JP2002039162A - Manufacturing method for urethane sponge roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of easily and industrially advantageously manufacturing an urethane sponge roll having high roll dimension accuracy, surface cell open area ratio, and integrally having a sponge layer with uniform surface cell diameter. SOLUTION: A mold molded article 40 is prepared in which the sponge layer 42 made of soft polyurethane foam is integrally about a longitudinally bar-like core metal 36 and a skin layer is formed on the surface of the sponge layer 42 by mold molding operation. Then, plasma is radiated to the surface of the sponge layer 42 of the mold molded article 40 to melt and eliminate the skin layer existing on the sponge layer 42 surface, thereby opening a cell just under the skin layer for the outer peripheral surface to provide the desired urethane sponge roll.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a urethane sponge roll, and more particularly, to a toner supply roll, a development roll, a charging roll, a transfer roll, and a paper feeder in an image forming apparatus such as a copying machine, an image recording apparatus, a printer, and a facsimile. The present invention relates to a method for advantageously producing a urethane sponge roll which can be suitably used as a roll, a cleaning roll, and the like.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying apparatus, an image recording apparatus, a printer, and a facsimile, an electrostatic latent image formed on an image carrier made of an electrophotographic photosensitive member or an electrostatic recording dielectric is used. Developing with a toner (developer) supplied from a developing roll of a developing device and visualizing the toner image as a toner image has been performed. And a toner supply roll composed of a soft elastic roll for supplying the toner to the developing roll and further to the image carrier side, and further for transferring the formed toner image to transfer paper. Transfer rolls, paper feed rolls for supplying such transfer paper, charging rolls for charging the surface of the image carrier, removal of transfer residual images and residual toner on the surface of the image carrier To the cleaning roller or the like in order of the cleaning device, a predetermined elastic roll is used.

As one type of various types of elastic rolls used in such an image forming apparatus, a sponge layer of a predetermined thickness made of polyurethane foam is provided around a long bar-shaped core bar serving as a roll axis. Urethane sponge rolls have been proposed. For example, JP-A-3-155575 and JP-A-6-30
JP-A-1281 discloses a toner supply roll composed of a urethane sponge roll in which the cell diameter of the sponge layer and the number of cells per inch are specified, and JP-A-2-287576 and JP-A-2-287576. Kaihei 4-5
No. 5873, JP-A-7-36273, etc.
It has been clarified that a urethane sponge roll is used as a developing roll in a developing device. Further, Japanese Patent Application Laid-Open No. 5-35110 discloses a roll foaming used for a conductive roll used for the purpose of controlling an object electrostatically, such as a toner transport roll, a charging roll, a transfer roll, and a cleaning roll. As a method of manufacturing a body, a method has been disclosed in which a foamed sponge layer made of a polyurethane foam is integrally formed around the core by performing foam molding integrally with the core in a roll-shaped mold. .

[0004] By the way, this kind of urethane sponge roll is generally used as a surface porous roll in which a cell giving a sponge structure of the sponge layer is opened on the outer peripheral surface of the sponge layer. The urethane sponge roll proposed above is
A surface layer portion of a sponge layer made of polyurethane foam provided at a predetermined thickness around a cored bar, by high-speed rotation polishing using a grindstone, while obtaining the roll outer diameter, a method of opening the cell to the outside, Cutting using a hot wire such as a nichrome wire or using a rotating cylindrical blade or band knife as disclosed in JP-A-8-156144 and JP-A-10-104937. The cells of the sponge layer are opened on the outer peripheral surface by a method of cutting the sponge layer into a cylindrical shape, etc., and the target surface porous roll is obtained. Regardless of the roll of the product or the cut product, although there is an advantage that the opening ratio of the surface cell is increased, the size of the cell opening on the roll surface is
In addition to the problem of non-uniformity depending on the size of the cells inside the sponge layer, various problems corresponding to the respective processing methods are inherent.

[0005] For example, in the above-described method of obtaining a polished product (porous surface roll) by high-speed rotational polishing of the surface layer portion of the sponge layer, the sponge layer (polyurethane foam) becomes soft. As the sponge layer is deformed by the pressing action of the grindstone, it is difficult to obtain the accuracy of the roll dimensions, and a large amount of polishing dust is extremely difficult to handle when it is necessary to handle the roll as a precision member. It becomes troublesome, and it becomes necessary to thoroughly remove such polishing debris from the roll surface, which leads to an increase in the number of work steps and troublesome work.

