JP4679330B2 - OA blade forming method and blade forming mold - Google Patents

Description

  The present invention relates to a method of forming an OA blade comprising a strip-shaped metal plate and an elastic member integrally disposed in parallel with the metal plate on at least one surface of the metal plate, and particularly, elastic in a short time. It is related with what can harden a member.

  In electrophotographic or electrostatic recording type image forming apparatuses such as copying machines, facsimiles, printers, etc., particularly for color, there is a method in which a non-magnetic developer is charged and the developer is transferred to the photosensitive drum by the charge. In this system, the developer is carried on the outer periphery of the developing roller, and the amount of developer supplied by the rotating developing roller is attached in a posture facing the outer peripheral surface, and the developer amount is regulated. The blade is regulated by the blade and the developer is triboelectrically charged by the blade.

  As the developer amount regulating blade, an elastic member such as silicone rubber having a sufficient flexibility to form a gap through which the developer passes and characteristics necessary for frictionally charging the developer is formed into a thin strip shape. Often used are those bonded to a metal plate.

  Further, in the above image forming apparatus, a cleaning blade for cleaning the surface of the photosensitive drum is one in which an elastic member such as silicone rubber is bonded to one side of a thin strip-shaped metal plate. The developer attached to the photosensitive drum is scraped off by being pressed against the rotating photosensitive drum.

  A blade (hereinafter referred to as “OA blade” in the present specification) having a structure in which an elastic member is bonded to the metal plate, such as a developer amount regulating blade and a cleaning blade, which is attached to an OA apparatus is conventionally known. Then, insert the metal plate coated with adhesive into the mold, fill the mold cavity with the rubber material using the transfer molding method or injection molding method, and metal the elastic member molded in the mold There is known a method of forming a film by adhering it to a plate (for example, see Patent Document 1).

  FIG. 1 is a diagram showing a developer amount regulating blade as an example of such an OA blade. FIG. 1 (a) is a schematic view showing an attachment mode of the blade, and FIG. 1 (b) is a plan view thereof. FIG. 1C is a perspective view, and the developer amount regulating blade 90 is disposed in a posture in contact with the circumferential surface 93a of the rotating developing roller 93 or in a posture having a slight gap with the circumferential surface 93a. An elastic member 92 made of, for example, silicone rubber, which functions to regulate the layer thickness of the developer 94 on the peripheral surface 93a of the developing roller and is in direct contact with the developer, is provided on one surface 91a of the belt-shaped metal plate 91. It is formed by adhering to.

  When the viscosity of the material for forming the elastic member is high, the cavity is long and the flow path in the cavity is long, so that shape defects such as insufficient filling and sink marks tend to occur at the end of the flow path. In order to prevent this problem, burrs are likely to occur when the material is injected at a high pressure, and when a plurality of gates are provided to shorten the flow path, the flow from these gates is reduced. A defect that a weld line formed by collision occurs.

As a countermeasure, it has been proposed to form an OA blade by a LIM molding method using a liquid composition having a low viscosity as a material (see, for example, Patent Document 1).
JP 2005-274646 A

  However, in the conventional LIM molding using liquid silicone rubber or the like, since heat is applied to cure, there is a problem in that it takes a long time to cure. Even when a liquid material is not used, shortening the curing time has been an important issue for improving productivity, if not as much as the liquid material.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a method for forming an OA blade capable of improving the productivity by shortening the curing time, and a mold therefor. And

<1> is a method of forming an OA blade including a band-shaped metal plate and an elastic member integrally disposed in parallel with the metal plate on at least one surface of the metal plate.
The mold cavity into which the metal plate is inserted is filled with an ultraviolet curable composition as a material of the elastic member, and the cavity is filled with the composition, and then the entire area in the cavity is irradiated with ultraviolet rays. It is the formation method of the OA blade which hardens the said composition.

  <2> In <1>, a mold in which a transparent body adjacent to the outside is disposed in a part defining the cavity is used as the mold, and ultraviolet rays are allowed to pass through the transparent body and enter the cavity. This is a method of forming an OA blade to be irradiated.

  <3> is a method for forming an OA blade using a rubber composition as the ultraviolet curable composition in <1> or <2>.

  <4> is a method for forming an OA blade using the resin composition as the ultraviolet curable composition in <1> or <2>.

<5> is a blade forming mold used in the method for forming an OA blade according to any one of <1> to <4>,
It consists of a fixed mold and a movable mold that form a cavity close to each other. At least one of these molds includes a transparent body that allows incident ultraviolet rays to pass through the cavity, and a distribution and direction of ultraviolet rays that enter the transparent body. A gate forming die that is configured by a valve gate that can be opened and closed.

