JP2010137417A - Method of manufacturing polyurethane sponge roller, and toner feed roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a polyurethane sponge roller capable of removing the polyurethane sponge roller from a pipe mold without a split and a crack on the surface of the polyurethane sponge roller, and to provide a toner feed roller. <P>SOLUTION: The method of manufacturing a polyurethane sponge roller cured around a core bar preliminarily arranged in a mold comprises: foaming and curing a polyurethane material in the mold; then holding and fixing the core bar; giving the mold the force perpendicular to the shaft of the core bar from four directions or more approximately equally dividing a circle having a center at the shaft; removing the outer surface of the polyurethane sponge roller from the inner surface of the mold; and then removing the polyurethane sponge roller from the mold wherein the deformation of the mold by the force given to the mold is not less than 20% to not more than 70% of the thickness of the polyurethane sponge layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a polyurethane sponge roller and a toner supply roller used in an image forming apparatus such as a copying apparatus, an image recording apparatus, a printer, and a facsimile machine.

  The toner supply roller, transfer roller, developing roller, charging roller, etc. used in dry electrophotographic apparatus are polymer elastomers such as polyurethane, NBR (acrylonitrile butadiene rubber), EPDM (ethylene propylene diene rubber), and silicone rubber in the elastic layer. And sponges have been used. In particular, when the elastic body needs to have a lower hardness, a polyurethane sponge is often used. For example, the toner supply roller needs to have a low hardness, and a polyurethane sponge is often used (Patent Document 1). That is, highly foamed polyurethane by a method using a foaming agent such as water or a low boiling point compound, a method by a foaming process by mechanical stirring without a foaming agent, or a method in which these foaming agents are combined with a foaming process by mechanical stirring. A sponge is easily obtained. As described above, an elastic body having a low hardness can be easily obtained by using the polyurethane sponge, and the hardness of the roller can be controlled by selecting raw materials and blends that determine the chemical structure of the polyurethane.

  When manufacturing such a polyurethane sponge roller, generally, a core metal is set in a pipe mold, polyurethane material is injected into the mold, foamed and cured, and then the polyurethane sponge is discharged from the pipe mold. It is manufactured through a process of removing the roller.

  Conventionally, as a method for removing a roller, the roller is extracted from the pipe die by pushing one end of the core bar to the other end side. However, in this method, the releasability between the polyurethane sponge layer and the pipe mold wall surface is poor. In other words, if the polyurethane sponge layer and the pipe mold wall surface are bonded, it is excessive when one end of the core metal is pushed to the other end side. Since a heavy load is applied to the polyurethane sponge layer, the polyurethane sponge layer surface may sometimes tear or crack. In particular, when the length of the urethane foam layer in the longitudinal direction such as for A3 is long, there is a problem that the load at the time of demolding tends to be larger, and the surface of the polyurethane foam layer is easily torn and cracked.

  In order to solve these problems, a method has been proposed in which a core metal is pushed while a compressed gas such as air is introduced from the push-side end portion when one end of the core metal is pushed to the other end side (Patent Document 1). However, in the method of Patent Document 1, depending on the releasability between the polyurethane sponge layer and the pipe mold wall surface, the polyurethane sponge layer surface may not peel from the pipe mold wall surface even if compressed gas is introduced. Improvements have been sought before cracking and cracking of the layer surface has been resolved.

  Also, in order to remove the mold more securely, the core metal is displaced in the radial direction of the pipe mold to form a gap between the polyurethane sponge layer and the pipe mold wall surface, and then one end of the core metal is pushed and removed. A method to do this has been proposed (Patent Document 2). However, as disclosed in Patent Document 2, when at least one end of the core metal is displaced only from one direction in the radial direction of the pipe mold, the polyurethane sponge can be used even if the core metal is displaced in the radial direction of the pipe mold. The gap formed between the layer and the pipe mold wall is a part of the roller surface and does not form a gap over the entire circumference of the roller. Cracking sometimes occurred. Further, when at least one end of the core metal is displaced only in one direction in the radial direction of the pipe mold, if the displacement amount is increased to increase the displacement of the polyurethane sponge layer so as to form a gap over the entire circumference of the roller or a wider range. There was a case where a large load was applied to a part and it was torn.

