JP2002304052A - Method for producing toner feed roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a toner feed roller by which open area ratio, opening diameter and the communicating state of cells can be effectively increased and a roller having low hardness and good flexibility can be reliably obtained. SOLUTION: In the method for producing a toner feed roller, when the outermost layer comprising polyurethane foam is formed using a urethane foam forming composition containing polyol components and isocyanate components as a foamable material, a high PO polyol containing >=70% polypropylene oxide and a high EO polyol containing >=50% polyethylene oxide are used as the polyol components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a toner supply roller for supplying toner to a developing roller in a developing mechanism of an electrophotographic apparatus such as a copying machine or a printer or an electrostatic recording apparatus. The present invention relates to a method of manufacturing a toner supply roller that can reliably obtain a toner supply roller having low hardness, high aperture ratio, and excellent air permeability.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus such as a copying machine or a printer or an electrostatic recording apparatus, first, the surface of a photoconductor (image forming body) is firstly charged with a charging roller or the like. Charged uniformly by the charging means, form an electrostatic latent image by projecting an image from the optical system on this photoreceptor and eliminating the charging of the portion hit by the light,
A toner is supplied from a developing roller to the electrostatic latent image to form a toner image by electrostatic adhesion of the toner, and the toner image is transferred to a recording medium such as paper by a transfer unit such as a transfer roller, and further transferred. Is heated and fixed on a recording medium by a fixing means such as a fixing roller to obtain a printed image.

For example, as shown in FIG. 2, a developing roller 2 is placed in contact with or close to a photosensitive drum (latent image holding member) 3 and a toner supply roller 1 is further attached to the developing roller 2. By rotating the photosensitive drum 3, the developing roller 2, and the toner applying roller 1 in the direction of the arrow in the drawing, the toner supply roller 1 removes toner from the toner pool in the toner cassette. t is supplied to the surface of the developing roller 2, and the toner t is formed into a uniform thin layer by the layering blade 4. In this state, the developing roller 2 is rotated while being in contact with or close to the photosensitive drum 3. Is developed from the developing roller 2 and adheres to the latent image on the photosensitive drum 3 to visualize the latent image. Here, in the drawing, reference numeral 5 denotes a transfer unit, which transfers a toner image onto a recording medium 6 such as paper. Reference numeral 7 denotes a cleaning unit. The toner remaining on the surface is removed. In FIG. 2, a charging unit such as a charging roller is omitted.

Here, in such a developing system,
The toner supply performance of the toner supply roller 1 greatly affects the obtained image, and in order to surely obtain a good image, the toner conveyance performance (toner supply performance) of the toner supply roller 1 is changed to the developing roller 2 or the photosensitive drum. Very important together with the performance of 3.

In this case, the toner supply roller 1 usually has a structure in which an elastic layer made of a foamed material such as a soft polyurethane foam is formed on the outer periphery of a shaft. It is greatly affected by the cell formation state of the foam constituting the elastic layer.

That is, the elastic layer of the toner supply roller 1 is formed by, for example, injecting a foamable polyurethane raw material mixture into a mold in which a shaft is disposed and stirring and foaming the mixture. In this case, the toner supply roller 1
As shown in FIG. 1 (A), a plurality of independent cells 9 communicate with each other through appropriate small holes 10 while maintaining the independence, as shown in FIG. , And the cell on the surface is small hole 1
1, it is preferable that the roller surface is opened on the roller surface.

However, the foam cells of the polyurethane foam take various different forms depending on the raw material composition, molding conditions, foaming conditions and the like. For example, as shown in FIG. 1C, the cells 9 are not connected to each other, and the cells 9 are not communicated with each other to form independent closed spaces, and there is no opening to the roller surface, as shown in FIG. It may be. In this case, in the state shown in FIGS. 1B and 1C, good elasticity cannot be obtained, the toner holding force is reduced, or the holding force becomes uneven, resulting in good toner transportability. In some cases, the toner may not be obtained, or the toner may be clogged during long-term use, and a sufficient conveyance amount may not be obtained.

As shown in FIG. 1 (A), when a roller in which foam cells 9 are opened to the surface through small holes 11 is obtained, a desired opening ratio can be obtained by cutting the surface after forming the roller. However, it has also been proposed to obtain a foam having the above openings directly at the time of molding a flexible polyurethane foam. According to this method, it is possible to manufacture a toner supply roller very efficiently.