[0006] Further, a method of obtaining a cut product (surface porous roll) by cutting (cutting) the surface layer portion of the sponge layer using a hot wire or a cutting tool to form a sponge layer having a circular outer peripheral surface. Although there is no problem of generation of fine cutting chips as in the high-speed rotation polishing method described above, as the sponge layer becomes softer, it is difficult to obtain roll dimensional accuracy, as described above, In order to maintain accuracy, the frequency of changing the cutting tool will inevitably increase,
This caused a problem in terms of cost.

Therefore, the applicant of the present application firstly
Japanese Patent Application Laid-Open No. 9-274373 discloses a toner supply roll and a method of manufacturing the toner supply roll.
50 g or less, having a skin layer forming a continuous smooth surface, forming a sponge layer made of a flexible polyurethane foam, and each cell located immediately below the skin layer has an opening diameter of 100 to 800 μm. A urethane sponge roll which is independently opened to the outside, and the entire area of the cells occupies 20% or more of the surface of the skin layer, and further, such a urethane sponge roll is formed into a molding cavity having a final roll shape. The production method is clarified by the foam molding operation (mold molding operation) of the polyurethane foam raw material in the
In Japanese Patent Application Laid-Open No. 11-37849, in the urethane sponge roll proposed in Japanese Patent Application Laid-Open No. 9-274373, the outer peripheral surface of the polyurethane foam layer (sponge layer) is provided so as to extend linearly in the roll axis direction. 20 to 3000 μm height and 300 mm
By a plurality of ridges having a pitch in the roll circumferential direction of up to 3000 μm, a urethane sponge roll characterized by having an uneven surface structure, and a method of manufacturing such a urethane sponge roll by a molding operation, Reveals.

However, according to the urethane sponge roll manufacturing method employing the molding method proposed by the applicant of the present application, the above-mentioned problem of polishing dust and roll dimensional accuracy can be completely eliminated. In order to independently open each cell of the surface layer of the sponge layer to the outside on the skin layer surface, it was necessary to provide an opening penetrating the skin layer, so there was an inevitable limit, for example, In the case of a urethane sponge roll having a smooth roll surface, the cell opening ratio on the surface of the sponge layer exceeds 70%, particularly 80% or more, as in the case of a polished or cut product obtained by the above-mentioned conventional method. It was not easy to achieve 90%.

By increasing the opening ratio of the surface cells of the sponge layer in the urethane sponge roll, in other words, removing the skin layer existing portion which is a thin film portion around the surface cell opening, or removing the surface cells of the sponge layer. By reducing the proportion of the skeleton portion present on the roll surface by thinning the skeleton or the like, the friction generated between the urethane sponge roll and the member that comes into contact with such a urethane sponge roll (the partner member) is reduced. Thereby, for example, in the case of a toner roll, the stress applied to the toner can be reduced, and the toner is effective in terms of toner transportability and supply stability, suppression of toner powdering, and the like. Since it is desirable from the viewpoint of supplying the toner uniformly, such a urethane sponge roll is used. It is, is what is requested to increase the aperture ratio of the surface cells as much as possible.

[0010]

Here, the present invention has been made in view of such circumstances, and it is an object of the present invention to provide excellent roll dimensional accuracy and surface cell aperture ratio, and furthermore, surface cell diameter. An object of the present invention is to provide a method capable of easily and industrially advantageously producing a urethane sponge roll having a sponge layer having a uniform (opening diameter).

[0011]

According to the present invention, a sponge layer made of a flexible polyurethane foam is integrally formed around a long bar-shaped core by a molding operation. Preparing a molded product in which a skin layer is formed on the surface of the sponge layer; and (b) irradiating the surface of the sponge layer of the molded product with plasma, A method for producing a urethane sponge roll, which comprises a step of melting and disappearing an existing skin layer and opening a cell immediately below the skin layer on the outer peripheral surface.

That is, in the method for producing a urethane sponge roll according to the present invention, a sponge layer made of a flexible polyurethane foam is integrally formed around a core metal by a molding operation. Therefore, even if the skin layer, which is the surface layer of the sponge layer, is removed, the roll dimensional accuracy does not deteriorate and the mold dimensional accuracy can be obtained as it is, and the skin layer on the surface of the sponge layer is melted and disappeared. By removing the cells, the cells immediately below the skin layer can be opened, and the surface layer portion is opened at a much higher opening ratio than when each cell is opened through the skin layer. Cell can be opened,
Since the cells directly under the skin layer have relatively uniform cell diameters, the uniformity of the cell openings on the outer surface of the sponge layer can be further enhanced.

