the raw material to the demolding can be performed in a required time of about 60 seconds, and the production cost can be greatly reduced.

  Various conductive agents can be used as the conductive agent added to the base layer 3. The carbon-based conductive agent can obtain high conductivity with a small amount of addition, and as the carbon-based conductive agent, ketjen black or acetylene black is preferably used, but SAF, ISAF, HAF, FEF, GPF, SRF, Carbon black for rubber such as FT and MT, carbon black for ink such as oxidized carbon black, pyrolytic carbon black, graphite and the like can also be used.

  Examples of ionic conductive agents include dodecyltrimethylammonium such as tetraethylammonium, tetrabutylammonium and lauryltrimethylammonium, octadecyltrimethylammonium such as hexadecyltrimethylammonium and stearyltrimethylammonium, ammonium such as benzyltrimethylammonium and modified aliphatic dimethylethylammonium. Organic ionic conducting agents such as perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, alkylsulfate, carboxylate, sulfonate; Perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, trifluoromethyl sulfate, sulfate of alkali metal or alkaline earth metal such as sodium, calcium, magnesium It can be exemplified inorganic ion conductive agent such as phosphate salts.

  Electronic conductive agents other than carbon-based ones can also be used. Examples of such electronic conductive agents include fine particles of metal oxides such as ITO, tin oxide, titanium oxide, and zinc oxide; nickel, copper, silver, germanium, and the like. Examples thereof include metal oxides; conductive titanium oxide whiskers, transparent whiskers such as conductive barium titanate whiskers; and the like.

  Two or more kinds of conductive agents may be used as a mixture, and in this case, the conductivity can be stably exhibited even when the applied voltage varies or the environment changes. As an example of mixing, a carbon-based conductive agent mixed with an electronic conductive agent other than a carbon-based conductive agent or an ionic conductive agent can be used.

  For example, when the conductive roller 1 is a charging roller, the coating layer 4 is made of nylon, polyester, urethane-modified acrylic resin, phenol resin, acrylic resin, epoxy resin, urethane resin, urea resin, fluorine resin. However, a fluororesin is preferably used from the viewpoint of the surface smoothness of the charging roller and the low adhesion to the photosensitive member.

  Examples of fluororesins include polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-ethylene copolymer, polychlorotriethylene. Fluoroethylene, chlorotrifluoroethylene-ethylene copolymer, polyvinylidene fluoride, polyvinyl fluoride, chlorotrifluoroethylene-vinyl ether copolymer, tetrafluoroethylene-vinylidene fluoride copolymer, chlorotrifluoroethylene- And vinyl ester copolymers, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymers, etc. Dispersion type water-based fluororesin is preferably used dispersed in, more preferably dispersion type water-based fluorine resin dispersed with fine particles of polytetrafluoroethylene in water is used. The particle size of the fluororesin fine particles used is not particularly limited, but is preferably 5 μm or less, and particularly preferably 0.05 to 1 μm.

  Also, the coating layer 4 can be formed by mixing these fluororesins with other resins within a range not impairing the effects of the fluororesin. In this case, other resins mixed with the fluororesin include polyvinyl acetal resin, urethane resin, polyester resin, acrylic resin, nylon resin, epoxy resin, vinylidene chloride copolymer, acrylic-urethane copolymer, and the like. The coating layer 4 can be formed by mixing one or more of these with the fluororesin. Among these resins, a polyvinyl acetal resin, a urethane resin, a polyester resin, and a vinylidene chloride copolymer are preferable from the viewpoints of forming a coating film of a fluororesin and uniformity of resistance, and a polyvinyl acetal resin is particularly preferable.

  Moreover, in the coating layer 4, when it is desired to ensure the smoothness, an aqueous resin is preferably used. The water-based resin may be any type such as a water-soluble type, an emulsion type, and a suspension type as long as the solvent is water, but in particular, an acrylic hot water-soluble resin having active hydrogen such as a carboxyl group, a hydroxyl group, and an amino group. Is preferred. Acrylic resin has a much lower dielectric constant than urethane and nylon, which have been generally used as charging roller resins, and has a smaller electrostatic capacity. The electric attractive force / repulsive force is reduced, and the charging noise can be reduced.

