JP2002113727A - Method for manufacturing polyurethane foam roller and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a homogenous polyurethane foam roller suppressed from the involution of air, reduced in the irregularity of density or a cell size and having excellent quality. SOLUTION: A polyurethane foam forming material is foamed and cured in a cylindrical mold to manufacture a roller having a shaft and the polyurethane foam layer provided on the outer periphery of the shaft. The volume of the foaming zone in the cylindrical mold is continuously increased in conformity to the foaming expansion speed of the material and the foaming zone is filled with foam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a polyurethane foam roller and an image forming apparatus. More specifically, the present invention relates to a polyurethane foam roller, in particular, a toner supply roller, which suppresses air entrainment and has a small variation in density (hardness) and cell size, and is uniform and excellent in quality. TECHNICAL FIELD The present invention relates to a method for efficiently producing a toner using the same, and an image forming apparatus provided with a polyurethane foam roller obtained by the method.

[0002]

2. Description of the Related Art In recent years, with the development of electrophotographic technology, image forming apparatuses such as dry electrophotographic apparatuses have been used for charging, developing, and the like.
Polymer members have attracted attention as members of parts used for transfer, toner supply, cleaning, paper supply, and the like, and generally, a charging roller, a developing roller, a transfer roller, a toner supply roller, and a cleaning roller And a roller having elasticity such as a paper feed roller.
For the polymer members used for these purposes, polymer elastomers or foams such as rubber or polyurethane are usually used, and these have low hardness and do not contaminate image forming bodies and transfer materials. Is required.

However, in order to reduce the hardness of rubber or polyurethane elastomers, it is necessary to incorporate a plasticizer such as dioctyl phthalate or an oil such as aroma oil, and as a result, does not contaminate the image forming body. It is difficult to meet the demand. Therefore, a foam obtained by foaming ethylene-propylene-diene rubber (EPDM) or silicone rubber with a foaming agent such as 4,4'-oxybis (benzenesulfonylhydrazide), or a polyurethane foamed with a foaming agent such as water or Freon is used. Advantageously, foams are used, in particular polyurethane foams.

As a method for producing this polyurethane foam, for example, a polyol component, a polyisocyanate component,
A foam-forming material containing a physical foaming agent and optionally a conductivity-imparting agent or a urethane reaction catalyst is poured into a mold having a predetermined shape in which a shaft is set and foam-cured, or freely in a block shape. After foaming, heat and cure,
A method is known in which a block is cut out from a block to a predetermined size by cutting, and a shaft is attached.

[0005] Among these methods, a method using a cylindrical mold as a mold is often used because a polishing treatment is not necessarily required after the mold is released. As a method of manufacturing a polyurethane foam roller using this cylindrical mold, for example, a method is known in which a cylindrical mold having a shaft set therein is set upright and a polyurethane foam forming material is injected from an upper opening. I have. However, in this method, since the opening is narrow and there is a distance to the bottom, the foam-forming material starts foaming before reaching the bottom, and the molded product has an unfilled portion or air. It tends to be inferior in quality, such as the formation of voids due to entanglement. In addition, a method is known in which an injection port is provided at the bottom and a polyurethane foam forming material is press-fitted with an injection nozzle. In this case, since foam expands and expands along a shaft in a mold, air entrapment is suppressed. However, countermeasures such as prevention of backflow to the injection port after injection and prevention of contamination of the vicinity of the injection port with the cured polyurethane are particularly difficult in an automated production line or a high-speed production line. Furthermore, when filling the space from the bottom to the top of the cylinder while the material expands and expands, the friction between the shaft and the inner surface of the mold causes the upper and lower parts of the foam to rise through the narrow gap against the weight. Therefore, there is a problem that a density difference (hardness difference) and a non-uniform cell size occur. In order to solve such a problem, measures such as laying down a cylindrical mold after injecting the foam-forming material have been attempted. However, air entrainment, unevenness in density (hardness) and cell size have been attempted. In fact, such problems have not been sufficiently solved.