Further, according to the present invention, the surface of the sponge layer of a molded article in which the sponge layer is integrally formed around the cored bar is simply irradiated with plasma. Can effectively melt / disappear (remove) only the skin layer present in the urethane sponge roll, and in addition to this, a urethane sponge roll having excellent characteristics as described above can be easily produced. For example, Japanese Unexamined Patent Publication No. 11-3874 discloses that a conventional method of obtaining a polished product (surface porous roll) by rotating and polishing a surface portion of a sponge layer at a high speed is impossible or extremely difficult.
As for the urethane sponge roll having an uneven structure formed by a plurality of ridges whose outer peripheral surface extends linearly in the roll axis direction as proposed in Japanese Patent Publication No. 9-29, a simple method called plasma irradiation is adopted. Thereby, the cell in the surface layer can be greatly opened very effectively, which is extremely advantageous in industrial productivity.

According to one preferred embodiment of such a method for producing a urethane sponge roll according to the present invention, the plasma irradiation rotates the molded article around its axis while causing the plasma to rotate in the axial direction. Advantageously, the source is moved relatively.

According to another preferred embodiment of the manufacturing method according to the present invention, the sponge layer comprises:
It is made of a flexible polyurethane foam having a density of 0.6 g / cm ³ or less, whereby the skin layer alone can be effectively melted.

Further, according to the advantageous method for producing a urethane sponge roll according to the present invention, the cell immediately below the skin layer in the total opening area of the cell under the skin layer is heated by heating the surface of the sponge layer in the molded article described above. It can be opened so as to occupy at least 70% or more.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be more specifically described below with reference to the drawings.

First, FIG. 1 is a diagram showing a schematic configuration of an example of a full-color laser beam printer using a urethane sponge roll obtained according to the method of the present invention. In FIG. 1, reference numeral 2 denotes a photosensitive drum. A charging roll 4 for charging the surface of the photosensitive drum 2 around the photosensitive drum 2, an exposure mechanism 6 for sending image information by a laser signal to form an electrostatic latent image on the photosensitive drum 2, A developing unit 8 that develops a toner image corresponding to the electrostatic latent image formed on the surface of the photosensitive drum 2; a transfer drum 10 on which the developed toner image is transferred onto the photosensitive drum 2; A cleaning device 12 is provided for removing transfer residual images and residual toner on the surface of the photosensitive drum 2. Then, the toner image transferred from the photosensitive drum 2 onto the transfer drum 10 is supplied from a paper feeding device 14 to a paper feeding roll 1.
After being further transferred to the copy paper (transfer paper) supplied by the transfer roll 16 by the transfer roll 16, the fixing roll 1
At 8, the image is fixed on the copy paper.

More specifically, in this laser beam printer, the developing unit 8 uses a toner of four colors of cyan, yellow, magenta, and black (here, a non-magnetic one-component developer is used for full-color printing). Are separately accommodated.
0, and the four developing units 20
Each developing unit 20 comes into contact with the photosensitive drum 2 at every 1/4 rotation around the rotation axis, and has a structure in which the toners of the respective hues are arranged with a phase difference of 90 degrees around the rotation axis. (Color developer) is supplied onto the photosensitive drum 2 to develop an electrostatic latent image.

As shown in FIG. 2, each developing unit 20 in the developing section 8 accommodates a toner (non-magnetic one-component developer) 24 as a color developer in a hopper 22, and The toner supply roll 26 and the developing roll 28 provided at the lower portion are rotated in the same direction while contacting each other with a predetermined press contact amount, so that the toner 24 remaining on the developing roll 28 is removed. On the side that is separated from the contact portion with the toner supply roll 26 with the rotation while being scraped off by the toner supply roll 26, the developing roll 28
At the top, the toner 24 in the hopper 22 is supplied. Note that the thickness of the toner layer formed on the developing roll 28 is regulated by a layer forming blade 29. Then, the developing roll 2
As described above, the developing roller 8 is brought into contact with the photosensitive drum 2 by １ ／ rotation about the rotation axis of the developing unit 8 and
The electrostatic latent image on the photosensitive drum 2 is developed by the toner layer formed on the photosensitive drum 8.

Next, the toner image formed by developing the electrostatic latent image on the photosensitive drum 2 in this manner is transferred onto a transfer drum 10 which is rotated in contact with the photosensitive drum 2, and The transfer is performed under the pressure between the transfer drum 10 and the transfer roll 16 on the copy paper (transfer paper) supplied from the paper supply device 14 by the paper feed roll 15 in accordance with the rotation of the transfer drum 10, and then the transfer is performed. The image is fixed on the copy paper by the heating and pressurizing action of the fixing roll 18.

By the way, the present invention relates to a toner supply roll 26 and a developing roll 2 in a printer having such a configuration.
8, charging roll 4, paper feed roll 15, transfer roll 16,
Further, the present invention is directed to a urethane sponge roll used as a cleaning roll or the like in the cleaning device 12, and such a roll is manufactured as follows.