  Furthermore, an appropriate amount of an appropriate additive such as a thickener, thixotropic property imparting agent, structural viscosity imparting agent or the like can be added to the coating layer 4 as necessary. In this case, the additive is inorganic. Either an organic type or an organic type may be used.

  When the conductive roller 1 is a developing roller, a crosslinkable resin is preferably used as the resin constituting the coating layer 4. The crosslinkable resin refers to a resin that self-crosslinks with heat, catalyst, air (oxygen), moisture (water), electron beam, or the like, or a resin that crosslinks by reaction with a crosslinking agent or other crosslinkable resin. Examples of such crosslinkable resins include hydroxyl groups, carboxyl groups, acid anhydride groups, amino groups, imino groups, isocyanate groups, methylol groups, alkoxymethyl groups, aldehyde groups, mercapto groups, epoxy groups, unsaturated groups, etc. Fluorine resin, polyamide resin, acrylic urethane resin, alkyd resin, phenol resin, melamine resin, silicone resin, urethane resin, polyester resin, polyvinyl acetal resin, epoxy resin, polyether resin, amino resin, acrylic resin, Mention may be made of urea resins and the like and mixtures thereof. Of these, fluorine resins, polyamide resins, acrylic urethane resins, alkyd resins, phenol resins, melamine resins, silicone resins, urethane resins, polyester resins, polyvinyl acetal resins, epoxy resins, and mixtures thereof are preferred, and alkyd resins are particularly preferred. , Phenol resin, melamine resin and mixtures thereof are preferable from the viewpoint of charging ability of the developer, non-contamination to the developer, reduction of frictional force with other members, non-contamination to the image forming body, and the like.

  For the crosslinkable resin, a catalyst and a crosslinking agent are used as necessary. Examples of the catalyst include radical catalysts such as peroxides and azo compounds, acid catalysts, basic catalysts, and the like. In addition, the crosslinking agent has one molecule of reactive group such as hydroxyl group, carboxyl group, acid anhydride group, amino group, imino group, isocyanate group, methylol group, alkoxymethyl group, aldehyde group, mercapto group, epoxy group, and unsaturated group. Examples thereof include compounds having two or more compounds, for example, polyol compounds, polyisocyanate compounds, polyaldehyde compounds, polyamine compounds, polyepoxy compounds and the like. This crosslinkable resin can be further charged with a charge control agent, lubricant, conductive agent, other resin, etc. as desired for the purpose of further improving the charging ability to the developer, reducing the frictional force with other members, and imparting conductivity. Various additives can be contained.

  Among the above-mentioned resins, those containing an electron beam curable resin or an ultraviolet curable resin are preferable in that a drying step is not required after the coating layer 4 is applied. These resins are irradiated with an electron beam, Alternatively, it can be cured by irradiating with ultraviolet rays in the presence of an ultraviolet polymerization initiator.

  As electron beam curable resin or ultraviolet curable resin, polyester resin, polyether resin, fluorine resin, epoxy resin, amino resin, polyamide resin, acrylic resin, acrylic urethane resin, urethane resin, alkyd resin, phenol resin, melamine resin, A urea resin, a silicone resin, a polyvinyl butyral resin, etc. are mentioned, These 1 type (s) or 2 or more types can be mixed and used.

  Furthermore, modified resins in which specific functional groups are introduced into these resins can also be used. Further, in order to improve the mechanical strength and environmental resistance characteristics of the resin layer 4, it is preferable to introduce one having a crosslinked structure.

  Among the above-mentioned electron beam curable resins or ultraviolet curable resins, a composition formed from a (meth) acrylate ultraviolet curable resin containing a (meth) acrylate oligomer is particularly suitable.