[0006]

Under such circumstances, the present invention suppresses the formation of voids due to the entrainment of air, reduces the variation in density (hardness) and cell size, and provides uniform and high quality. It is an object of the present invention to provide a method for efficiently producing an excellent polyurethane foam roller, particularly a polyurethane foam roller suitable as a toner supply roller used in an image forming apparatus, using a cylindrical mold.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, the expansion zone of the foaming zone in the cylindrical mold was adjusted in accordance with the expansion rate of the polyurethane foam forming material. It has been found that by continuously increasing the volume, its purpose can be achieved. The present invention
It has been completed based on such knowledge.

That is, according to the present invention, a polyurethane foam-forming material is foamed and cured in a cylindrical mold to form a shaft,
In producing a roller having a polyurethane foam layer provided on its outer periphery, the volume of the foaming zone in the cylindrical mold is continuously increased in accordance with the foaming expansion rate of the material, and the foaming zone is foamed. An object of the present invention is to provide a method for producing a polyurethane foam roller characterized by being filled with a body.

Further, a preferred aspect of the present invention is that (1) a shaft is set at the center of the opening of a cylindrical mold, and the upper part of the shaft is moved in close contact with the inner surface of the mold and the shaft. A movable piece which can be mounted, and a polyurethane foam-forming material is injected from the opening into the gap formed by the piece, the shaft and the inner surface of the mold, and then the opening is covered to start foaming. A method for manufacturing a polyurethane foam roller by removing the mold after the movable piece moves down and the cavity in the mold is filled with the foam together with foaming expansion of the material, and then cured and removed (hereinafter, referred to as
This is referred to as a production method I of the present invention. (2) With the opening of the cylindrical mold facing upward, and in the center of the upper part,
A shaft having a fixed top that can be in close contact with the inner surface of the mold is set so that the upper end of the shaft is higher than the opening, and an opening is formed in a gap formed by the top, the shaft, and the inner surface of the mold. At the same time as the foaming was started by injecting the polyurethane foam forming material from the portion, the cylindrical mold was raised while being in close contact with the top in accordance with the foaming expansion rate of the material, and the cavity in the mold was filled with the foam. Then, a method of manufacturing a polyurethane foam roller by covering the opening with a lid and curing, and then removing the mold (hereinafter referred to as the manufacturing method II of the present invention)
Called. ) And (3) with the cylindrical mold opening up,
At the center of the upper part, a shaft with a fixed top that can be in close contact with the inner surface of the mold is set at the lower end so that the upper end of the shaft is higher than the opening, and a column that supports it is set below the top. Then, a polyurethane foam-forming material is injected from the opening into the gap formed by the top, the shaft, and the inner surface of the mold to start foaming, and at the same time, the column is lowered in accordance with the foaming expansion rate of the material. Then, after the shaft is moved downward together with the top to fill the cavity inside the mold with foam, the opening is covered and cured, and then the mold is removed to produce a polyurethane foam roller (hereinafter referred to as a method). , Referred to as the production method III of the present invention). Further, the present invention also provides an image forming apparatus equipped with the polyurethane foam roller obtained by the above-mentioned manufacturing method.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the method for producing a polyurethane foam roller according to the present invention, as a polyurethane foam forming material, a polyol component, a polyisocyanate component, a foaming agent and, if desired, a conductivity-imparting agent, a catalyst, and a foam stabilizer are used. Those containing an agent or the like are used. In the polyurethane foam-forming material, the polyol component and the polyisocyanate component may be contained in the form of a prepolymer obtained by reacting them.