Specifically, first, as the foaming mold, for example, as shown in FIG. 3, a mold 30 having a mold structure exhibiting a pipe shape, a so-called pipe mold, is suitably used.
By a normal molding operation, a long bar-shaped core metal 36 is formed.
A sponge layer made of a flexible polyurethane foam is integrally formed around the surface of the sponge layer, and a molded article (rough roll body) having a skin layer formed on the surface of the sponge layer is foamed and prepared. Become.

That is, in FIG. 3, a molding die 30 has a pipe 32 having a length substantially equal to the axial length of the sponge layer in the final shape of the target urethane sponge roll, and two ends of the pipe 32. Caps 34, 34 attached to each other to close the respective ends. When a predetermined metal core 36 is positioned in the pipe 32, both ends of the pipe 32 are
4 and 34 and the caps 34 and 3
At 4, the molding cavity 38 which gives the outer shape substantially similar to the final roll shape (outer shape) of the target urethane sponge roll by supporting the core metal 36 is formed in the pipe 32. . In addition, the inner surface of the pipe 32 of the molding die 30 is made smooth according to the shape of the outer peripheral surface of the target urethane sponge roll, or as disclosed in JP-A-11-38749. In order to form a urethane sponge roll having a concavo-convex surface structure by a plurality of ridges in which the outer peripheral surface of the roll extends linearly in the roll axis direction, a groove corresponding to the ridge is formed on the inner surface of a mold for molding the roll surface. It is, of course, formed.

Then, a polyurethane foam raw material for providing a sponge layer made of a desired flexible polyurethane foam is guided into a molding cavity 38 of such a molding die 30, and is subjected to a usual integral foam molding operation.
By performing the molding, as shown in FIG. 4, a sponge layer 42 made of a flexible polyurethane foam is integrally formed around the cored bar 36, and a skin layer is formed on the surface of the sponge layer 42. 44 is also formed at the same time, and the desired molded product (rough roll)
40 are obtained. Further, in the formed sponge layer 42, the cells 46 immediately below the skin layer 44 are formed.
Have a relatively uniform cell diameter.

The polyurethane foam raw material guided into the molding cavity 38 and reacted and foamed is a liquid material similar to the conventional one, and is a conventionally known reactive raw material which foams and hardens in a mold. Any of (a blend of a polyol component and a polyisocyanate component) is appropriately selected and used without any particular limitation. For example, as the polyol component constituting such a liquid polyurethane foam raw material, generally, any of known polyols such as polyether polyol, polyester polyol, and polyolefin polyol used in the production of flexible polyurethane foam is used. As the polyisocyanate component, all known polyisocyanates having at least bifunctionality or more can be used. For example, 2,4- and 2,6-tolylene diisocyanate (TDI), orthotoluidine diisocyanate (TODI) , Naphthylene diisocyanate (ND
I), xylylene diisocyanate (XDI), 4,4
'-Diphenylmethane diisocyanate (MDI) and carbodiimide-modified MDI, polymethylene polyphenyl isocyanate, polymeric polyisocyanate, and the like can be used alone or in combination.

However, in the present invention, as described later, since the skin layer 44 formed on the surface of the sponge layer 42 needs to be eliminated or removed, the flexible polyurethane foam providing the sponge layer 42 is not used. It is desirable that the heat melting property is good. For this reason, specifically, the degree of crosslinking of the polyurethane is low, for example, as a polyol component or a polyisocyanate component, their functional groups are bifunctional, and the isocyanate index is 100 or less will be suitably selected,
Generally, in the case of a flexible polyurethane foam, the skin layer 44 can be eliminated or removed by appropriately selecting various conditions described below, such as the distance from the plasma discharge port to the roll surface.

Further, the polyurethane foam raw material obtained by blending the polyol component and the polyisocyanate component may further contain a crosslinking agent, a foaming agent (water,
Low-boiling substances, gaseous substances, etc.), foam stabilizers, surfactants, catalysts, etc. are appropriately added so as to have a well-known composition which is easy to produce a sponge structure of a sponge layer after foaming. It is a reactive foaming raw material, and such a raw material may contain, if necessary, a flame retardant or a filler, and further a conductivity imparting agent or an antistatic agent for imparting a desired conductivity. Etc. can be added in the same manner as in the prior art.

