JP2007130843A - Demolding method of elastic roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a demolding method of an elastic roller capable of easily ejecting the elastic roller, which is composed of the shaft arranged in the hollow part of a cylindrical mold in parallel to the mold and an elastic layer, which is formed by injecting a material in the hollow part of the cylindrical mold to cure the same, even if the elastic layer is thin. <P>SOLUTION: After the shaft 1 is displaced toward the other side of the mold by a first distance by pushing the end on one side of the mold of the shaft 1, a pressure gas is allowed to flow in the space 23 demarcated by the end surface on one side of the mold of the elastic roller 10 and the inner peripheral surface of the mold and the end on the other side of the mold of the shaft 1 is grasped by a clamp 9 to eject the elastic roller 10 to the other side of the mold. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a demolding method for molding an elastic roller having an elastic layer around a shaft using a mold, and in particular, easily demolding without being affected by the size and material of the elastic layer. About what can be.

  Various elastic rollers such as a charging roller that distributes electric charge to a photosensitive drum are used in copying machines and printers. Such an elastic roller is generally shown in a longitudinal sectional view in FIG. The shaft 1 and the elastic layer 2 disposed around the shaft 1 are configured. In order to manufacture such an elastic roller 10, for example, as shown in a cross-sectional view in FIG. 2, the shaft 1 is disposed in the hollow portion 22 of the cylindrical mold 21, and then a liquid resin is obtained by a mechanical floss method. Alternatively, a liquid foam in which bubbles are dispersed by mixing a rubber material and a gas is prepared, and this liquid foam is injected into the mold hollow portion from one end thereof to fill the mold 21 with the liquid foam. After that, a method of heating and curing this is known (for example, see Patent Document 1).

  Here, a cap 5 for defining both ends of the cavity 11 corresponding to the elastic layer 2 is attached to each end of the shaft 1, and each cap 5 is provided with a hole 5 a leading to the cavity 11. These holes 5a serve as injection ports for injecting material in the cap 5 on one side of the mold for injecting the material, and the cap 5 on the other side of the mold discharges air in the cavity 11 at the time of material injection. Function as an exhaust port.

  Further, as a method of forming the foam-like elastic layer 2 instead of the mecha-floss method, a method using a water foaming method is also known, which forms the elastic layer 2 at a low pressure using water as a foaming agent. is there.

In any method, in order to take out the elastic roller 10 molded in the hollow portion 22 of the mold 21 from the mold 21, the elastic roller 10 is displaced from one side of the mold to the other side. Is performed by pushing one end of the mold of the shaft 1 until the elastic roller 10 is taken out from the other end of the mold (see, for example, Patent Document 1). FIG. FIG. 4 is a cross-sectional view showing a state in which the push rod 6 is pressed against one end of the mold of the shaft 1 and FIG.
JP-A-8-207172

  However, with this conventional method, it is difficult to take out the elastic roller 10 from the mold 21 when the strength of the elastic layer 2 is low, or when the mold inner surface and the elastic layer 2 are poorly releasable. Each has been improving the strength of the material and improving the releasability, but the improvement is still insufficient, and recently the thickness of the elastic layer has been reduced to reduce the material cost. In the case where such an elastic roller is to be molded using the mold 21, the amount of shrinkage in the curing process is reduced by the reduction in thickness, and the mold is reduced. There is a problem that the inner peripheral surface and the outer peripheral surface of the completed elastic layer are pressed against each other with a strong force, and it is difficult to take out the elastic roller simply by pressing the shaft 1 with the push rod 6.

  The present invention has been made in view of such problems, and a shaft disposed in parallel with a mold in a hollow portion of a cylindrical mold, and an elasticity formed by injecting and curing a material into the hollow portion. It is an object of the present invention to provide a method for removing an elastic roller that can easily be removed from a mold even if the elastic roller formed of a layer is an elastic roller having a small elastic layer thickness.