  Examples of such (meth) acrylate oligomers include urethane (meth) acrylate oligomers, epoxy (meth) acrylate oligomers, ether (meth) acrylate oligomers, ester (meth) acrylate oligomers, and polycarbonate (meth). Examples include acrylate oligomers, and fluorine-based and silicone-based (meth) acrylic oligomers.

  The (meth) acrylate oligomer is composed of a compound such as polyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, bisphenol A type epoxy resin, phenol novolac type epoxy resin, adduct of polyhydric alcohol and ε-caprolactone, It can be synthesized by reaction with (meth) acrylic acid or by urethanizing a polyisocyanate compound and a (meth) acrylate compound having a hydroxyl group.

  The urethane-based (meth) acrylate oligomer can be obtained by urethanizing a polyol, an isocyanate compound and a (meth) acrylate compound having a hydroxyl group.

  Examples of the epoxy-based (meth) acrylate oligomer may be any reaction product of a compound having a glycidyl group and (meth) acrylic acid. Among them, a benzene ring, a naphthalene ring, a spiro ring, a dicyclopentadiene, A reaction product of a compound having a cyclic structure such as tricyclodecane and having a glycidyl group and (meth) acrylic acid is preferred.

  Furthermore, ether-based (meth) acrylate oligomers, ester-based (meth) acrylate oligomers and polycarbonate-based (meth) acrylate oligomers react with polyols (polyether polyols, polyester polyols and polycarbonate polyols) and (meth) acrylic acid, respectively. Can be obtained by:

  A reactive diluent having a polymerizable double bond is blended in the electron beam curable resin composition or the ultraviolet curable resin composition as necessary to adjust the viscosity. As such a reactive diluent, for example, a monofunctional, difunctional or polyfunctional polymerizable compound having a structure in which (meth) acrylic acid is bonded to a compound containing an amino acid or a hydroxyl group by an esterification reaction or an amidation reaction Etc. can be used. These diluents are usually preferably used in an amount of 10 to 200 parts by weight per 100 parts by weight of the (meth) acrylate oligomer.

  The resin constituting the coating layer 4 is mixed with a conductive agent for the purpose of controlling its conductivity. As the conductive material, the same conductive agent contained in the base layer 3 as described above should be used. Can do.

  Next, a method of forming the coating layer 4 as described above by applying a paint to the outside of the base portion 6 including one or more layers including the base layer 3 will be described with reference to FIGS. . 2 is a plan view showing an apparatus for applying a coating material, FIG. 3 is a cross-sectional view showing a cross section corresponding to the arrow AA in FIG. 2, and the applying apparatus 20 is a roller for rotating the conductive roller 1. The roller rotating device 21 includes a rotating device 21 and a die coater 10 that applies paint to the peripheral surface of the base portion 6. The roller rotating device 21 includes a support member 23 that supports the base portion 6 at both ends in the length direction, and a base. The motor 24 rotates the part 6 at a predetermined number of revolutions, and a fixed base 25 on which the support member 23 and the motor 24 are mounted.

  The die coater 10 has a slit-shaped opening 12, supports an ultra die 11 that discharges and applies paint to the peripheral surface of the base 6 from the opening 12, and supports the ultra die 11. A guide part 13 for guiding the separation approaching operation to 6, a moving base 14 on which the guide part 13 is mounted, and a motor 14 for moving the moving base 14 in the longitudinal direction of the base part 6 via the ball screw 16. The traverse guide 15 for guiding the transverse displacement of the moving base 14 and the paint supply device 40 for supplying the paint to the ultra die 11 are configured. The ultra die 11 and the paint supply device 40 are provided with a pipe 29 for supplying the paint. Connected with

  In the apparatus 20 shown in FIG. 2, the die coater 10 is configured to reciprocate. Alternatively, the roller rotating device 21 may be reciprocated in the length direction of the conductive roller 1. Alternatively, both may be displaced from each other.