  <6> is for blade molding according to <5>, wherein the lens is configured to emit ultraviolet rays in a direction perpendicular to the cavity length direction and with a uniform distribution in the cavity length direction. It is a mold.

  <7> is the blade forming mold according to <6>, wherein the illuminance of ultraviolet light incident on the transparent body is within ± 30% of the average value in the length direction.

  <8> is a blade forming die in which a tab is provided in a portion of the cavity adjacent to the valve gate in any one of <5> to <7>.

  <9> is a blade forming mold in which the cavity defining surface of the transparent body is a flat surface in any one of <5> to <8>.

  According to <1>, the mold cavity into which the metal plate is inserted is filled with the ultraviolet curable composition that is the material of the elastic member, and the cavity is filled with the composition, and then the entire area in the cavity is filled. Since the composition is cured by irradiating with UV rays, it can be molded in a short time compared to the case where the composition is heated and cured using a thermosetting composition, thereby improving productivity. be able to. Furthermore, since the mold used in this forming method does not need to be heated, complicated devices such as a temperature control facility and a mold with a temperature control jacket, which are necessary for a thermosetting composition, are not required. At the same time, it is possible to eliminate the energy loss caused by the constant temperature control and to make it economically advantageous.

  According to <2>, as a mold, a part defining a cavity is used and a transparent body adjacent to the outside is disposed, and ultraviolet rays are passed through the transparent body and irradiated into the cavity. Ultraviolet rays can be easily incident on the entire area of the cavity.

  According to <3>, since the rubber composition is used as the ultraviolet curable composition, it is possible to form a molded article having flexibility and desired elasticity.

  According to <4>, since the resin composition is used as the ultraviolet curable composition, it is possible to form a molded article having excellent dimensional accuracy and desired hardness.

  According to <5>, the transparent body that allows the incident ultraviolet light to pass through the cavity and the lens that determines the distribution and direction of the ultraviolet light that is incident on the transparent body are provided. Then, the ultraviolet curable composition can be cured, and the thermosetting composition can be molded in a short time compared with the case where the composition is heated and cured, and the productivity can be improved. . In addition, since the gate is configured by a valve gate that can be opened and closed by an external signal or the like, it is possible to prevent leakage of uncured material in the cold runner by closing the gate when the mold is opened. .

  According to <6>, since the lens is configured to emit ultraviolet rays in a direction perpendicular to the cavity length direction and with a uniform distribution in the cavity length direction, the ultraviolet rays filled in the cavity The curable composition can be uniformly cured over the entire length, and as a result, a blade having uniform characteristics in the length direction can be formed.

  <7> is intended to make the illuminance of ultraviolet light incident on the transparent body within ± 30% of the average value in the length direction, and the illuminance exceeded 130% or less than 70% of the average value. In this case, the variation in illuminance depending on the position in the length direction is large, so the variation in the degree of curing increases, and as a result, the variation in the length direction of the hardness and shrinkage rate increases, and stable characteristics can be obtained over the long term Will become difficult.

  According to <8>, since the tab is provided in the cavity adjacent to the valve gate, the rapid flow change of the material injected from the gate can be accommodated in the tab forming portion that forms the tab. It is possible to suppress the influence on the elastic member main body and form a highly accurate blade.

  According to <9>, since the cavity defining surface of the transparent body is configured as a flat surface, the transparent body can be made inexpensive, which is preferable.

  The OA blade according to the forming method of the present invention is as illustrated in FIG. 1 as a conventional developer regulating blade, and FIG. 2 is a sectional view showing a mold for forming the OA blade 90, FIG. FIG. 4A is a perspective view showing a fixed mold, and FIG. 4B is a perspective view of a “b” portion of FIG. 4A. It is a perspective view showing details.

  The mold 10 for forming the OA blade 90 includes a fixed mold 13 and a movable mold 12 that is displaced up and down with respect to the fixed mold 13. When the mold 10 is closed, the movable mold 12 and the fixed mold 10 are formed. 13 abuts to define a cavity 16.

  The fixed mold 12 is configured by mounting a insert piece 21 and a transparent body 17 that passes ultraviolet light incident from the outside and guides it to the cavity 16 on a fixed mold main body 33, and the transparent body 17 is formed by a transparent body holding plate 19. It is fixed to the fixed mold body 33. The fixed mold 12 is provided with a cold runner 14 that serves as a passage to the cavity 16 of the ultraviolet curable composition that is a molding material, and the molding material is applied to the gate portion that serves as an opening to the cavity 16 of the cold runner 14. A valve gate 15 having an opening / closing function that can be passed or blocked is arranged.