Conventionally, as a method of obtaining the roller having a sufficient surface opening by forming the communication holes 10 and 11 at the time of molding in a cylindrical mold without performing surface cutting after molding, a special inner hole is used. A method of improving the opening ratio of a surface skin usually formed using a cylindrical mold having a surface state to 20% or more (Japanese Patent Application Laid-Open No. 9-274373), selecting a release agent, and removing the inner surface of the cylindrical mold. There are known a method of forming an opening in the surface skin by appropriately roughening, and a method of blending a polymer polyol in a raw material mixture and using the mixture to improve the communication of cells and improve the opening ratio.

Here, it is preferable that the foam constituting the surface of the toner supply roller has a high opening ratio, fine cells, sufficient communication, and low hardness. However, it is not always possible to obtain a toner supply roller having sufficient performance.

That is, in order to sufficiently improve the surface aperture ratio, there is a limit to the method of improving the aperture ratio by adjusting the inner surface state of the cylindrical mold as described above, and the aperture ratio is not necessarily sufficiently increased. May not be improved.
In addition, in the method based on the blending of the polymer polyol as described above, if the opening ratio and the opening diameter are sufficiently improved, the whole cell becomes rough or the hardness becomes high, which is unsuitable as a toner supply roller. In some cases.

The present invention has been made in view of the above circumstances, and forms a communication hole and an opening of a cell at the time of molding with a cylindrical mold, thereby forming a foam layer on the surface without performing cutting after molding. In the case of obtaining a toner supply roller, a toner supply that can effectively improve the aperture ratio, the opening diameter, and the communication state of the cells, and can reliably obtain a roller having low hardness and good flexibility. An object of the present invention is to provide a method for manufacturing a roller.

[0013]

Means for Solving the Problems and Embodiments of the Invention The present inventor has conducted intensive studies in order to achieve the above object, and as a result, obtained a roller base having a shaft or an appropriate intermediate layer formed on the outer periphery of the shaft. Placed in a cylindrical mold, inject foaming material into the mold to form an outermost layer of foam on the outer periphery of the shaft or intermediate layer, at least the outer peripheral surface of which was formed of foam When a roller is obtained, a high P フ ォ ー ム polyol containing at least 70% of a polypropylene oxide component and a high EО polyol containing at least 50% of a polyethylene oxide are used in combination, and a urethane foam containing these polyol components and an isoanate component is used. By forming the outermost layer made of a polyurethane foam using the composition as the foaming material, the aperture ratio and the aperture diameter can be effectively improved. The present invention has been found that it is possible to achieve a good internal cell communication state as well as to achieve good reduction in hardness and improvement in flexibility.

Therefore, according to the present invention, a shaft or a roller base having an appropriate intermediate layer formed on the outer periphery of the shaft is arranged in a cylindrical mold, and a foaming material is injected into the mold to form the shaft or the intermediate. A method for producing a toner supply roller in which an outermost layer made of a foam is formed on the outer periphery of a layer to obtain a roller having at least an outer peripheral surface formed of a foam, wherein the urethane contains a polyol component and an isoanate component as the foaming material. An outermost layer made of a polyurethane foam is formed using the foam expandable composition, and at this time, as the polyol component, a high PО polyol containing 70% or more of a polypropylene oxide component and a high PО polyol containing 50% or more of a polyethylene oxide. Provided is a method for producing a toner supply roller characterized by using a combination of E @ polyol. Things.

Hereinafter, the present invention will be described in more detail. As described above, the method for manufacturing the toner supply roller of the present invention uses a high PО polyol and polyethylene oxide containing 70% or more of a polypropylene oxide component.
% Of the roller outermost layer by injecting a urethane foam expandable composition containing the polyol component and the isoanate component into a cylindrical mold as a foaming material and foaming the mixture. This forms the constituent polyurethane foam.

That is, the method for producing a toner supply roller of the present invention comprises a polyol obtained by adding polypropylene oxide and polyethylene oxide to an appropriate starting material;
When the outermost layer of the roller is formed of a polyurethane foam by mixing with an isocyanate compound and curing by heating, the high PO polyol and the high EO polyol are used in combination as the polyol component.

In this case, the high PO polyol and high E
As the starting material of the O polyol, those having two or more active hydrogens are usually used, and specifically, glycerin, trimethylolpropane, triethanolamine,
Hexanetriol, pentaerythritol, propylene glycol, ethylene glycol and the like are exemplified.