The polyol component used for producing the polyol or the prepolymer is not particularly limited, and examples thereof include a polyether polyol, a polyester polyol, and a hydrophobic polyol. Here, as the polyether polyol, a polyol obtained by addition-polymerizing ethylene oxide or propylene oxide to glycerin or the like, or a polyol such as polytetramethylene glycol, ethylene glycol, propanediol, or butanediol is preferably used. As the polyester polyol, a condensation-based polyester polyol obtained by condensation of a dicarboxylic acid and a diol or a triol, a lactone-based polyester polyol obtained by ring-opening polymerization of a lactone based on a diol or a triol, and a polyether polyol having a lactone terminal. A polyol such as an ester-modified ester-modified polyol is preferably used. Further, as the hydrophobic polyol, polyisoprene polyol, polybutadiene polyol, hydrogenated polybutadiene polyol, or the like is used. These polyol components may be used alone or in combination of two or more.

On the other hand, the polyisocyanate component used for producing a polyisocyanate or a prepolymer includes tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate (crude MDI), isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate; Examples include hydrogenated tolylene diisocyanate; polyisocyanates having no unsaturated bond such as hexamethylene diisocyanate, and modified products thereof with isocyanurate, carbodiimide, glycol, and the like. These polyisocyanate components may be used alone or in combination of two or more.

Next, as the foaming agent, taking into account ease of handling in the production process, ease of vaporization and foaming, etc.,
Generally, a physical foaming agent having a boiling point in the range of 20 to 60 ° C is preferably used. When this foaming agent is used as a raw material of a polyurethane foam, it is difficult to obtain a stable flow rate by using a foaming agent alone and to obtain a stable flow rate with a foaming machine. It is advantageous. Examples of such a foaming agent include n-pentane, isopentane, cyclopentane, methylene chloride, Freon 134a (1,1,1,2-tetrafluoroethane), and Freon 245fa (1,1,1,1).
3,3-pentafluoropropane), CFC 365mf
c (1,1,1,3,3-pentafluorobutane), Freon 356, Freon 141b (1,1-dichloro-1-
Fluoroethane), Freon 142b (1-chloro-1,
1-difluoroethane), Freon 22 (chlorodifluoromethane), and water. These may be used alone or in combination of two or more.

Next, in the polyurethane foam-forming material of the present invention, examples of the conductivity-imparting agent to be used include carbon black and ionic conductive agents. Examples of carbon black include gas black such as electrified black, Ketjen black, and acetylene black, oil furnace black including ink black, thermal black, channel black, and lamp black. As the ion conductive agent,
For example, tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium such as lauryltrimethylammonium, octadecyltrimethylammonium such as stearyltrimethylammonium,
Perchlorates, chlorates, hydrochlorides, bromates, such as hexadecyltrimethylammonium, benzyltrimethylammonium, modified aliphatic dimethylethylammonium,
Ammonium salts such as iodate, borofluoride, sulfate, alkyl sulfate, carboxylate and sulfonate; perchlorates of alkali metals or alkaline earth metals such as lithium, sodium, calcium and magnesium Chlorate, hydrochloride, bromate, iodate, borofluoride, trifluoromethyl sulfate, sulfonate and the like.

These conductivity-imparting agents may be used alone or in combination of two or more. The amount is not particularly limited and is appropriately selected according to various situations. Usually, the amount is 0.1 to 100 parts by weight of the polymer material.
４０40 parts by weight, preferably 0.3-20 parts by weight. In addition, a filler-based conductive agent such as a metal powder and a metal oxide powder can be added together with the carbon black and the ionic conductive agent. In the polyurethane foam-forming material, as a catalyst optionally used, for example, organometallic catalysts such as dibutyltin dilaurate, dibutyltin diacetate, stannas octoate, dibutyltin marker butide, dibutyltin thiocarboxylate, and dibutyltin dimaleate Neat, dioctyltin marker butide, dioctyltin thiocarboxylate, phenylmercury, silver propionate, tin octenoate, amine-catalyzed triethylamine, N, N, N'N'-tetramethylethylenediamine, triethylenediamine, N
-Methylmorpholine, dimethylaminoethanol, bis (2-dimethylaminoethyl) ether, 1,8-diazabicyclo (5,4,0) -undecene-7 and the like are preferably used. These catalysts may be used alone,
Two or more kinds may be used in combination.