  Here, the ultra die 11 faces the peripheral surface of the base body 6 with a predetermined interval at a position where the opening 12 is parallel to the length direction of the base body 6 and is close to the base body 6. The length of the opening 12 is set shorter than the effective image forming range of the base 6. When the coating layer 4 is formed by applying the base portions 6 having different lengths, the base portion 6 can be dealt with only by changing the stroke when the moving base 14 is displaced transversely. Switching between sizes can be easily performed.

  FIG. 4 is a conceptual diagram showing the configuration of the paint supply device 40. The paint supply device 40 includes a storage tank 44 that contains the paint, and a paint pump that sucks the paint from the storage tank 44 and pumps the paint to the ultra die 11. 41 and a filter 42 that removes foreign matters and the like contained in the pumped paint, and the paint pump 41 is operated by rotating the impeller by a motor 43.

  In addition, the coating device 20 includes a control device 50, and the control device 50 performs control to rotate the motor 24 that rotationally drives the base portion 6 at a constant speed, and also drives the motor 14 that drives the transverse displacement of the ultra die 11. The motor 33 that operates the paint pump is controlled to be synchronized with the rotation of the motor 24. In the figure, 45 is a pressure gauge for monitoring the pressure of the paint, and 46 is a bypass valve for maintenance or the like.

FIG. 5 is an external view of the conductive roller showing a state in the middle of applying the paint to the base portion 6, and when the coating device 20 configured as described above is operated, the peripheral surface of the base portion 6 is applied. The film band 31 is formed in a spiral shape, and the helical pitch P (m) is determined by changing the feed speed v (m / s) in the roller length direction of the base portion 6 to the rotational speed ω ( s ⁻¹ ), and by reducing the helical pitch P from the length of the opening 12, that is, the width W of the coating strip 31, the thickness of the coating film once formed can be reduced. It is possible to perform layer formation while restricting again, and the thickness of the coating layer 4 can be made very uniform. In this respect, the pitch P is preferably small, but on the other hand, if the pitch P is small Since production efficiency decreases, it is important to set the pitch P to satisfy both of these requirements. The

  Here, as the coating material applied on the base portion 6, it is possible to use a resin prepared by dissolving the resin exemplified above as the resin constituting the coating layer 4 in a solvent or preparing it without a solvent.

  When using a solvent, examples of the solvent used for preparing the coating liquid include alcohol solvents such as methanol, ethanol, isopropanol and butanol, ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, and aromatic solvents such as toluene and xylene. Hydrocarbon solvents, aliphatic hydrocarbon solvents such as hexane, alicyclic hydrocarbon solvents such as cyclohexane, ester solvents such as ethyl acetate, ether solvents such as isopropyl ether and tetrahydrofuran, amide systems such as dimethylformamide Examples include solvents, halogenated hydrocarbon solvents such as chloroform and cycloethane, water-based paints such as acrylic paints, and mixed solvents thereof.

  The method of the present invention for forming the coating layer 4 of the conductive roller 1 using the die coater 10 is a particularly effective method when using a paint having a viscosity of 200 to 100,000 mPa · S at 25 ° C. In the method of forming the coating layer 4 by the above method, it is difficult to atomize such a high-viscosity paint. On the other hand, when the paint contained in the dip tank is immersed, the viscosity is too high and the film thickness is too high. It is extremely thick and difficult to realize.

  The advantage of using such a high-viscosity paint is that the paint is difficult to flow, so that the base portion 6 disperses the void cells 34 as shown in a sectional view of the vicinity of the base portion surface in FIG. In the case of the base layer 33 made of foam, the base layer 33 can be smoothly coated by forming the coating layer 36 having a uniform thickness without filling the void cells 34 s exposed on the surface of the base layer 33 with the coating layer 36. If the viscosity of the paint is low, as shown in FIG. 5 (b) corresponding to FIG. 5 (a), the coating is formed by flowing into the void cell 34s exposed on the surface. The layer 36A is formed, and the elastic characteristics that the base layer 33 should have and the conductive characteristics that the covering layer 36 should provide cannot be made desirable, and these characteristics become non-uniform. .