In particular, in the foam structure of the sponge layer 42 of the molded article (coarse roll body) 40 formed by such a foam molding operation, the size of the cell 46 is the purpose of the urethane sponge roll. An appropriate size is selected depending on the application. Such a cell size is controlled by various known methods, for example, injection of a polyurethane foam raw material into the molding cavity 38 of the molding die 30. In addition to being controlled by the amount, it is controlled by the compounding amount of the foaming agent and the foam stabilizer.
Specifically, for example, in the case where water is used as a foaming agent, if the amount of the compound is small, the generated cells are fine, and therefore, the compound is generally compounded in a range of 0.5 to 5 phr, In the case of a foam stabilizer,
It is blended in a ratio of 0.1 to 3 phr, and the amount of raw material injected is generally 0.05 to 0.5 g.
/ Cm ³ .

In general, the sponge layer 42 formed by the foam molding operation desirably has a Asker C hardness of 70 degrees or less, and a higher hardness than that of the skin layer 44 described later. There is a problem in that the melting / disappearing (removing) operation becomes difficult, and for example, it becomes difficult to melt the skin layer 44. Furthermore, the density of such a sponge layer 42 is preferably as small as possible, and particularly, the density is 0.6 g / cm ^3.
It is desirable that such a sponge layer 42 is constituted by the following flexible polyurethane foam,
When the density exceeds 0.6 g / cm ³ ,
It is difficult to melt only the skin layer 44 neatly,
Since it is not preferable, the kind of the raw material component and the foaming conditions are appropriately selected so as to provide the sponge layer 42 having such characteristics.

The material of the molding die 30 used in the molding operation by foam molding using the polyurethane foam raw material as described above is such that at least the inner surface of the molding die 30 is made of such a polyurethane foam raw material, The polyurethane mold (sponge layer 42) generated by the foam molding operation described above is made of a material (for example, a polyolefin material such as a fluororesin material, a silicone resin material, polypropylene, and polyethylene) to which the molding die 30 is difficult to adhere. It is desirable to apply an appropriate release agent, for example, a silicone-based or fluorine-based release agent, to the inner surface of the cavity (the inner surface of the pipe 32) and to perform a foam molding operation. Mold 30 of roll body 40, especially pipe 3
2 The removal from the inner surface can be performed effectively. In the same sense, it is preferable that the inner surface of the molding die 30 (pipe 32) is slightly roughened, but it is easy to take out the molded product 40 from the molding die 30. As long as it is a mirror surface, there is no problem. However, if the degree of the surface roughening is large and the surface roughness (Rz) exceeds 50 μm, a new problem such as a marked increase in the unevenness of the molding surface is newly caused. Normal surface roughening such as shot blasting is performed so as to be not more than (Rz).

Then, by a molding operation by foam molding using such a molding die 30, a predetermined molded product (rough roll body) 40 as shown in FIG. A sponge layer 42 made of a flexible polyurethane foam is integrally formed, and a skin layer 44 has
A molded article formed simultaneously with a predetermined thickness of about 0 μm is molded. In such a molded article 40, the skin layer 44 on the surface of the sponge layer 42 has a plasma layer as described later. Since it can be melted / dissipated (removed) by irradiation, it is not necessary to form a complete film without a hole for opening the cell 46 located immediately below to the outside. Even if there is a portion or the like, it does not matter at all, rather, if there are many such pinholes and cell openings, and the skin layer 44 portion on the surface of the sponge layer 42 decreases, the more The melting / dissipating operation is facilitated, whereby the total ratio of the cell openings on the skin layer surface, in other words, the cell opening ratio, is further increased. Rukoto can be.

The molded article 40 thus obtained is further subjected to a melting / disappearing (removing) operation of the skin layer 44 on the surface of the sponge layer 42 according to the present invention. The cell 46 located immediately below the skin layer 44 is opened on the outer peripheral surface. In this case, the operation of melting and disappearing the skin layer 44 is to apply plasma to the surface of the sponge layer 42. The method of irradiating is adopted, and in particular, in the present invention, by rotating such a molded product 40 around its axis and relatively moving the plasma generation source in its axial direction. Thus, a method of melting only the skin layer 44 and eliminating it is advantageously employed. Of course, in the present invention, such a sponge layer 42 is used.
Any other method can be adopted as long as the plasma can be effectively irradiated to the surface skin layer 44. For example, the molded product is sealed in a closed container with a predetermined gas. By irradiating the molded product with plasma from a plasma discharge port having a length substantially equal to the roll length, the skin layer of the molded product can be melted and eliminated.

Here, in the melting / disappearing operation of the skin layer 44 by the above-described plasma irradiation, as a method of irradiating the plasma, the plasma molded source is relatively rotated in the axial direction while rotating the molded article around its axis. In the case where the moving method is adopted, for example, as shown in FIG. 5, the molded product 40 is rotated around its core (axis) 36, while plasma is generated in the axial direction of the molded product 40. By irradiating the surface of the sponge layer 42 of the molded article 40 with plasma while moving the source 50, the skin layer 44 on the surface of the sponge layer 42 is heated, melted, and eliminated to thereby remove the skin layer. That is, a cell 46 located immediately below 44 is opened to the outer peripheral surface.