Furthermore, when gripping the cored bar and displacing the cored bar, it is easier to form a gap between the polyurethane sponge layer and the pipe mold wall surface by moving the chuck in synchronization with the gripping of both ends of the cored bar. In some cases, it is complicated by the entanglement of the movement accuracy at both ends.
JP 2007-130443 A JP 2007-276252 A

  The present invention has been made in view of such circumstances of the prior art. The problem to be solved is a polyurethane composed of a core metal disposed on the central axis of a pipe mold and a polyurethane sponge layer formed by injecting a polyurethane sponge layer material into the hollow portion of the pipe mold and curing it. It is an object of the present invention to provide a polyurethane sponge roller manufacturing method and a toner supply roller in which the sponge roller is removed from the pipe mold without causing the surface of the polyurethane sponge layer to tear or break.

  The present invention, which has solved the above-mentioned problems, is a method for producing a polyurethane sponge roller that is cured around a cored bar that has been placed in advance in a mold, and after foaming and curing a polyurethane material in the mold, Holding and fixing, a force substantially perpendicular to the axis of the core metal is applied to the die from four or more angular directions of the circumference of the axis obtained by dividing a circle centered on the axis substantially evenly, The polyurethane sponge roller is manufactured through a step of peeling the surface of the polyurethane sponge roller from the inner surface of the mold and then a step of removing the polyurethane sponge roller. In the step of peeling, the polyurethane sponge roller is added to the die. The polyurethane roller manufacturing method is characterized in that the amount of displacement of the mold due to the applied force is 20% to 70% of the thickness of the polyurethane sponge layer.

  The present invention also provides a toner supply roller comprising a polyurethane sponge roller manufactured by the above-described method of manufacturing a polyurethane sponge roller, wherein the toner supply roller abuts against the surface of the developing roller at a developing mechanism portion of an electrophotographic apparatus or electrostatic recording apparatus. And a toner supply roller that supplies toner to the surface of the developing roller.

  According to the present invention, a polyurethane sponge roller comprising a core metal disposed on the center axis of a pipe mold and a polyurethane sponge layer formed by injecting a polyurethane sponge layer material into a hollow portion of the pipe mold and curing the polyurethane sponge roller is made of polyurethane. It is possible to provide a method for producing a polyurethane sponge roller and a toner supply roller that can be removed from a pipe mold without causing the surface of the sponge layer to tear or break.

  The present invention relates to a method for producing a polyurethane sponge roller which is cured around a core metal previously disposed in a mold, and after foaming and curing a polyurethane material in the mold, the core metal is gripped and fixed, A force substantially perpendicular to the axis of the core metal is applied to the mold from four or more angular directions of the circumference of the axis obtained by dividing a circle centered on the axis substantially evenly. The displacement amount of the polyurethane sponge layer is 20% or more and 70% or less of the thickness of the polyurethane sponge layer, and after the step of peeling the surface of the polyurethane sponge roller from the inner surface of the mold while pressing the polyurethane sponge, A process for producing a polyurethane sponge roller, wherein the polyurethane sponge roller is produced through a step of demolding.

  The present invention is described in more detail below. First, the method for producing a polyurethane sponge roller of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

  The polyurethane sponge roller demolding method of the present invention is formed by injecting polyurethane material into the core metal 1 disposed on the central axis of the pipe mold 3 shown in FIG. In this method, the polyurethane sponge roller composed of the polyurethane sponge layer 2 is removed.

  First, as shown in FIG. 3, the center axis of the pipe mold 3 is displaced in a direction perpendicular to the center axis in the longitudinal direction of the core metal 1 so as to shift the coaxial axis. By displacing, force is applied to the polyurethane sponge layer 2 and a part of the polyurethane sponge layer is peeled off from the wall surface of the pipe mold. Next, as shown in FIG. 4, a force perpendicular to the core metal axis is applied to the pipe mold from four or more angular directions obtained by dividing the circle whose center is centered on the core metal axis substantially evenly.