  Further, even when the base portion 6 is made of a non-foamed material, the viscosity is high, so that the flow due to gravity can be suppressed and the dimensional change until curing can be suppressed. Can contribute to the formation.

  Similarly, when the coating layer 4 is formed using a paint containing an ultraviolet curable resin or an electron beam curable resin, the coating layer 4 is instantly cured immediately after coating, thereby suppressing the flow and increasing the viscosity. The same effect can be brought about. In the first place, the paint containing the ultraviolet curable resin or the electron beam curable resin is used in order to eliminate the large drying equipment required if this is a thermosetting resin. Therefore, in the case of using a paint containing an ultraviolet curable resin or an electron beam curable resin, an extremely low amount of solvent is used. In such a case, for the same reason, a die coater type A coating method can be suitably used.

  Moreover, the method of forming the coating layer 4 using the die coater 10 is such that when the coating layer 4 is a layer in which particles are dispersed, the coating material supplied to the ultra die 11 has a particle size distribution on the entrance side. Since it is discharged from the opening portion 12 while being maintained, it can be advantageously used, and the particle size distribution of the coating layer 4 becomes uniform, whereby the coating layer 4 having a uniform surface roughness can be formed.

  For example, when the conductive roller is a developing roller, the particles contribute to enhancing the performance of charging the toner, and a preferable surface roughness Ra is 0.5 to 1.5 μm. In this case, as the particles for supporting the surface roughness, inorganic fine particles such as rubber or synthetic resin fine particles, carbon fine particles and silica-based fine particles are preferable. Silicone rubber, silicone resin, fluororesin, urethane Elastomers, polyolefin resins, epoxy resins, polystyrene resins, urethane acrylates, melamine resins, phenol resins, (meth) acrylic resins, glassy carbon particles and silica particles are particularly preferable. These fine particles may be used alone or in combination of two or more.

  As the charging roller or developing roller, the conductive rollers of Examples 1 to 8 and Comparative Examples 1 and 2 were prepared according to the procedure described below, and the characteristics of these rollers were evaluated. Images when incorporated in an image forming apparatus were evaluated. Table 1 summarizes the main specifications and evaluation results in the production of the conductive roller for these examples and comparative examples.

Example 1
After adding 1.6 parts of conductive carbon and 0.15 parts of dibutyltin dilaurate to 100 parts by weight of tri-functional 9,000 molecular weight polyether polyol with propylene oxide added to glycerin, and thoroughly stirring and mixing, defoaming for 20 minutes while stirring under reduced pressure This was used as the polyol component. The hydroxyl value of the polyol component was 19 mgKOH / g. On the other hand, polypropylene glycol-modified polymeric MDI having an NCO content of 11% was used as an isocyanate component and degassed for 20 minutes while stirring under reduced pressure to obtain an isocyanate component.

  The polyol component is mixed with the isocyanate component at a high speed of 3000 rpm with a two-component casting machine so that the ratio of the polyol component to the isocyanate component is 101.75 / 13.70 (isocyanate index: 103). Was poured into a cylindrical mold set with a core metal of φ8 mm, and heated and cured in a hot air circulating oven at 90 ° C. for 60 minutes to prepare a roller body having a base layer made of urethane.

The coating liquid having the composition shown in Table 1 is applied to the outer peripheral surface of the roller body to a predetermined thickness using an ultra die, and then heated and dried at 110 ° C. for 30 minutes to form a coating layer on the outer peripheral surface of the roller. The obtained conductive roller was used as a developing roller.
(Example 2)
SANNICS FA952 [Sanyo Kasei Kogyo Co., Ltd. polyether polyol, OH value = 37] 100 parts by mass, SRX274C [Toray Dow Corning Silicone Co., Ltd. foam stabilizer] 1 part by mass, TOYOCAT NP [Tosoh Corporation Amine Catalyst] 2.8 parts by mass, TOYOCAT EP [amine catalyst manufactured by Tosoh Corporation] 1.5 parts by mass and Sunform IC-716 [Sanyo Kasei Co., Ltd. Tolylene Diisocyanate] 59 parts by mass are mechanically stirred and foamed to obtain a foamed polyurethane raw material. This was poured into a cylindrical mold on which a core metal having an outer diameter of φ8 mm was set. Next, the mold into which the polyurethane foam raw material was injected was heated in an oven at 80 ° C. for 20 minutes, and then removed from the mold to prepare a roller body having a base layer made of urethane foam.