Further, in the polyurethane foam-forming material, as the foam stabilizer optionally used, for example, polyether silicone oil, nonionic surfactant, ionic surfactant and the like can be mentioned. Or two or more of them may be used in combination.
In the method for producing a polyurethane foam roller of the present invention, the polyurethane foam-forming material is foamed and cured in a cylindrical mold to produce a roller having a shaft and a polyurethane foam layer provided on the outer periphery thereof. . And in the production of this polyurethane foam roller,
A method is used in which the volume of the foaming zone in the cylindrical mold is continuously increased in accordance with the expansion rate of the foam-forming material, and the foaming zone is filled with foam. By using such a method, defects such as void formation due to entrainment of air, non-uniformity of density (hardness) and cell size, which were disadvantages in the conventional technique of manufacturing a polyurethane foam roller using a cylindrical mold, were obtained. Can be avoided.

Preferred embodiments of the method of the present invention include the following production method I, production method II and production method III. First, the manufacturing method I of the present invention will be described. FIG. 1 is a process diagram for explaining an example of the manufacturing method I of the present invention. In the manufacturing method I, first, the opening of the cylindrical mold 1 is turned upward, and the shaft 2 is set at the center thereof. At the same time, the movable piece 3 is mounted on the upper part of the shaft 2 (FIG. 1A).
The movable piece 3 is not particularly limited as long as it can easily move in the longitudinal direction of the cylinder inner surface with a small force in close contact with the inner surface of the mold and the shaft.
Any of metal and plastic can be used.

Next, a polyurethane foam forming material 6 is injected into the gap formed by the movable piece 3, the shaft 2, and the inner surface of the cylindrical mold 1 through the opening [FIG. 1 (b)]. Next, the opening is covered with the upper lid 4 and foaming is started at a temperature usually in the range of 15 to 80 ° C., preferably 20 to 65 ° C., so that the movable piece 3 is expanded by the foaming pressure together with the foaming expansion of the material. Moves downward, and the cavity in the mold is filled with the polyurethane foam 7 [FIG. 1 (c)]. Next, 7
After curing at a temperature of about 0 to 120 ° C., the mold is removed from the mold, the movable piece 3 is removed, and cut into desired dimensions.
The desired polyurethane foam roller 10 is obtained [FIG.
(D)]. In addition, 5 is a lower lid.

Next, the production method II of the present invention will be described. FIG. 2 is a process chart for explaining an example of the manufacturing method II of the present invention. In the manufacturing method II, first, the opening of the cylindrical mold 1 is turned upward, and a cylindrical shape is placed at the center of the upper part. A shaft 2 having a fixed top 3 'attached to the lower end thereof which can be in intimate contact with the inner surface of the mold 1 is set so that the upper end of the shaft 2 is higher than the opening. The polyurethane foam forming material 6 is injected into the void formed between the inner surface of the mold 1 and the opening through the opening, and foaming is started at the same temperature as in the manufacturing method I (FIG. 2A). Next, simultaneously with the start of foaming, the cylindrical mold 1 is raised while being in close contact with the fixed top 3 ′ in accordance with the foaming expansion rate of the above-mentioned material, and after filling the cavity in the mold with the polyurethane foam 7,
The opening is covered with an upper cover 3 (FIG. 2B). Next, 70
After curing at a temperature of about 120 ° C., the resulting polyurethane foam roller is obtained by demolding and cutting to a desired size. In addition, 5 is a lower lid.