  In this way, by applying a force perpendicular to the core metal axis to the pipe mold from four or more angular directions in which the angular direction divides a circle centered on the core metal axis approximately evenly, the polyurethane sponge layer 2 And the peeling part of the wall surface of the pipe mold spreads all over the polyurethane sponge layer. Thereafter, the displacement is returned, and the polyurethane sponge roller is removed from the pipe mold 3 by pushing one end of the core metal 1 in the direction of the central axis of the core metal as shown in FIG. In FIG. 5, the core 4 is pulled out from the pipe mold 3 using the shaft 4, but the present invention is not limited to this. For example, compressed air is introduced into the pipe mold from the end of the pipe mold. The polyurethane sponge layer may be pressurized by supplying and the polyurethane sponge roller may be pulled out or extruded. By completely peeling the polyurethane sponge layer 2 and the pipe mold wall once and then removing the mold, the load on the polyurethane sponge layer surface when removing the polyurethane sponge roller can be greatly reduced.

  When a force perpendicular to the core metal axis is not applied to the pipe mold from four or more angular directions obtained by dividing the circle around the core axis substantially evenly, the polyurethane sponge layer 2 and the pipe mold The wall surface may not be completely peeled off. Therefore, when the polyurethane sponge roller is removed from the state where it is not completely peeled off, a large load is applied to the surface of the polyurethane sponge layer that is not completely peeled off, and the surface of the polyurethane sponge layer may be torn. When a force perpendicular to the cored bar axis is applied to the pipe mold from three angular directions, a circle centered on the cored bar axis is approximately evenly divided and applied to about 120 degrees. Although the peeling part of the polyurethane sponge layer 2 and the wall surface of the pipe mold spreads over the entire area of the polyurethane sponge layer, depending on the hardness and density of the polyurethane sponge layer, the entire area of the polyurethane sponge layer may not be peeled off, resulting in poor reliability. If there are too many angular directions of the force perpendicular to the core axis in the pipe mold, the apparatus for displacing the mold becomes complicated, resulting in poor productivity and cost. Also, if the angle direction of the force perpendicular to the core metal axis is too uneven in the pipe mold, too much load will be applied to the foam, and excessive compression force will be exerted on the polyurethane sponge layer on the opposite side of the peeling area. In some cases, the polyurethane sponge layer itself may be destroyed, so that the force perpendicular to the core metal axis is applied to the pipe mold from four to eight directions, and the angular direction is centered on the core metal axis. The circle to be added is preferably added from an angular direction divided substantially equally, and more preferably about 90 degrees or less. When the angle direction is preferably 8 directions or less, the angle direction is about 45 degrees or more.

  A larger displacement x between the central axis of the core metal 1 and the central axis of the pipe mold 3 is preferable because the peeling range of the polyurethane sponge layer surface and the wall surface of the pipe mold becomes larger, but if the displacement x is too large, Since an excessive compressive force is applied to the polyurethane sponge layer on the side opposite to the peeling portion and the polyurethane sponge layer itself may be destroyed, if the polyurethane sponge layer has a thickness of 70% or less, the polyurethane sponge layer itself Will not be destroyed. The thickness of the polyurethane sponge layer is a value obtained by subtracting the radius of the core metal from the radius of the polyurethane sponge roller. If the displacement amount x is smaller than 20%, the displacement amount x is too small, so that the surface of the polyurethane sponge layer and the wall surface of the pipe mold are not sufficiently separated. In some cases, a large load is applied to the surface of the polyurethane sponge layer that is not covered, and the surface of the polyurethane sponge layer may be torn.

  In particular, when the length of the polyurethane foam layer is long, such as the length of the polyurethane sponge layer is 250 mm or more and 350 mm or less, the load at the time of demolding is likely to increase, and the polyurethane foam layer surface is torn or cracked. When the length of the urethane foam layer in the longitudinal direction is long, the method for producing a polyurethane sponge roller of the present invention is particularly effective.