  A conductive roller was produced by forming a coating layer in the same manner as in Example 1 except that the coating liquid having the composition shown in Table 1 was used on the outer peripheral surface of the roller body, and this was used as a developing roller.

(Example 3)
100 parts by weight of Nipol IR2200L (manufactured by Zeon Corporation) with Mooney viscosity ML _{1 + 4} (100 ° C) of 70, 60 parts by weight of LIR-30 (manufactured by Kuraray) with an average molecular weight of 29,000, 28 parts by weight of carbon black TB # 5500 (manufactured by Tokai Carbon) , 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 9 parts by weight of perhexa C-40 (manufactured by NOF Corporation) were kneaded using a 55 L kneader, and a rubber component was prepared. The rubber composition was extruded into a cylindrical shape using a crosshead type extruder from Mitsuba Seisakusho to obtain an unvulcanized rubber / core metal integral molding. This was set in a cylindrical mold, vulcanized at 175 ° C. for 20 minutes under a pressure of 3.2 × 10 ⁶ Pa. The pressure of the split mold was released to obtain a rubber roller, and further vulcanized in an oven at 180 ° C. for 4 hours. The obtained roller was plunge-type polished to a diameter of φ20 mm with a rotating grindstone to produce a roller body having a base layer made of rubber.

  A conductive roller was produced by forming a coating layer in the same manner as in Example 1 except that the coating liquid having the composition shown in Table 1 was used on the outer peripheral surface of the roller body, and this was used as a developing roller.

Example 4
Liquid silicone LIM liquid # 2090 (made by Toray Dow Corning Silicone) is stirred and degassed, then poured into a cylindrical mold set with a core metal with an outer diameter of φ8 mm, and heated in a hot air circulating oven at 120 ° C for 30 minutes Heat cure. The roller with a cored bar was taken out from the cylindrical mold and cured by heating in a hot air circulating oven at 200 ° C. for 4 hours to obtain a roller body provided with a base layer made of silicone rubber.

  A conductive roller was produced by forming a coating layer in the same manner as in Example 1 except that the coating liquid having the composition shown in Table 1 was used on the outer peripheral surface of the roller body, and this was used as a developing roller.

(Example 5)
SANNICS FA952 [Sanyo Chemical Industries, Ltd. polyether polyol, OH value = 37] 100 parts by mass, SRX274C [Toray Dow Corning Silicone Co., Ltd. foam stabilizer] 1 part by mass, TOYOCAT NP [Tosoh Corporation amine catalyst] 2.8 parts by mass, TOYOCAT EP [amine catalyst manufactured by Tosoh Corp.] 1.5 parts by mass and Sunform IC-716 [Sanyo Kasei Co., Ltd. Tolylene Diisocyanate] 59 parts by mass are mechanically stirred to form a foamed polyurethane raw material. Was poured into a cylindrical mold in which a core metal having an outer diameter of φ6 mm was set. Next, the mold into which the polyurethane foam raw material was injected was heated in an oven at 80 ° C. for 20 minutes, and then removed from the mold to prepare a roller body having a base layer made of urethane foam.

The coating liquid having the composition shown in Table 1 is applied to the outer peripheral surface of the roller body with an ultra die and the irradiation intensity is 400 mW and the integrated light quantity is 1000 mJ while rotating the roller using the UNICURE UVH-0252C apparatus manufactured by USHIO INC. / cm ² was irradiated with ultraviolet rays to form an elastic coating layer by instantly curing the coating solution, and a conductive roller having a coating layer on the outer peripheral surface of the roller body was obtained, which was used as a charging roller.