<1> is an elastic roller comprising a shaft disposed in parallel with the mold in a hollow part of a cylindrical mold and an elastic layer formed by injecting a material into the hollow part and curing the mold. In the method of removing the elastic roller that is displaced in the direction and taken out from the mold,
After pressing the end of the mold on one side of the shaft and displacing the shaft by a predetermined distance toward the end on the other side of the mold, one of the mold end surfaces and the inner peripheral surface of the mold are defined. This is a method for removing the elastic roller from which the pressurized gas is introduced into the space, the shaft end located on the opposite side of the pressurized gas is grasped, and the drawer elastic roller is taken out from the mold.

  <2> is a method for flowing the pressurized fluid into the space after displacing the shaft to the other side of the mold by the first distance with the predetermined distance as the first distance in <1>. Prior to this, the elastic roller is removed from the mold by pushing the end of the shaft on the other side of the mold and pushing the shaft back to the mold one side by a second distance.

  <3> is a method for removing the elastic roller in which the predetermined distance is 10 to 20 mm in <1> or <2>.

  <4> is a method for removing the elastic roller in <2> or <3>, in which the second distance is increased by 2 to 10 mm from the first distance.

  <5> is a method for removing the elastic roller in any one of <1> to <4>, wherein the pressure of the pressurized gas flowing into the space is 100 to 400 kPa.

  <6> is a method for removing the elastic roller used in any one of <1> to <5>, wherein the elastic layer is used to form an elastic roller made of a foam body.

  <7> is a method for removing the elastic roller in any one of <1> to <6>, wherein the elastic layer has a thickness of 0.5 to 6 mm.

  According to the invention of <1>, first, the end of one side of the mold of the shaft is pushed, and the shaft is displaced to the other side of the mold by a predetermined distance, thereby bringing the elastic layer and the inner peripheral surface of the mold into close contact with each other. Then, the pressurized gas is caused to flow into a space defined by one end face in the axial direction of the elastic roller and the inner peripheral surface of the mold, so that the mold is interposed between the elastic layer and the inner peripheral surface of the mold. This is a thin elastic layer elastic roller that can form a flow of pressurized gas from one side to the other side and reduce the frictional resistance against the force to take out the elastic roller by using this gas layer as a lubricant layer. However, it can be easily removed from the mold.

  According to <2>, after displacing the shaft to the other side of the mold by a first distance, the end of the shaft on the other side of the mold is made to flow before the pressurized fluid flows into the space. By pushing, the shaft is displaced to one side of the mold by a second distance larger than the first distance, so that the elastic layer residue adhering to the inner peripheral surface of the mold adjacent to one end of the cavity can be peeled off. The mold inner peripheral surface can be kept clean.

  <3> is that the predetermined distance (first distance) is 10 to 20 mm, and when the distance is less than 10 mm, the inner peripheral surface of the mold and the elastic layer are sufficiently separated. Rather, even if the pressurized gas is introduced, it functions as a lubricant, and it becomes difficult to form a gas layer between the inner peripheral surface of the mold and the elastic layer, and demolding is not possible. However, there is a possibility that the inner peripheral surface of the mold and the elastic layer are rubbed with each other without a lubricant and the inner peripheral surface of the mold is damaged.

  <4> is to increase the second distance by 2 to 10 mm from the first distance. If this difference is less than 2 mm, the elastic layer residue cannot be removed, while this difference is less than 10 mm. In the case of exceeding, as described above, the distance for friction between the inner peripheral surface of the mold and the elastic layer without a lubricant becomes longer, and there is a possibility that the inner peripheral surface of the mold is damaged.

  <5> sets the pressure of the pressurized gas flowing into the space to 100 to 400 kPa, and when this pressure is less than 100 kPa, reduces friction between the mold inner peripheral surface and the elastic layer. The gas layer cannot be sufficiently formed and it is difficult to remove the mold. On the other hand, when it exceeds 400 kPa, the pressure of the pressurized gas is too high and the elastic layer may be destroyed.

  According to <6>, since the present invention is applied to the formation of an elastic roller having an elastic layer made of a foam body that is originally low in hardness and difficult to remove from the mold, the effect of easily removing the elastic roller from the mold is further improved. large.

  According to <7>, since it is intended for elastic rollers whose thickness of the elastic layer is originally 6 mm or less, which is difficult to remove from the mold, the effect of facilitating demolding can be further emphasized, When the thickness of the elastic layer is less than 0.5 m, it is difficult to exert the original function of the elastic roller.