  In the toner supply roller, it is desired that the toner is taken in from the surface of the elastic (polyurethane sponge) layer and the toner taken in the elastic layer is uniformly supplied to the surface of the developing roller. The surface condition greatly affects the image performance. For this reason, it is important not to cause minute tears or cracks on the surface of the elastic layer of the toner supply roller, and it is effective to use the method for producing a polyurethane sponge roller of the present invention. In particular, it can be suitably used for manufacturing a toner supply roller that rotates in contact with the surface of the developing roller and supplies toner to the surface of the developing roller in the developing mechanism portion of an electrophotographic apparatus or an electrostatic recording apparatus.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. Needless to say, the present invention is not limited by the description of the embodiments.

  In practice, a polyurethane sponge roller having the shape shown in FIG. 1 was molded. The outer diameter of the polyurethane sponge layer of the polyurethane sponge roller is φ18 (mm), and the length of the polyurethane sponge layer portion is 340 mm.

  The materials, molding conditions, and molding procedures of the polyurethane sponge roller molded in Examples and Comparative Examples are shown below.

First, the material used for molding will be described. As a mixed polyol, 100 parts by weight of FA-908, 0.5 parts by weight of diethanolamine, 1 part by weight of L5366, 0.1 part by weight of ToyoCat-ET, 0.5 part by weight of TEDA-L33, water (foaming agent) 2 parts by weight were prepared and mixed. The FA-908 is a polyether polyol manufactured by Sanyo Chemical Co., Ltd. L5366 is a silicone-based foam stabilizer manufactured by Nippon Unicar Co., Ltd. The ToyoCat-ET is a tertiary amine catalyst manufactured by Tosoh Corporation. The TEDA-L33 is a tertiary amine catalyst manufactured by Tosoh Corporation. Then, TCO (Mitsui Takeda Chemical Co., Ltd. isocyanate, NCO% = 48) 29.5 parts by weight, M200 (Mitsui Takeda Chemical Co., Ltd. isocyanate, NCO% = 31) 7.4 parts, so that NCO index 100 The material mixed and stirred was used as a polyurethane sponge material. Next, the molding procedure will be described. A silicone oil release agent is applied to a molding die composed of a pipe die, upper piece, and lower piece, and a φ7 × 360mm (L) core metal, upper piece, and lower piece are assembled to the pipe die. And preheated to 65 ° C. Thereafter, the foamed material that was mixed and stirred was placed in a mold that was assembled, and the mold cavity was filled. The density of the sponge foam material is 0.1 g / cm ³ .

  Then, it was cured in a hot plate controlled at 65 ° C. for 10 minutes, and the upper piece and the lower piece were removed, and the state shown in FIG. 2 constituted by a pipe mold, a molded polyurethane sponge layer and a cored bar was obtained.

  Next, the demolding method of an Example and a comparative example is demonstrated.

  The amount of displacement of the mold shown below is the amount of displacement between the central axis of the core metal and the central axis of the pipe mold expressed as a ratio (%) to the thickness of the polyurethane sponge layer. is there.

Example 1
From the state shown in FIG. 2, gripping both ends of the cored bar, a force perpendicular to the cored bar axis is applied to the pipe mold, and the angle direction is a four-direction angle obtained by dividing a circle about the cored bar axis approximately evenly. From the direction, the amount of displacement was 20%, and the surface of the polyurethane sponge roller was peeled from the inner surface of the mold, and then the polyurethane roller was pulled out.

(Example 2)
From the state shown in FIG. 2, gripping both ends of the cored bar, a force perpendicular to the cored bar axis is applied to the pipe mold, and the angle direction is a four-direction angle obtained by dividing a circle about the cored bar axis approximately evenly. From the direction, the amount of displacement was 45%, the surface of the polyurethane sponge roller was peeled from the inner surface of the mold, and the polyurethane roller was pulled out.