(Example 6)
SANNICS FA952 [Sanyo Chemical Industries, Ltd. polyether polyol, OH value = 37] 100 parts by mass, SRX274C [Toray Dow Corning Silicone Co., Ltd. foam stabilizer] 1 part by mass, TOYOCAT NP [Tosoh Corporation amine catalyst] 2.8 parts by mass, TOYOCAT EP [amine catalyst manufactured by Tosoh Corp.] 1.5 parts by mass and Sunform IC-716 [Sanyo Kasei Co., Ltd. Tolylene Diisocyanate] 59 parts by mass are mechanically stirred to form a foamed polyurethane raw material. Was poured into a cylindrical mold in which a core metal having an outer diameter of φ6 mm was set. Next, the mold into which the polyurethane foam raw material was injected was heated in an oven at 80 ° C. for 20 minutes, and then removed from the mold to prepare a roller body having a base layer made of urethane foam.

  The coating liquid of the composition shown in Table 1 was applied to the outer peripheral surface of the roller body with an ultra die, and while rotating the roller using a Min-EB device manufactured by Ushio Electric Co., Ltd., an acceleration voltage of 30 kV, a tube current of 300 μA, An electron beam was irradiated under conditions of an irradiation distance of 100 mm, a nitrogen atmosphere of 760 Torr, and an irradiation time of 1 minute, the coating liquid was instantly cured to form an elastic coating layer, and a coating layer was provided on the outer peripheral surface of the roller body. A conductive roller was obtained and used as a charging roller.

(Example 7)
After adding 1.6 parts of conductive carbon and 0.15 parts of dibutyltin dilaurate to 100 parts by weight of tri-functional 9,000 molecular weight polyether polyol with propylene oxide added to glycerin, and thoroughly stirring and mixing, defoaming for 20 minutes while stirring under reduced pressure This was used as the polyol component. The hydroxyl value of the polyol component was 19 mgKOH / g. On the other hand, polypropylene glycol-modified polymeric MDI having an NCO content of 11% was used as an isocyanate component and degassed for 20 minutes while stirring under reduced pressure to obtain an isocyanate component. The polyol component is mixed with the isocyanate component at a high speed of 3000 rpm with a two-component casting machine so that the ratio of the polyol component to the isocyanate component is 101.75 / 13.70 (isocyanate index: 103). Was poured into a cylindrical mold in which a core metal of φ6 mm was set, and heated and cured in a hot air circulation oven at 90 ° C. for 60 minutes. A urethane roller with a cored bar was taken out from this mold to obtain a roller body.

  A conductive roller was produced by forming a coating layer in the same manner as in Example 1 except that the coating liquid having the composition shown in Table 1 was used on the outer peripheral surface of the roller body, and this was used as a charging roller.

(Example 8)
After adding 1.6 parts of conductive carbon and 0.15 parts of dibutyltin dilaurate to 100 parts by weight of tri-functional 9,000 molecular weight polyether polyol with propylene oxide added to glycerin, and thoroughly stirring and mixing, defoaming for 20 minutes while stirring under reduced pressure This was used as the polyol component. The hydroxyl value of the polyol component was 19 mgKOH / g. On the other hand, polypropylene glycol-modified polymeric MDI having an NCO content of 11% was used as an isocyanate component and degassed for 20 minutes while stirring under reduced pressure to obtain an isocyanate component. The polyol component is mixed with the isocyanate component at a high speed of 3000 rpm with a two-component casting machine so that the ratio of the polyol component to the isocyanate component is 101.75 / 13.70 (isocyanate index: 103). Was poured into a cylindrical mold in which a core metal of φ8 mm was set, and heated and cured in a hot air circulation oven at 90 ° C. for 60 minutes. The cored urethane roller was taken out from the mold to obtain a roller.

  A conductive roller was produced by forming a coating layer in the same manner as in Example 1 except that the coating liquid having the composition shown in Table 1 was used on the outer peripheral surface of the roller body, and this was used as a developing roller.