Finally, the production method III of the present invention will be described. FIG. 3 is a process diagram for explaining an example of the production method III of the present invention. In the production method III, first, the opening of the cylindrical mold 1 is turned upward,
A shaft 2 having a fixed top 3 'attached to the lower end capable of closely contacting the inner surface of the cylindrical mold 1 is set so that the upper end of the shaft 2 is higher than the opening, and the fixed top 3' is set.
Set the support column 8 that supports it under [Fig.
(A)]. Next, the polyurethane foam forming material 6 is injected into the gap formed by the fixed top 3 ′, the shaft 2 and the inner surface of the cylindrical mold 1 from the opening, and foaming is performed at the same temperature as in the above-mentioned production method I. Simultaneously, the shaft 2 is moved downward together with the fixed piece 3 'by lowering the column 8 in accordance with the foaming and expansion speed of the material [FIG. 3 (b)]. Next, after filling the void in the mold with the polyurethane foam 7, the opening is covered with the upper lid 4 [FIG.
(C)], curing at a temperature of about 70 to 120 ° C.,
Then, the resulting polyurethane foam roller is obtained by removing the mold and cutting it into a desired size.

The polyurethane foam roller obtained by such a method of the present invention has a foam layer in which voids are not formed due to entrainment of air, cell size is uniform, and density (hardening) variation is small. And have excellent quality. The material of the cylindrical mold used in the method of the present invention is not particularly limited, and a metal or resin material conventionally used in the production of a polyurethane foam roller can be used. S
US) are preferred.

If necessary, a coating layer made of a fluororesin or the like may be provided on the inner surface of the cylindrical mold, or a known silicone-based or fluorine-based release agent may be applied. Further, as the shaft constituting the polyurethane foam roller in the method of the present invention, for example, a metal member obtained by plating a steel material such as sulfur free-cutting steel with zinc or the like, or a metal member such as aluminum, stainless steel, steel, or a magnesium alloy. No. In the above-described manufacturing methods I, II and III of the present invention, the movable top removed after the mold release and the fixed top separated from the shaft can be reused by selecting a material.

The polyurethane foam roller manufactured by the method of the present invention can be used for various members for an image forming apparatus such as an electrophotographic apparatus and an electrostatic recording apparatus, for example, a charging roller, a developing roller, a transfer roller, a toner supply roller, and a cleaning roller. Although it can be used as a roller and a paper feed roller, it is particularly suitable as a toner supply roller. Further, the image forming apparatus of the present invention is obtained by mounting the polyurethane foam roller obtained by the above-described method of the present invention as the various members described above.

Next, an example in which the polyurethane foam roller is mounted on an image forming apparatus as a toner supply roller will be described. FIG. 4 is an explanatory view showing an example of an electrophotographic image forming apparatus in which the polyurethane foam roller obtained by the method of the present invention is mounted as a toner supply roller. A developing roller 12 is disposed between the developing roller 12 and the image forming body 11 holding the electrostatic latent image in a state where the outer peripheral surface thereof is close to the surface of the image forming body 11, and a recording medium such as paper is provided on the image forming body 11. 18 shows a structure in which the transfer roller 15 is in contact with the transfer roller 18. Toner supply roller 13, developing roller 12, and image forming body 1
1 is rotated in the direction of the arrow to supply toner to the surface of the developing roller 12 by the toner supply roller 13, and the toner is adjusted to a uniform thin layer by the layer regulating blade 14. And the latent image is visualized. Then, by generating an electric field between the image forming body 11 and the transfer roller 15, the toner image on the image forming body 11 is transferred to the recording medium 18. Also, 16
Reference numeral denotes a cleaning roller. The cleaning roller 16 removes toner remaining on the surface of the image forming body 11 after transfer. Reference numeral 17 denotes a charging roller.

[0025]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Preparation Example 1 70 parts by weight of a polyether polyol having an average molecular weight of 5,000 and a number of functional groups of 3; 30 parts by weight of a styrene graft type polymer polyol;
3 parts by weight, 0.2 part by weight of N-methylmorpholine,
1.5 parts by weight of water, 1.5 parts by weight of silicone foam stabilizer and the ratio of TDI-80 / polymeric MDI is 50/5
A polyurethane foam-forming material was prepared by blending an iriocyanate of 0 in such an amount as to give an index of 105. In a free foaming experiment in a cup, which was separately performed, the polyurethane foam-forming material started foaming at 25 ° C. for 10 seconds after stirring and pouring, and completed foaming in 90 seconds. The density at that time was 0.10 g / milliliter.