  In the case of the elastic roller 10 according to the present invention shown in FIG. 1, the elastic roller 10 includes a shaft 1 and an elastic layer 2 formed around the shaft 1. The elastic roller may be configured by providing one or more surface layers (not shown) having higher hardness than the elastic layer 2. As shown in FIG. 2, the elastic roller 10 has the shaft 1 placed in parallel with the mold 21 in the hollow portion 22 of the cylindrical mold 21, and the foam material is injected into the hollow portion 22 and cured. Formed. In order to form the foam material, a water foaming method can be used in addition to the mechanical floss method.

  The polyurethane material when the elastic layer 2 is formed of polyurethane foam is not particularly limited as long as it contains a urethane bond in the resin. Examples of the polyol component include polyether polyol, polytetramethylene ether glycol, THF-alkylene oxide copolymer polyol, polyester polyol, acrylic polyol, polyolefin polyol, partially saponified product of ethylene-vinyl acetate copolymer, and phosphate system. Polyols, halogen-containing polyols and the like can be suitably used.

  The isocyanate component is not particularly limited, and not only general-purpose TDI, MDI, crude-MDI (polymeric MDI), and modified MDI, but also a special isocyanate may be used. Examples of the special isocyanate include 1,5-naphthalene diisocyanate, tolidine diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, transcyclohexane 1,4 diisocyanate, xylylene diisocyanate (XDI), hydrogenated-XDI, and water. Addition-MDI, lysine diisocyanate, triphenylmethane triisocyanate, tris (isocyanate phenyl) thiophosphate, tetramethylxylene diisocyanate, lysine ester triisocyanate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4- Isocyanatomethyloctane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triiso Aneto, include trimethyl hexamethylene diisocyanate, and they can be used also suitable.

  In the polyurethane material, in addition to these polyurethane raw materials, a crosslinking agent, a foaming agent (water, low-boiling substances, gas bodies, etc.), a surfactant, a catalyst, a foam stabilizer, etc. can be added as desired. Thereby, it can be set as the layer structure as desired.

  In the case of the foaming method, a physical foaming agent generally having a boiling point in the range of 20 to 60 ° C. is preferably used as the foaming agent in consideration of ease of use in the manufacturing process, easiness of vaporization and foaming, and the like. . When such a foaming agent is used as a raw material for the polyurethane foam layer 2, the foaming agent alone has a low viscosity and it is difficult to obtain a stable flow rate in a foaming machine. It is advantageous to use. Specific examples of such foaming agents include n-pentane, isopentane, cyclopentane, methylene chloride, Freon 134a (1,1,1,2-tetrafluoroethane), Freon 245fa (1,1, 1,3,3-pentafluoropropane), Freon 365mfc (1,1,1,3,3-pentafluorobutane), Freon 356, Freon 141b (1,1-dichloro-1-fluoroethane), Freon 142b ( 1-chloro-1,1-difluoroethane) and Freon 22 (chlorodifluoromethane). These may be used alone or in combination of two or more.

  Examples of the catalyst include, for example, organometallic catalysts dibutyltin dilaurate, dibutyltin diacetate, stannous octoate, dibutyltin marker peptide, dibutyltin thiocarboxylate, dibutyltin dimalenate, dioctyltin marker peptide, dioctyltin thiocarboxylate. Rate, phenylmercury, silver propionate, tin octenoate, amine-catalyzed triethylamine, N, N, N ′, N′-tetramethylethylenediamine, triethylenediamine, N-methylmorpholine, dimethylaminoethanol, bis (2-dimethylamino) Ethyl) ether, 1,8-diazabicyclo (5,4,0) -undecene-7 and the like are preferably used. These catalysts may be used alone or in combination of two or more.

  Examples of the foam stabilizer include polyether silicone oil, nonionic surfactant, ionic surfactant and the like, and these may be used alone or in combination of two or more.

  When a surface layer is provided outside the elastic layer 2, the material on which the elastic layer 2 is formed around the shaft 1 is taken out of the mold, and then the surface layer material is applied to the outer surface of the elastic layer. The coating method may be dip coating, spray coating, or roll coater coating.