(Example 3)
From the state shown in FIG. 2, gripping both ends of the cored bar, a force perpendicular to the cored bar axis is applied to the pipe mold, and the angle direction is a four-direction angle obtained by dividing a circle about the cored bar axis approximately evenly. From the direction, the amount of displacement was 70%, and the surface of the polyurethane sponge roller was peeled from the inner surface of the mold, and then the polyurethane roller was pulled out.

Example 4
From the state shown in FIG. 2, the angle in six directions is obtained by grasping both ends of the core metal, and applying a force perpendicular to the core metal axis to the pipe mold so that the angle direction divides the circle centered on the core metal axis substantially evenly. From the direction, the amount of displacement was 45%, the surface of the polyurethane sponge roller was peeled from the inner surface of the mold, and the polyurethane roller was pulled out.

(Example 5)
From the state shown in FIG. 2, an angle in 8 directions obtained by grasping both ends of the core metal and applying a force perpendicular to the core metal axis to the pipe mold so that the angle direction is substantially evenly divided into a circle centered on the core metal axis. From the direction, the amount of displacement was 45%, the surface of the polyurethane sponge roller was peeled from the inner surface of the mold, and the polyurethane roller was pulled out.

(Comparative Example 1)
From the state shown in FIG. 2, gripping both ends of the cored bar, the pipe mold, the force perpendicular to the cored bar axis from the angle direction of one direction with respect to the circle whose center is the cored bar axis, In addition to the displacement amount being 45%, the surface of the polyurethane sponge roller was peeled off from the inner surface of the mold, and then the polyurethane roller was pulled out.

(Comparative Example 2)
From the state shown in FIG. 2, two end angles are obtained by gripping both ends of the core metal, and applying a force perpendicular to the core metal axis to the pipe mold so that the angular direction divides the circle centered on the core metal axis substantially evenly. From the direction, the amount of displacement was 45%, the surface of the polyurethane sponge roller was peeled from the inner surface of the mold, and the polyurethane roller was pulled out.

(Comparative Example 3)
From the state shown in FIG. 2, two end angles are obtained by gripping both ends of the core metal, and applying a force perpendicular to the core metal axis to the pipe mold so that the angular direction divides the circle centered on the core metal axis substantially evenly. From the direction, the amount of displacement was 70%, and the surface of the polyurethane sponge roller was peeled from the inner surface of the mold, and then the polyurethane roller was pulled out.

(Comparative Example 4)
From the state shown in FIG. 2, the angle in three directions is obtained by grasping both ends of the core metal and applying a force perpendicular to the core metal axis to the pipe mold so that the angle direction is substantially evenly divided into a circle centered on the core metal axis. From the direction, the amount of displacement was 45%, the surface of the polyurethane sponge roller was peeled from the inner surface of the mold, and the polyurethane roller was pulled out.

(Comparative Example 5)
From the state shown in FIG. 2, the angle in three directions is obtained by grasping both ends of the core metal and applying a force perpendicular to the core metal axis to the pipe mold so that the angle direction is substantially evenly divided into a circle centered on the core metal axis. From the direction, the amount of displacement was 70%, and the surface of the polyurethane sponge roller was peeled from the inner surface of the mold, and then the polyurethane roller was pulled out.

(Comparative Example 6)
From the state shown in FIG. 2, gripping both ends of the cored bar, a force perpendicular to the cored bar axis is applied to the pipe mold, and the angle direction is a four-direction angle obtained by dividing a circle about the cored bar axis approximately evenly. From the direction, the amount of displacement was 90%, the surface of the polyurethane sponge roller was peeled from the inner surface of the mold, and the polyurethane roller was pulled out.

(Appearance evaluation)
100 polyurethane rollers produced in Examples and Comparative Examples were produced, the surface of the polyurethane roller was torn visually, only the cracks were observed, and the number of occurrences was counted.

  Table 1 shows the displacement conditions and the occurrence rate of cracks and cracks in Examples 1 to 5.