Example 1 (Production of Polyurethane Foam Roller by Production Method I) A SUS cylinder having an inner diameter of 18 mm and a length of 250 mm, a diameter of 6 m
m, an iron shaft having a length of 260 mm, an upper lid and a lower lid provided with a shaft holding hole at the center. First, SU
A lower lid was attached to one opening of the S-made cylinder, and a cylindrical mold was set up with a shaft inserted into a shaft holding hole of the lower lid. Then, with a thickness of 10 mm and an outer diameter of 18.8 mm,
A movable piece made of polyurethane foam, which has a hole of 5.8 mm in diameter and through which the shaft can penetrate and is movable in the mold, is mounted on the shaft, and the upper surface of the movable piece is 40 mm below the cylindrical opening. It was set to be located.

Next, 6.5 g of the polyurethane foam-forming material obtained in Preparation Example 1 was injected into a space formed by the cylindrical inner surface, the shaft and the movable piece from a foaming machine, and the upper lid was immediately inserted into the shaft holding hole. The shaft was fitted into a cylindrical opening so that the end of the shaft could enter. After the upper lid is attached, the material starts foaming and expands while pushing down the movable piece with the foaming pressure,
It is assumed that the inside of the mold was filled with the foam in about 90 seconds at a temperature of about 25 ° C. Thereafter, the mixture was cured at 90 ° C. for 20 minutes, then released from the mold, and the movable piece was removed and cut to obtain a polyurethane foam roller with a shaft having a diameter of 18 mm and a length of 220 mm. The foam layer of this roller did not form voids due to the entrainment of air, had a uniform cell size as a whole, and had little variation in density. The results are shown in Table 1.

Example 2 (Production of Polyurethane Foam Roller by Production Method II) A SUS cylinder having an inner diameter of 18 mm and a length of 250 mm, and a fixed piece made of a polyurethane foam having a thickness of 10 mm and an outer diameter of 18.8 mm attached to a lower end of 6 mm. An iron shaft having a length of 260 mm, a lower lid, and an upper lid having a shaft holding hole in the center were prepared. First, a cylindrical type having a lower lid attached to one opening of a SUS cylinder is set up, and then, from the opening of the cylindrical type, a shaft with a fixed top attached at the lower end is inserted from the fixed top side, and the fixed type is fixed. The top of the top is 40 from the opening
mm. Next, 6.5 g of the polyurethane foam forming material obtained in Preparation Example 1 was injected from a foaming machine into a space formed by the cylindrical inner surface, the shaft, and the fixed top. Next, at the same time as the foaming is started, the cylindrical mold is raised in accordance with the foaming and expanding speed of the above-mentioned material (at substantially the same speed as the foaming and expanding speed) while keeping its inner surface in close contact with the fixed top, and at a temperature of about 25 ° C, The mold was filled with a foam in about 90 seconds. After that, the upper lid was attached to the cylindrical opening so that the end of the shaft was inserted into the shaft holding hole, cured at 90 ° C. for 20 minutes, then removed from the mold, cut and cut to a diameter of 18 mm and a length of 220 mm. A polyurethane foam roller with a shaft was produced. The foam layer of this roller did not form voids due to the entrainment of air, had a uniform cell size as a whole, and had little variation in density. The results are shown in Table 1.

Example 3 (Production of Polyurethane Foam Roller by Production Method III) A SUS cylinder having an inner diameter of 18 mm and a length of 250 mm, and a fixed piece made of polyurethane foam having a thickness of 10 mm and an outer diameter of 18.8 mm attached to a lower end of 6 mm. An iron shaft having a length of 260 mm, an upper lid provided with a shaft holding hole at the center, and a SUS column having a diameter of 10 mm and a length of 350 mm were prepared.