  In order to open and close the valve gate 15, an open / close pin 23 that moves up and down in the cold runner 14 is provided, and the open / close pin 23 is located at the lowest point in the process of injecting the material, and opens the valve gate 15. In this process, the valve gate 15 is operated to close at the uppermost point. For this opening and closing, a cylinder 25 for moving the piston 24 connected to the opening and closing pin 23 up and down is provided.

  The fixed mold 12 is provided with a UV lens 18 for making ultraviolet rays incident on the transparent body 17, and the UV lens 18 is connected to an ultraviolet irradiation device 29 through an optical fiber 27. The material of the transparent body 17 may be a transparent material that has sufficient strength to withstand the injection pressure as a mold material and can transmit ultraviolet rays. For example, quartz glass, borosilicate glass Transparent glass such as, transparent plastic, etc. can be used. Moreover, it is preferable that the cavity surface 17s of the transparent body 17 is a flat surface, and the transparent body 17 can be made relatively inexpensive and highly accurate.

  Here, as the UV lens 18, for example, a UV fiber lens capable of bundling a large number of optical fibers that pass ultraviolet rays and diffusing, converging, or collimating them in a desired direction can be used. In order to make the main body 92a of the elastic member 92 uniform in the length direction, the ultraviolet curable composition in the cavity 16 is uniformly irradiated by irradiating ultraviolet rays uniformly and perpendicularly in the cavity length direction. It is necessary to cure, and the irradiation distribution in the cavity length direction is preferably within ± 30% of the average value.

  The cavity 16 includes a body cavity portion 30 corresponding to the body portion 92 a of the elastic member 92, a tab forming portion 31 corresponding to the tab 92 b of the elastic member 92, and an insert space 32 for placing the metal plate 91. Is done.

  In the above-described embodiment, the movable mold 12 is illustrated as a mold on the side to be displaced, and the fixed mold 13 is illustrated as a mold on the side that is not displaced. However, the mold 12 is disposed on the side on which the mold 13 is displaced. In addition, any of these molds 12 and 13 can be configured to be displaced.

  The blade 90 is formed using the mold 10 as described above as follows. As shown in FIG. 1, with the nozzle 22 of the injection molding machine pressed against the inlet of the cold runner 14, the fixed mold 12 and the movable mold 13 are brought close to each other to close the mold 10 and the cavity 16. After the formation, the valve gate 15 is opened, and the ultraviolet curable composition as the material of the molded product is supplied from the injection molding machine through the cold runner 14 into the cavity 16, and the interior of the cavity 16 is irradiated with the ultraviolet curable composition. Fill with things.

  Next, ultraviolet rays are irradiated from the UV lens 18 into the cavity 16 through the transparent body 17. At this time, since the material filled in the cavity 16 is a composition that is cured by ultraviolet rays, the composition of the cavity 16 is cured by this operation, and if the amount of ultraviolet rays is sufficient, it is cured in a very short time. .

  After a preset time necessary for completely curing the ultraviolet curable composition in the cavity 16, the fixed mold 12 and the movable mold 13 are separated from each other to open the mold, and the molded product is cured. Is removed from the cavity 16 to complete the series of cycles.

  In addition, it is necessary to close the valve gate 15 before the mold 10 is opened after the ultraviolet curable composition is filled in the cavity 16, and if this is not closed, Since the material held in the cold runner 14 is not cured by being irradiated with ultraviolet rays, there arises a problem that leakage starts as soon as the mold is opened. For the same reason, it is not possible to use a pin gate without an opening / closing function used for molding a thermosetting composition in place of the valve gate 15.

  Examples of the ultraviolet curable composition used in this manner include the following.

  Examples of the ultraviolet curable composition used in this manner include the following. Examples of the resin composition include polyester resin, polyether resin, fluororesin, epoxy resin, amino resin, polyamide resin, acrylic resin, acrylic urethane resin, urethane resin, alkyd resin, phenol resin, melamine resin, urea resin, silicone resin, Polyvinyl butyral resin, vinyl ether-based resin, vinyl ester-based resin, etc., and as rubber compositions, terminal acrylated 1,4-polybutadiene rubber, terminal acrylated 1,2-polybutadiene rubber, terminal acrylated hydrogenated 1,2 -Polybutadiene rubber, terminal acrylated polyisoprene rubber, terminal acrylated hydrogenated polyisoprene rubber and the like can be mentioned, and one or more of these can be used in combination.

  Furthermore, a modified resin in which a specific functional group is introduced into the resin can also be used. In order to improve the mechanical strength and environmental resistance, it is preferable to introduce those having a crosslinked structure.

  Among the above compositions, a composition formed from a (meth) acrylate-based one containing a (meth) acrylate oligomer is particularly preferable.