In the present invention, the molded article 4
Regarding the plasma-excited atoms / molecules irradiated to the surface of the sponge layer 42 of 0, the kind is not limited, but conditions for irradiating the plasma such that only the skin layer 44 can be heated and melted, for example, Plasma density, which is a measure of plasma intensity, the distance from the plasma discharge port to the surface of the sponge layer 42, the rotational speed of the molded product 40 in the direction around the axis, and the relative speed of the plasma source to the molded product 40 Is appropriately selected.

For example, when the plasma density is about 10 ⁸ / cm ^{3, the} temperature of the plasma discharge port in the plasma generating source is 200 ° C., and the work surface temperature (the surface temperature of the object to be subjected to the plasma treatment) is 60 to 80. In the case where a plasma irradiating device at about ° C. is used, the distance from the plasma discharge port to the surface of the sponge layer 42 is 30 to 50.
mm. If the distance is less than 30 mm, the cell 46 located immediately below the skin layer 44 on the surface of the sponge layer 42 is instantaneously opened after the plasma irradiation, so that it becomes difficult to adjust the cell aperture ratio. On the other hand, if it exceeds 50 mm, the effect of opening the cell 46 located immediately below the skin layer is reduced even if plasma is applied. Also, the rotation speed of the molded product 40 is appropriately set according to the surface properties of the molded product 40, the output of the plasma generation source, and the like. From the viewpoint of removal and the like, low-speed rotation of generally about 10 to 20 rpm is employed. Further, in the case where the same plasma generator as described above is used, the relative speed (movement speed in the roll axis direction) of the plasma generation source 50 to the molded article 40 is preferably 10 to 150 mm / min. If the speed is less than 10 mm / min, it takes a long time for the plasma irradiation treatment. On the other hand, if the speed exceeds 150 mm / min, the skin layer 44 on the surface of the sponge layer 42 is exposed to the cell immediately below the skin layer by the plasma irradiation. This is because a portion where the portion 46 is opened and a portion where the portion 46 is not opened are mixed, that is, so-called opening unevenness occurs.

Then, by the operation of melting and disappearing (removing) the skin layer 44 by the plasma irradiation as described above, the skin layer 44 constituting the surface of the sponge layer 42 of the molded article 40 is removed. A cell 46 located immediately below such a skin layer 44 is opened, and thus, as shown in FIG. 6, a conventional structure in which the cell 46 is opened on the entire outer peripheral surface of the sponge layer 42 is used. The urethane sponge roll 60 having an extremely high cell opening ratio equivalent to a polished product or the like is formed. In addition, in such a urethane sponge roll 60, dimensional accuracy can be secured as a whole by the molding die 30, and even if the skin layer 44 is removed, a product with small dimensional variations can be obtained. In addition, by removing only the portion of the skin layer 44 (generally having a thickness of about 1 to 100 μm), the cell of the inner first layer composed of the relatively uniform cell 46 located directly under such a skin layer 44 is removed. Since the opening is made, the cell opening state on the roll surface becomes more uniform than that of a conventional polished product or the like, so that a urethane sponge roll with improved characteristics of the sponge layer 42 can be obtained.

The opening diameter of the surface cells in the urethane sponge roll 60 obtained in this manner is appropriately determined according to the intended use. The thickness is adjusted to 200 μm or less for a roll or a charging roll, and to 300 μm or less for a transfer roll. Also, the degree of softness of the sponge layer 42 is appropriately determined according to the application. For example, in the case of the toner supply roll in the hardness display, according to the measurement method shown in FIG. 5 of JP-A-9-274373. Surface length direction 50mm
Under a load of 1 mm, the hardness is set to be 350 g or less. In the case of a developing roll or a charging roll, the Asker C hardness is preferably 20 to 70 degrees. , At Asker C hardness,
An angle of 40 to 70 degrees is preferably used.