First, from one opening of the SUS cylinder,
Insert the shaft with the fixed top at the lower end from the fixed top side, set it so that the upper surface of the fixed top is located 40 mm below the opening, and set the column supporting the top under the fixed top, A cylindrical mold was set up so that the opening was upward. Next, 6.5 g of the polyurethane foam forming material obtained in Preparation Example 1 was injected from a foaming machine into a space formed by the cylindrical inner surface, the shaft, and the fixed top. Then, simultaneously with the start of foaming, the shaft is moved downward together with the fixed piece by pulling down the column in accordance with the foaming and expanding speed of the material (at substantially the same speed as the foaming and expanding speed). The top was allowed to reach the lower end of the cylindrical mold, and the inside of the mold was filled with a foam. The foaming temperature at this time is about 25
° C. Then, after attaching the upper lid to the cylindrical opening so that the end of the shaft enters the shaft holding hole,
The mixture was cured at 90 ° C. for 20 minutes, then removed from the mold, and cut to prepare a polyurethane foam roller with a shaft having a diameter of 18 mm and a length of 220 mm. The foam layer of this roller
No voids were formed due to the entrainment of air, the cell size was uniform throughout, and there was little variation in density. The results are shown in Table 1.

Comparative Example 1 In Example 1, a movable foam was not used, and a polyurethane foam-forming material was directly injected from a cylindrical opening to foam the foam. After the foam was filled in the mold, Operations were performed in the same manner as in Example 1 except that the upper lid was attached, to produce a polyurethane foam roller. Table 1 shows the properties of the foam layer in this roller. Comparative Example 2 A lower lid was attached to a SUS cylinder having the same dimensions as in Example 1, and after setting the shaft, an injection port having a diameter of 10 mm was provided at a position 40 mm above the bottom of the cylindrical mold. . This cylindrical mold was set up, 6.5 g of the polyurethane foam-forming material obtained in Preparation Example 1 was injected from the injection port, and a pre-threaded stopper was screwed into the injection port.
It was sealed so that the foaming liquid did not flow out. Thereafter, the same operation as in Example 1 was performed, and after the inside of the mold was filled with the foam, the upper lid was attached, and curing, demolding, and cutting were performed to produce a polyurethane foam roller. Table 1 shows the properties of the foam layer in this roller.

Comparative Example 3 SUS having the same dimensions and shaft holding structure as in Example 1
A split mold that can be divided in the length direction was prepared. First, after injecting 6.5 g of the polyurethane foam forming material obtained in Preparation Example 1 into the lower part of the split mold on which the shaft was set, the upper part of the split mold was attached, and the inside of the mold was filled with the foam. And sealed. Thereafter, operations were performed in the same manner as in Example 1, and curing, demolding, and cutting were performed to produce a polyurethane foam roller. Table 1 shows the properties of the foam layer in this roller.

[0033]

[Table 1]

(Note) 1) Density: In the foam layer of the foam roller, a point 10 mm away from the upper end during molding is defined as point A, a point 10 mm away from the lower end is defined as point C, and the center is defined as point B. ,
The respective densities were measured. 2) The cell size and hardness were different between the lower part and the upper part of the split mold.

[0035]

According to the present invention, the formation of voids due to the entrainment of air is suppressed, the density (hardness) and the variation in cell size are small, and a uniform and excellent polyurethane foam roller is efficiently obtained. Can be Polyurethane foam roller obtained by the method of the present invention, various members for image forming devices such as electrophotographic devices and electrostatic recording devices,
For example, it can be used as a charging roller, a developing roller, a transfer roller, a toner supply roller, a cleaning roller, a paper supply roller, and the like, and is particularly suitable as a toner supply roller.

[Brief description of the drawings]

FIG. 1 is a process chart of an example for explaining a method for producing a polyurethane foam roller of the present invention.

FIG. 2 is a process diagram of an example different from the above for describing a method for producing a polyurethane foam roller of the present invention.

FIG. 3 is a process diagram of still another example for explaining the method for producing a polyurethane foam roller of the present invention.