In the present invention, a polyol obtained by adding polyethylene oxide or polypropylene oxide to these starting materials is used as the above-mentioned high PO polyol and high EO polyol. In this case, the high PO polyol has a polypropylene oxide content of 70% or more. That is, the ethylene oxide / propylene oxide ratio (EO / PO) is 30/70 to 0/100, and preferably EO / PO = 20/80 to 0/100. The high EO polyol contains at least 50% of polyethylene oxide, that is, EO /
PO = 50 / 50-100 / 0, preferably EO / PO = 75 / 25-100 / 0, more preferably EO / PO = 80 / 20-100 / 0, further preferably EO / PO = 90/10 to 100/0.

In the present invention, the high PO polyol and the high E
O polyol is used in combination, but in this case, high P
The use ratio of the O polyol and the high EO polyol is not particularly limited, but is usually high PO polyol / high EO polyol = 97/3 to 50/50, particularly 95/5 to 70/20 by weight. It is preferable that In this case, if the use ratio of the high EO polyol is too small,
In some cases, it is not possible to obtain the desired surface aperture ratio and aperture diameter, while if the usage ratio of the high EO polyol is too large,
Changes in physical properties and dimensions due to humidity may increase.

Next, as the isocyanate component to be reacted with the polyol component, a general polyisocyanate used in the production of a flexible polyurethane foam can be used. Specifically, tolylene diisocyanate (ТDI) crude TDI, 4,4-diphenylmethane diisocyanate (MDI), crude MDI, having 2 to 18 carbon atoms
Alicyclic polyisocyanates, and mixtures and modified products of these polyisocyanates, such as prepolymers obtained by partially reacting with polyols.

According to the production method of the present invention, an outer layer is formed when a polyurethane foam is formed by using the urethane foam expandable composition containing the above-mentioned high PO polyol, high EO polyol and polyisocyanate. In addition to the above-mentioned polyol component and polyisocyanate component, components commonly used for foaming raw materials for polyurethane foams, specifically, a foam stabilizer, a crosslinking reaction catalyst, and the like can be added to the foaming composition as needed.

In the production method of the present invention, a roller base is placed in a cylindrical mold, and the polyurethane foam expandable composition is poured into the mold to form an outermost layer of polyurethane foam around the roller base. In this case, as the roller base, a shaft made of metal or the like, or a member provided with an intermediate layer made of another foam or an elastomer on the outer periphery of the shaft can be used. Usually, it is preferable that only the shaft is used as the substrate, and the outermost layer made of the polyurethane foam using the polyurethane foam expandable composition is formed directly on the outer periphery of the shaft.

According to the method of manufacturing a toner supply roller of the present invention, a toner supply roller having a high aperture ratio, a fine cell, sufficient communication, and a low hardness can be reliably obtained. is there. In this case, the opening ratio can be evaluated based on the surface opening diameter, and the communication state of the cells can be evaluated based on the air permeability.
00-500 μm, especially 150-400 μm, hardness 0.
A roller having a pressure of 2 to 0.7 N / cm, particularly 0.3 to 0.5 N / cm, and air permeability of 2 to 20 kPa, particularly 2 to 10 kPa can be obtained.

The above-mentioned air permeability is a value measured by the apparatus shown in FIG. That is, the compressed air supply pipe 12 is connected to the outlet of the vacuum pump c, a nozzle of 1 to 10 mm is attached to the end of the pipe 12, and the end of the pipe 12 is pressed against the outer peripheral surface of the toner supply roller 1, This is an internal pressure measured by a pressure gauge e connected to an intermediate portion of the compressed air supply pipe 12 when the compressed air is pressure-fed from the vacuum pump c to the roller 1 at a pressure of 10 to 70 kPa. The hardness is
"AUTOGRAPH" compression tester manufactured by Shimadzu Corporation
This is a value obtained by measuring the stress at a press-in amount of 1 mm using "AGS-500A" and dividing the measured value by the axial pressure contact length of the roller.

[0025]

The present invention will be more specifically described below with reference to examples and comparative examples. A metal shaft is set in a cylindrical mold (16φ) whose inner peripheral surface is coated with a fluororesin, and the urethane foam foamable composition having the composition shown in Table 1 below is thoroughly stirred in the mold. Then, an elastic layer made of a flexible polyurethane foam was formed on the outer periphery of the shaft to obtain a toner supply roller. The mixing ratios in Table 1 are all parts by weight.