[0039]

EXAMPLES Examples of the present invention will be described below to clarify the present invention more specifically. However, the present invention is not limited by the description of such examples. Not that, of course. Also,
In the present invention, various changes, modifications, improvements, etc., based on the knowledge of those skilled in the art, in addition to the following embodiments, in addition to the above-described specific description, without departing from the spirit of the present invention. It should be understood that

First, as a molding die, a pipe type as shown in FIG. 3 having a smooth inner surface of the molding die is shown in FIG. 7 of Japanese Patent Application Laid-Open No. 11-38749. The inner surface of the mold was subjected to broaching to form a concave groove, respectively. Then, shot blasting is performed on the inner surface of the metal pipe corresponding to the inner surface of each mold, and the surface thereof is roughened so that the surface roughness: Rz becomes 10 μm, and then the silicone-based mold is released. A coating (solution having a modified silicone resin as a main component and a resin solid content of 3 to 5%) is applied and further cured by heating to form a cured layer (thickness: 5 μm) of the silicone release agent.
Was formed on the inner surface of the mold. In addition, the size of the concave groove in the mold in which the concave streak is formed on its inner surface is 50: width.
0 μm, concave pitch: 1300 μm, depth: 300 μm. In any of the pipe types, the inner diameter of the metal pipe is 16 mmφ, and the axial length thereof is 250 mm. And these pipe types are 50
° C, while having an outer diameter of 5
A core of mmφ was set.

On the other hand, 90 parts by weight of EP-828 (polyether polyol manufactured by Mitsui Chemicals, Inc., OH value = 28)
POP-31-28 (Polymer polyol manufactured by Mitsui Chemicals, Inc., OH value = 28) 10 parts by weight, diethanolamine 2 parts by weight, 31 (Tertiary amine catalyst manufactured by Kao Corporation) 0.5 part by weight, Toyocat HX-3
5 (Tertiary amine catalyst manufactured by Tosoh Corporation) 0.1 part by weight,
0.1 parts by weight of dibutyltin dilaurate (tin-based catalyst),
2. 2 parts by weight of water (foaming agent), 3 parts by weight of L-5309 (silicone-based foam stabilizer manufactured by Nippon Unicar Co., Ltd.), and Sumidur VT-80 (isocyanate manufactured by Sumitomo Bayer Urethane Co., NCO% = 45) By blending 5 parts by weight, the intended polyurethane foam raw material was prepared.

Next, using a polyurethane foam raw material having the above composition, 5 g of the polyurethane foam raw material was put into each of the above-mentioned pipe molds, and kept in an oven at 50 ° C. for 30 minutes to foam and harden. Later, from the pipe type,
The foam molded article was taken out.

By such a process, three sponge-molded products having a smooth sponge layer (Examples 1 to 3 of the present invention) and a plurality of ridges extending linearly in the roll axis direction on the outer peripheral surface of the sponge layer are formed. (Example 4 of the present invention), and a microphotograph of the surface of the sponge layer of each of the molded products before the plasma irradiation was performed. The ratio of the opening per unit area on the surface of the sponge layer (surface cell opening ratio) before the irradiation of the surface of the sponge layer was calculated. The average value (average opening diameter) of the cell opening diameters on the layer surface was calculated, and the surface cell opening ratio and the average opening diameter are shown in Table 1 below.

Further, while rotating each of the thus obtained molded articles around their axes at 20 rpm, a plasma irradiation apparatus (trade name “PLASMA JET”, manufactured by Kasuga Electric Co., Ltd., model: PJ-1; consumption: As shown in FIG. 5, the plasma discharge port of the plasma irradiating apparatus is connected to the surface of the sponge layer of the molded product by using 0.5 kW of power, a discharge port temperature of 200 ° C., and a work surface temperature of 60 to 80 ° C. While being slid, the molded article was irradiated with plasma. The distance from the plasma discharge port to the surface of the sponge layer and the slide speed of the plasma discharge port with respect to the molded product when the plasma was irradiated are shown in Table 1 below.

After irradiating the entire surface of the sponge layer of the molded product with plasma, a micrograph of the surface of the sponge layer of each molded product was taken in the same manner as before the plasma irradiation, and based on the photograph, The surface cell aperture ratios in the inventive examples 1 to 4 after the plasma irradiation and the average aperture diameters in the inventive examples 3 and 4 were calculated, and the results are also shown in Table 1 below.

The micrographs of the sponge layer surface of the molded article before the plasma irradiation and the micrographs of the sponge layer surface after the plasma irradiation obtained for Examples 3 and 4 of the present invention are shown in FIG. 7 and FIG.

[0047]

[Table 1]

As is clear from the results in Table 1, in a urethane sponge roll having a smooth outer peripheral surface as in Examples 1 to 3 of the present invention, the surface of the sponge layer is irradiated with plasma to directly under the skin layer. In particular, by appropriately selecting conditions such as the distance from the plasma discharge port to the surface of the sponge layer, the surface cell aperture ratio of Example 3 of the present invention was appropriately selected. Of 82.3%, which is approximately equal to that of a polished or cut product, and the photograph in FIG. 7 shows that the openings of the surface cells are also highly uniform. Admitted. Further, as is clear from Table 1 and FIG. 8, as in Example 4 of the present invention, the outer peripheral surface of the roll has an uneven surface structure by a plurality of ridges provided so as to extend linearly in the roll axis direction. In the urethane sponge roll described above, it is recognized that the opening of the surface cell can be significantly improved by irradiating plasma.