FIG. 4 is an explanatory diagram illustrating an example of the image forming apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical type 2 Shaft 3 Movable piece 3 'Fixed piece 4 Top lid 5 Lower lid 6 Polyurethane foam forming material 7 Polyurethane foam 8 Support post 10 Polyurethane foam roller 11 Image forming body 12 Developing roller 13 Toner supply roller 14 Layer regulation Blade 15 transfer roller 16 cleaning roller 17 charging roller 18 recording medium

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 75/04 C08L 75/04 3J103 F16C 13/00 F16C 13/00 A 4F202 E 4F204 G03G 15/02 101 G03G 15/02 101 4J002 15/08 501 15/08 501A 4J034 501D 15/16 103 15/16 103 21/10 (C08G 18/00 H // (C08G 18/00 101: 00) 101: 00) B29K 75: 00 B29K 75:00 105: 04 105: 04 B29L 31:32 B29L 31:32 G03G 21/00 312 (72) Inventor Wataru Takahashi 1 Kashio-cho, Totsuka-ku, Yokohama-shi, Kanagawa F-term in Bridgestone Yokohama Plant Reference) 2H003 BB11 CC05 2H032 AA05 BA19 BA23 2H034 BC03 2H077 AA15 AC04 AD06 FA22 3F343 FA02 FB01 JA11 3J103 AA02 E A02 FA15 FA30 GA02 GA52 HA03 HA12 HA18 HA48 4F202 AA42 AB02 AB13 AD03 AD15 AG20 AH04 AM32. DG04 DG06 HA01 HA07 HC03 HC12 HC17 HC64 HC71 HC73 NA01 NA03 QC01 QC03 RA11 RA14

Claims (8)

[Claims] In producing a roller having a polyurethane foam layer provided on a shaft and an outer periphery thereof, a polyurethane foam-forming material is foam-hardened in a cylindrical mold to adjust the foam expansion rate of the material. And continuously increasing the volume of the foaming zone in the cylindrical mold and filling the foaming zone with foam. 2. A shaft is set at the center of the cylindrical opening with the opening thereof facing upward, and an upper portion of the shaft is
A movable piece that can move in close contact with the inner surface of the mold and the shaft is mounted, and a polyurethane foam forming material is injected from the opening into a gap formed by the top, the shaft, and the inner surface of the mold,
Then, by closing the opening, by starting foaming, the foaming expansion of the above-mentioned material, the movable piece moves downward, and the cavity in the mold is filled with the foam, and after curing,
The production method according to claim 1, wherein the mold is released. 3. A shaft in which a fixed coma which can be in close contact with the inner surface of the mold is attached to a lower end of the shaft with the opening of the cylindrical mold facing upward, and the upper end of the shaft is higher than the opening. The polyurethane foam-forming material is injected from the opening into the cavity formed by the top, the shaft, and the inner surface of the mold to start foaming. 2. The production method according to claim 1, wherein the mold is lifted while being in close contact with the top, the cavity in the mold is filled with a foam, the opening is covered and cured, and then the mold is released. 4. A shaft in which a fixed piece that can be in close contact with the inner surface of the mold is attached to the lower end of the shaft with the opening of the cylindrical mold facing upward and the upper end of the shaft is higher than the opening. And a support for supporting the support is set below the top, and a polyurethane foam-forming material is injected from the opening into the gap formed by the top, the shaft, and the inner surface of the mold to start foaming. At the same time, the shaft is moved downward together with the top by pulling down the column in accordance with the foaming expansion rate of the material, filling the cavity in the mold with the foam, then covering the opening and curing after The production method according to claim 1, wherein the mold is removed. 5. The production method according to claim 1, wherein the polyurethane foam-forming material contains a polyol component, a polyisocyanate component, and a foaming agent. 6. The method according to claim 1, wherein the polyurethane foam roller is a conductive polyurethane foam roller. 7. The production method according to claim 6, wherein the polyurethane foam-forming material contains a polyol component, a polyisocyanate component, a foaming agent and a conductivity-imparting agent. 8. An image forming apparatus equipped with a polyurethane foam roller obtained by the method according to claim 1.