[0026]

[Table 1] FT703: Sanyo Kasei Co., Ltd., polyol, EO / P
O = 13/87 (OH value: 33) FT103: manufactured by Sanyo Chemical Co., Ltd., polyol, EO / PO = 75/25 (OH value: 33) P0P31-28: Mitsui Chemicals, Inc.
Polyol (OH value: 28) SRX274C: Toray Dow Corning Silicone Co., Ltd., foam stabilizer Kaorizer 31: Kao Corporation, tertiary amine catalyst Kaorizer NO1: Kao Corporation, fat Aromatic tertiary amine catalyst T80: Tolylene diisocyanate (NCO%: 48) manufactured by Mitsui Chemicals, Inc.

The hardness, surface opening diameter and air permeability of each of the obtained toner supply rollers were examined. Table 2 shows the results. In this case, the above-mentioned air permeability was measured at four locations uniformly set on the outer peripheral surface of the roller at a pressure of 50 kPa by using the apparatus shown in FIG. In addition, the above hardness is measured by a compression tester “AUTOGRAPH AGS-500A” manufactured by Shimadzu Corporation.
By the above-mentioned measurement method using

[0028]

[Table 2]

As shown in Table 2, the toner supply rollers of Examples 1 and 2 obtained by the production method of the present invention were low in hardness but excellent in air permeability.
On the other hand, in the toner supply rollers of Comparative Examples 1 and 2 obtained by the method using the polymer polyol conventionally proposed, the hardness was not sufficiently reduced and the air permeability was low. , 2 rollers were inferior.

[0030]

According to the production method of the present invention, it has a sufficient opening ratio, low hardness, good cell communication (air permeability), and excellent toner transport performance (toner supply performance). The toner supply roller can be reliably obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing an internal structure of a foam constituting a toner supply roller.

FIG. 2 is a schematic diagram illustrating an example of a developing device.

FIG. 3 is a schematic view showing an example of an apparatus for measuring the air permeability of a roller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Toner supply roller 9 Foam cell 10 Communication port 11 Opening 12 Compressed air supply pipe c Vacuum pump e Pressure gauge

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) // (C08G 18/48 C08G 101: 00 101: 00) B29K 75:00 B29K 75:00 105: 04 105 : 04 B29L 31:32 B29L 31:32 (72) Inventor Koji Achiba 1 Kashio-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture F-term in the Bridgestone Yokohama Plant Co., Ltd. FA05 GA57 GA58 HA04 HA12 HA48 4F204 AG20 AG26 AH04 EA01 EB01 EB12 EF01 4J034 BA07 DA01 DB03 DB04 DC50 DG03 DG04 HA01 HA07 HC12 HC64 JA01 NA03 QB16 QC01 QD03 RA11

Claims (5)

[Claims] A roller base having a shaft or an appropriate intermediate layer formed on the outer periphery of the shaft is placed in a cylindrical mold, and a foaming material is injected into the mold to form a roller on the outer periphery of the shaft or the intermediate layer. A method for producing a toner supply roller in which an outermost layer of a foam is formed to obtain a roller having at least an outer peripheral surface formed of a foam, wherein a urethane foam foamable composition containing a polyol component and an isoanate component as the foaming raw material An outermost layer made of a polyurethane foam is formed by using a product, and at this time, a polypropylene oxide component is used as the polyol component in an amount of 70%.
A method for producing a toner supply roller, comprising using a high-P polyol containing above and a high-E polyol containing 50% or more of polyethylene oxide in combination. 2. The use ratio of the high PО polyol and the high EО polyol is such that the weight ratio of the high PО polyol / high EО polyol is high PО polyol / high EО.
2. The method for producing a toner supply roller according to claim 1, wherein the polyol is 97/3 to 50/50. 3. The high PО polyol is a polyol having an EO / PO ratio of 20/80 to 0/100.
3. A method for manufacturing a toner supply roller according to item 2. 4. The high EО polyol is a polyol having an EO / PO ratio of 75/25 to 100/0.
4. The method for producing a toner supply roller according to any one of items 3 to 3. 5. The method for producing a toner supply roller according to claim 1, wherein an outermost layer made of a polyurethane foam having foam cells opened on the surface is formed.