[0049]

As is apparent from the above description, according to the present invention, a urethane sponge roll having an extremely high surface cell opening ratio and excellent roll dimensional accuracy can be advantageously provided. A urethane sponge roll having a porous surface with a uniform surface cell diameter, which was difficult to realize with a polished product or a cut product, can be provided. Even if there is, it is possible to easily open the cell of the surface layer part, and in addition, the urethane sponge roll having such characteristics can be manufactured in a simple process at a low cost. It can be done.

The uniform opening of the surface cells makes it possible to use the urethane sponge roll obtained according to the present invention as a toner supply roll, so that unevenness in toner supply and scraping is less likely to occur.
In addition, by using the developing roll, the toner carrying property is good and uniform, and there is a characteristic that image unevenness hardly occurs. Further, the charging roll exhibits uniform charging characteristics. Characteristics, such as the difficulty of appearing.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view clarifying a mechanism of a full-color laser printer using a urethane sponge roll according to the present invention.

FIG. 2 is an explanatory sectional view showing one of the developing units in FIG. 1 in an enlarged manner.

FIG. 3 is an explanatory longitudinal sectional view showing an example of a mold used in the method for producing a urethane sponge roll according to the present invention.

FIG. 4 is an explanatory view showing a molded product obtained by using the mold shown in FIG. 3;

FIG. 5 is an explanatory view showing an example of a method for removing a skin layer by irradiating a molded article with plasma according to the present invention.

FIG. 6 is an explanatory view showing an example of a urethane sponge roll obtained according to the present invention.

FIG. 7 is a micrograph showing the surface of a sponge layer before and after plasma irradiation of a molded product having a smooth roll outer peripheral surface obtained in an example.

FIG. 8 is photomicrographs showing the surface of the sponge layer before and after plasma irradiation, respectively, of the molded product obtained in the example and having an uneven roll outer peripheral surface.

[Explanation of symbols]

2 Photoreceptor drum 4 Charging roll 6 Exposure mechanism 8 Developing unit 10 Transfer drum 12 Cleaning device 14 Feeder 15 Feeder roll 16 Transfer roll 18 Fixing roll 20 Developing unit 22 Hopper 24 Toner 26 Toner supply roll 28 Developing roll 29 Layer Forming blade 30 Mold 32 Pipe 34 Cap 36 Core metal 38 Mold cavity 40 Mold molding 42 Sponge layer 44 Skin layer 46 Cell 50 Plasma source 60 Urethane sponge roll

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G03G 15/02 101 G03G 15/02 101 4F073 15/08 501 15/08 501A 4F209 501D 15/16 103 15/16 103 21 / 10 B29K 75:00 // B29K 75:00 105: 04 105: 04 B29L 31:32 B29L 31:32 C08L 75:04 C08L 75:04 G03G 21/00 312 F term (reference) 2H003 BB11 CC05 2H032 AA05 BA19 BA23 2H034 BC01 BC02 BC03 2H077 AC04 AD06 FA13 FA22 3J103 AA02 AA13 AA32 BA41 EA02 EA20 HA03 HA12 HA18 HA48 HA54 4F073 AA21 BA28 BB04 BB05 CA01 CA04 CA09 4F209 AA31 AD03 AD18 AG03 AG20 AG28 AH03 PA05 P05B05

Claims (4)

[Claims] 1. A molded product in which a sponge layer made of a flexible polyurethane foam is integrally formed around a long bar-shaped core by a molding operation, and a skin layer is formed on the surface of the sponge layer. Irradiating plasma to the surface of the sponge layer of the molded article, melting and disappearing the skin layer present on the surface of the sponge layer, and opening the cell immediately below the skin layer to the outer peripheral surface. A method for producing a urethane sponge roll, comprising: 2. The urethane sponge according to claim 1, wherein the plasma irradiation is performed by relatively moving a plasma generation source in the axial direction while rotating the molded article around its axis. Roll manufacturing method. 3. The method for producing a urethane sponge roll according to claim 1, wherein the sponge layer is made of a flexible polyurethane foam having a density of 0.6 g / cm ³ or less. 4. The method for producing a urethane sponge roll according to claim 1, wherein the total opening area of the cells occupies at least 70% or more of the outer peripheral surface of the roll.