(Comparative Example 1)
A conductive roller was produced in the same manner as in Example 1 except that a coating layer was formed by coating a coating liquid having the composition shown in Table 1 on the outer peripheral surface of the roller body by a dip method. A developing roller was used.

(Comparative Example 2)
A conductive roller was prepared by forming a coating layer in the same manner as in Comparative Example 1 except that the coating liquid having the composition shown in Table 1 was used on the outer peripheral surface of the roller body, and this was used as a charging roller.

  As is clear from Table 1, in contrast to Comparative Examples 1 and 2 in which the coating layer was formed by the dipping method, the conductive rollers of the examples were all formed with a uniform coating layer thickness. In an image forming apparatus in which the conductive roller was incorporated as a developing roller or a charging roller, a good image with little unevenness could be obtained.

  The developing roller according to the present invention includes a charging roller, a developing roller, a transfer roller, a paper feeding roller, a toner in an image forming apparatus such as a plain paper copying machine, a plain paper facsimile machine, a laser beam printer, a color laser beam printer, and a toner jet printer. It is preferably used as a supply roller.

It is sectional drawing which shows the electroconductive roller which concerns on this invention. It is a top view which shows the coating device which forms the coating layer of an electroconductive roller. It is sectional drawing which shows the cross section corresponding to the AA arrow of FIG. It is a conceptual diagram which shows the structure of a coating material supply apparatus. It is an external view of the electroconductive roller which shows the state in the middle of applying a coating material to a base | substrate part. It is sectional drawing which shows the surface vicinity of the base | substrate part which consists of foams.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1A Conductive roller 2, 2A Shaft part 3, 3A Base part 4, 4A Coating layer 6 Base part 10 Die coater 11 Ultra die 12 Opening part 13 Guide part 14 Moving base 15 Traverse guide 16 Ball screw 20 Coating device 21 Roller rotation Device 23 Support member 24 Motor 25 Fixed base 29 Piping 31 Paint film band 33 Base part 34 Void cell 34s Void cell exposed on the surface 36, 36A Coating layer 40 Paint supply device 41 Paint pump 42 Filter 43 Motor 44 Storage tank 45 Pressure Total 46 Bypass valve 50 Control device

Claims (7)

A base portion comprising a base layer disposed around the shaft portion and at least one coating layer of a conductive roller having one or more coating layers provided radially outward of the base layer. In the manufacturing method of the conductive roller formed by applying paint to the peripheral surface of
While supplying a paint at a predetermined flow rate to an ultra die having a slit-like opening shorter than the length of the base portion and facing the peripheral surface of the base portion in a direction parallel to the base portion. While rotating the base portion, at least one of the ultra die and the base portion is relatively displaced in the base portion length direction with respect to the other, and the paint supplied to the ultra die is applied from the opening to the peripheral surface of the base portion. A method for producing a conductive roller which is coated to form a coating layer.   2. The conductive roller according to claim 1, wherein a displacement speed when relatively displacing at least one of the ultra die and the base is set so as to be relatively displaced by a distance shorter than the length of the opening while the conductive roller makes one rotation. Manufacturing method.   The conductive roller manufacturing method according to claim 1 or 2, wherein the thickness of the coating layer is controlled by changing at least one of a flow rate of the coating material supplied to the ultra die and a gap between the substrate and the opening. Method.   The method for producing a conductive roller according to any one of claims 1 to 3, wherein the paint has a viscosity of 200 to 10,000 mPa · S at 25 ° C.   The method for producing a conductive roller according to any one of claims 1 to 4, wherein the paint is made of an electron beam curable resin or an ultraviolet curable resin containing an ultraviolet polymerization initiator.   The method for producing a conductive roller according to claim 1, wherein a paint containing particles having an average particle diameter of 1 to 30 μm is supplied to the ultra die.   The shaft portion is pivotally supported at both ends in the length direction, the base layer is disposed around the shaft portion, and one or more coating layers covering the radially outer side of the base layer, and at least one coating layer is claimed in claim The electroconductive roller formed by the manufacturing method of the electroconductive roller in any one of 1-6.

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