5 to 8 are sectional views of a mold for explaining a method of taking out the elastic roller 10 from the mold 21, and the length direction of the cavity 11 is respectively provided at both ends of the shaft 1 constituting the elastic roller 10. In order to take out the elastic roller 10 from the mold 21 after the cap 5 for specifying the region is attached and the elastic layer 2 has been cured in the mold 21, as shown in FIG. through the cap 5, press the edge of the mold on one side of the shaft 1 at push rod 6, is displaced by the mold the other side a first distance d ₁ the shaft 1. This step is to release the close contact between the inner peripheral surface of the mold and the elastic layer 2 just formed. The first distance d ₁ when the shaft 1 is displaced is the reason described above. Therefore, the thickness is preferably 10 to 20 mm.

Then, as shown in FIG. 6, through the cap 5, press the edge of the mold other side of the shaft 1 at push rod 7, to displace the shaft 1 to mold one side only second distance d _2. This displacement of the shaft 1 toward one side of the mold is caused by peeling off the elastic layer residue made of polyurethane, for example, from the inner peripheral surface of the mold, which remains at the boundary between the cap 5 and the elastic layer 2 on the inner peripheral surface of the mold. Thus, the elastic layer residue can be easily removed.

As the second distance d ₂ at the time of displacing the shaft 1, preferably larger by 2~10mm than the first distance d ₁ for the reason described above.

  Next, the push rods 6 and 7 are retracted, the end on one side of the mold of the shaft 1 is gripped by the clamp 9, and the air supply adapter 8 is disposed on the other end of the mold 21. The air supply adapter 8 seals the end surface of the mold 21 with the seal portion 8b, so that the inner peripheral surface of the mold 21 and the end surface on one side of the mold of the elastic roller 10 (or the cap 5 as shown in FIG. In some cases, a closed space 23 surrounded by the cap 5) and the air supply adapter 8 is defined. The air supply adapter 8 is provided with a hole 8 a for sending pressurized air to the closed space 23, and the closed space 23 is pressurized by flowing pressure gas into the air supply adapter 8. Has been.

  In addition, as long as the air supply adapter 8 and the clamp 9 are arranged at the ends opposite to each other in the mold length direction, any one of them may be arranged on one side.

  When pressurized air is supplied to the closed space 23, the pressurized air acts to push the elastic roller 10 toward the other side of the mold, and at the same time, creates a gap between the elastic layer 2 and the inner peripheral surface of the mold. A flow that passes through and flows out to the other side of the mold is generated, and this flow functions as a lubricant when the elastic layer 2 and the inner peripheral surface of the mold are relatively displaced.

  At this time, the clamp 9 holds the other end of the mold of the shaft 1 and pulls out the elastic roller 10 to the other side of the mold to take out the elastic roller 10 from the mold 21. The pulling force when pulling out is firstly that a gas fluidized layer exists between the elastic layer 2 and the inner peripheral surface of the mold and the frictional force there is very small, and secondly, the applied force of the closed space 23 is increased. Since the pushing force for displacing the elastic roller 10 to the other side of the mold acts by the pressure of the compressed air, it is possible to use an extremely small force, and the elastic roller 10 can be easily taken out from the mold 21.

  Actually, the method of taking out the elastic roller 10 from the mold 21 by simply pushing one end of the mold of the shaft 1 with the push rod 6 for the two types of rollers A and B is described above as a conventional example. As described above, the push rollers 6 and 7 are used to reciprocate the elastic roller 10 left and right by the first and second distances, respectively, and then the air supply adapter 8 is used to move the elastic roller 10 to the one end of the die. Using the method according to the present invention, in which pressurized air is supplied and the elastic roller 10 is taken out from the mold 21, the molded elastic roller 10 is operated to be taken out from the mold by the method according to each example. , Investigated the success or failure of removal. The number of pick-up operations was 50 for each roller and each example. The result of the success / failure of taking out is shown in Table 1.

The specifications of roller A and roller B are as shown in Table 2. In the example, the first distance d ₁ displaced by the push rod was 15 mm, the second distance d ₂ was 20 mm, and the pressure of the air supplied from the air supply adapter 8 was 400 kp.