  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:

  The composition is blended with a reactive diluent having a polymerizable double bond for viscosity adjustment as necessary. 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.

  When using a composition that is cured by ultraviolet irradiation as an ultraviolet liquid curable composition, an ultraviolet polymerization initiator for accelerating the initiation of the curing reaction of the resin in the formation process is contained in the composition.

  As such an ultraviolet polymerization initiator, known ones can be used, for example, 4-dimethylaminobenzoic acid, 4-dimethylaminobenzoic acid ester, 2,2-dimethoxy-2-phenylacetophenone, acetophenone diethyl Benzophenone derivatives such as ketals, alkoxyacetophenones, benzyldimethylketals, benzophenones and 3,3-dimethyl-4-methoxybenzophenones, 4,4-dimethoxybenzophenones, 4,4-diaminobenzophenones, alkyl benzoylbenzoates, bis (4-dialkyls) Aminophenyl) ketone, benzyl derivatives such as benzyl and benzylmethyl ketal, benzoin derivatives such as benzoin and benzoin isobutyl ether, benzoin isopropyl ether, 2-hydroxy 2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, xanthone, thioxanthone and thioxanthone derivatives, fluorene, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4 4-trimethylpentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl 2-dimethylamino-1- (morpholinophenyl) -butanone-1 and the like. These may be used individually by 1 type and may use 2 or more types together.

  When mix | blending a ultraviolet-ray polymerization initiator, the compounding quantity is 0.1-10 weight part per 100 weight part of (meth) acrylate oligomers, for example.

  In the present invention, in addition to the above components, if necessary, tertiary amines such as triethylamine and triethanolamine, and alkylphosphine photopolymerization such as triphenylphosphine in order to promote the polymerization reaction by the above polymerization initiator. An accelerator, a thioether photopolymerization accelerator such as p-thiodiglycol, and the like may be added to the composition that is cured by ultraviolet rays. When these compositions are added, the addition amount is usually preferably in the range of 0.01 to 10 parts by weight per 100 parts by weight of the (meth) acrylate oligomer.

  The blade forming method and the mold for the same according to the present invention can also be applied to form various molded products.

FIG. 4 is an attachment mode diagram, a plan view, and a perspective view showing a developer amount regulating blade. It is sectional drawing which shows the metal mold | die for forming OA blade. It is sectional drawing corresponding to the AA arrow of FIG. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mold 12 Movable type 13 Fixed type 14 Cold runner 15 Valve gate 16 Cavity 17 Transparent body 18 UV lens 19 Transparent body pressing plate 21 Inserting piece 23 Opening / closing pin 24 Piston 25 Cylinder 29 Ultraviolet irradiation device 30 Main body cavity part 31 Tab formation part 32 Insert space 33 Fixed mold main body 90 Developer amount regulating blade 91 Metal plate 91a One side surface of metal plate 92a Elastic member main body 92b Elastic member tab 93 Developing roller 94 Developer

Claims (9)

In a method of forming an OA blade comprising a band-shaped metal plate and an elastic member integrally disposed in parallel with the metal plate on at least one surface of the metal plate,
The mold cavity into which the metal plate is inserted is filled with an ultraviolet curable composition as a material of the elastic member, and the cavity is filled with the composition, and then the entire area in the cavity is irradiated with ultraviolet rays. A method for forming an OA blade for curing the composition.   2. The OA blade according to claim 1, wherein as the mold, a part defining a cavity is provided with a transparent body adjacent to the outside, and ultraviolet rays are irradiated into the cavity through the transparent body. Forming method.   The method for forming an OA blade according to claim 1, wherein a rubber composition is used as the ultraviolet curable composition.   The method for forming an OA blade according to claim 1, wherein a resin composition is used as the ultraviolet curable composition. A blade forming mold used in the method for forming an OA blade according to any one of claims 1 to 4,
It consists of a fixed mold and a movable mold that form a cavity close to each other. At least one of these molds includes a transparent body that allows incident ultraviolet rays to pass through the cavity, and a distribution and direction of ultraviolet rays that enter the transparent body. A blade forming mold comprising a valve gate that can be opened and closed, and a gate portion that serves as an entrance to the cavity of the composition.   The blade molding die according to claim 5, wherein the lens is configured to emit ultraviolet rays in a direction perpendicular to the cavity length direction and with a uniform distribution in the cavity length direction. The blade forming mold according to claim 6, wherein the illuminance of ultraviolet rays incident on the transparent body is within ± 30% of the average value in the length direction.   The blade forming mold according to any one of claims 5 to 7, wherein a tab is provided in a portion of the cavity adjacent to the valve gate.   The blade forming mold according to any one of claims 5 to 8, wherein the cavity defining surface of the transparent body is formed of a flat surface.

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