  Table 2 shows the displacement conditions and the incidence of cracks and cracks in Comparative Examples 1-6.

  The polyurethane sponge roller molded in Examples 1 to 5 was not broken and cracked in the polyurethane sponge layer of the removed polyurethane sponge roller, and a good polyurethane sponge roller was obtained.

  In Comparative Example 1, the area of the part of the polyurethane sponge roller where the surface of the polyurethane sponge roller was not peeled from the inner surface of the mold was large, and the polyurethane sponge roller of the removed polyurethane sponge roller was torn and cracked frequently.

  The polyurethane sponge roller molded in Comparative Example 2 had a large area where the surface of the polyurethane sponge roller was not peeled off from the inner surface of the mold, and the surface of the polyurethane sponge layer of the removed polyurethane sponge roller was torn and cracked.

  The polyurethane sponge roller molded in Comparative Example 3 has a sufficient amount of displacement, but there is a portion where the surface of the polyurethane sponge roller is not peeled off from the inner surface of the mold, and it tears into the surface of the polyurethane sponge layer of the removed polyurethane sponge roller. Cracking occurred.

  The polyurethane sponge roller molded in Comparative Example 4 had an area where the surface of the polyurethane sponge roller was not peeled off from the inner surface of the mold, and a minute tear or crack occurred on the surface of the polyurethane sponge layer of the removed polyurethane sponge roller. .

  The polyurethane sponge roller molded in Comparative Example 5 has a sufficient amount of displacement, but there are some portions where the surface of the polyurethane sponge roller is not peeled off from the inner surface of the mold, and the surface of the polyurethane sponge layer of the removed polyurethane sponge roller is very small. Cracks and cracks occurred.

  Since the polyurethane sponge roller molded in Comparative Example 6 has a displacement amount that is too large, a minute tear occurred on the surface of the polyurethane sponge layer of the removed polyurethane sponge roller.

  When a polyurethane sponge roller having a surface of the polyurethane sponge layer in the comparative example having a tear or crack is used as the toner supply roller, uneven density or white color may be lost on the image.

It is a schematic diagram of the elastic roller shape | molded by this implementation. It is sectional drawing of the pipe die and elastic roller of the state before applying the demolding method of this invention. It is sectional drawing which shows the pipe metal mold | die at the time of the displacement which is the demolding method process of this invention, and an elastic layer state. It is sectional drawing which shows the pipe metal mold | die at the time of displacement rotation which is a demolding method process of this invention, and an elastic layer state. It is sectional drawing which shows the state at the time of elastic roller extrusion which is a demolding method process of this invention.

Explanation of symbols

1: Core metal 2: Polyurethane sponge layer 3: Pipe mold 4: Shaft
x: Displacement

Claims (3)

In a method for producing a polyurethane sponge roller, which is cured around a cored bar preliminarily disposed in a mold, after the polyurethane material is foamed and cured in the mold, the cored bar is gripped and fixed to the mold. A force substantially perpendicular to the axis of the core metal is applied from four or more angular directions of the circumference of the axis obtained by dividing a circle centered on the axis substantially evenly, and the surface of the polyurethane sponge roller is applied to the surface of the polyurethane sponge roller. After the step of peeling from the inner surface of the mold, the polyurethane sponge roller is manufactured through a step of demolding,
A method for producing a polyurethane roller, wherein the amount of displacement of the mold due to the force applied to the mold in the peeling step is 20% or more and 70% or less of the thickness of the polyurethane sponge layer.   2. The method for producing a polyurethane sponge roller according to claim 1, wherein the length of the polyurethane sponge layer of the polyurethane sponge roller in the longitudinal direction is from 250 mm to 350 mm.   A toner supply roller comprising a polyurethane sponge roller manufactured by the method of manufacturing a polyurethane sponge roller according to claim 1, wherein the toner supply roller is in contact with the surface of the developing roller at a developing mechanism portion of an electrophotographic apparatus or an electrostatic recording apparatus. A toner supply roller which rotates and supplies toner to the surface of the developing roller.

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