The material M1 and the material M2 in Table 2 were formed according to the following.
<Material M1>
100 parts by mass of urethane prepolymer synthesized from tolylene diisocyanate (TDI) and polyether polyol and 2 parts by mass of acetylene black are mixed to prepare a urethane prepolymer in which acetylene black is dispersed. On the other hand, 30 parts by weight of polyether polyol and 0.1 part by weight of sodium perchlorate (NaClO ₄ ) were mixed while heating to 70 ° C., and 4.5 parts by weight of polyether-modified silicone oil (foam stabilizer) and dibutyltin Dilaurate (catalyst) 0.2 parts by mass was mixed to prepare a mixture, which was used as B component, and these A component and B component were foamed by a mechanical floss method.
<Material M2>
As the polyether polyol, propylene oxide / ethylene having 3 functional groups, a weight average molecular weight of about 5,000, a proportion of ethylene oxide of about 13% by mass, and a proportion of terminal hydroxyl groups of primary hydroxyl groups of about 80%. Oxide addition-polymerized polyether polyol (FA703, Sankyo Kasei Co., Ltd.) was used, and tolylene diisocyanate (TDI-80) and crude diphenylmethane diisocyanate (crude MDI) were used as isocyanate, and 100 parts by mass of FA703. , 80 parts by mass of TDI-80 and 20 parts by mass of crude MDI were mixed and stirred (water foaming method). Diethanolamine was also mixed as a crosslinking agent.

  The present invention can be used for various elastic rollers formed by a mechanical floss method or a water foaming method. As the elastic roller, a charging roller for charging the photosensitive drum, or a non-conductive roller formed according to a latent image formed on the photosensitive drum. Examples thereof include a developing roller that transfers the magnetic toner, a toner supply roller that supplies the toner to the developing roller, and a transfer roller that transfers the toner on the photosensitive drum to the printing paper.

It is sectional drawing which shows the elastic roller which concerns on this invention. It is sectional drawing of the metal mold | die for demonstrating the molding method of an elastic roller. It is sectional drawing of the metal mold | die for demonstrating the conventional mold release method. It is sectional drawing of the metal mold | die which shows the process following FIG. It is sectional drawing of the metal mold | die for demonstrating the demolding method of embodiment of this invention. It is sectional drawing of the metal mold | die which shows the process following FIG. It is sectional drawing of the metal mold | die which shows the process following FIG. It is sectional drawing of the metal mold | die which shows the process following FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft 2 Elastic layer 5 Cap 5a Cap hole 6, 7 Push rod 8 Air supply adapter 8a Air supply adapter hole 8a Seal part of air supply adapter 9 Clamp 10 Elastic roller 11 Cavity 21 Mold 22 Mold hollow part 23 Closed space

Claims (7)

An elastic roller composed of a shaft disposed in parallel with the mold in the hollow part of the cylindrical mold and an elastic layer formed by injecting and curing a material into the hollow part is displaced in the mold length direction. In the method for removing the elastic roller from the mold,
After pressing the end of the mold on one side of the shaft and displacing the shaft by a predetermined distance toward the end on the other side of the mold, one of the mold end surfaces and the inner peripheral surface of the mold are defined. The elastic roller is removed from the mold by allowing the pressurized gas to flow into the space, gripping the shaft end located on the opposite side of the pressurized gas and pulling out the elastic roller from the mold.   The predetermined distance is the first distance, and the shaft is displaced by the first distance to the other side of the mold, and then the pressurized fluid is allowed to flow into the space before the other side of the mold of the shaft. The elastic roller demolding method according to claim 1, wherein the shaft is pushed back by a second distance to one side of the mold.   The elastic roller demolding method according to claim 1 or 2, wherein the predetermined distance is 10 to 20 mm.   4. The elastic roller demolding method according to claim 2 or 3, wherein the second distance is made larger by 2 to 10 mm than the first distance.   The method for removing the elastic roller according to any one of claims 1 to 4, wherein the pressure of the pressurized gas flowing into the space is set to 100 to 400 kPa.   6. The elastic roller demolding method according to claim 1, wherein the elastic layer is an elastic roller formed of a foam body.   The elastic roller demolding method according to claim 1, wherein the elastic layer has a thickness of 0.5 to 6 mm.

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