JPH10312106A - Developing roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing roll with which the separation of silicone can be prevented and surface smoothness is improved by mixing a specified tin compound into a resin composition forming the outer-most layer of developing roll. SOLUTION: Concerning the developing roll for which one layer is formed on the outer peripheral surface of shaft body, the outermost layer in that layer is formed from the resin composition including the tin compound component expressed by the formula of (Cn H2n+1 )2 -Sn-(OCOCmH2n+1 )2 . In the formula, (n) and (m) express integers from 1 to 20. As such a developing roll, structure forming an inner-most layer 2 along with the outer peripheral surface of shaft body 1, forming an intermediate layer 3 on that outer peripheral surface and further forming an outer-most layer 3 on that outer peripheral surface can be presented, for example. Thus, the mutual solubility of silicone and thermosetting polyurethane resin to be used as resin compositions is improved, for example, and the separation of silicone and thermosetting polyurethane resin or the like can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing roll used in an electrophotographic copying machine, a printer and the like.

[0002]

2. Description of the Related Art Generally, copying by an electrophotographic copying machine is performed as follows. That is, a document image is formed as an electrostatic latent image on a photoreceptor rotating about an axis, and toner is adhered to the latent image to form a toner image. Next, copying is performed by transferring the toner image to copy paper. In this case, in order to form an electrostatic latent image on the surface of the photoconductor, the surface of the photoconductor is charged in advance, and a document image is projected on the charged portion through an optical system, and the image is irradiated with light. 2. Description of the Related Art An electrostatic latent image is formed by canceling the charge of a part. As a method for forming a toner image on the electrostatic latent image formed on the photoreceptor surface in this way, as shown in FIG. 3, a method using a developing roll 21 (contact developing method) is employed. That is, the toner box 2
2 is adhered to the surface of the sponge roll 24 rotating in the direction of the arrow, and the developing roll 2 which is in sliding contact with the sponge roll 24 and also in sliding contact with the photoconductor 25 is rotated.
The toner 23 is transferred to one surface. The toner 23 that has moved to the surface of the developing roll 21 moves to the electrostatic latent image portion on the surface of the photoconductor 25, and a toner image is formed on the surface of the photoconductor 25.
The toner image thus formed is transferred onto the transferred copy paper via a transfer device, and is then fixed on the copy paper by a fixing roll or the like. Copying is performed in this manner. In FIG. 3, reference numeral 26 denotes a layer forming blade.

As a developing roll used in the electrophotographic copying machine, for example, as shown in FIG. 4, an innermost layer 2 is formed along an outer peripheral surface of a cored bar 1 and an intermediate layer 3 is formed on the outer peripheral surface. Are formed, and a developing roll having a three-layer structure in which an outermost layer 14 is formed on the outer peripheral surface thereof is generally used. The outermost layer 14 is formed, for example, by applying a resin composition obtained by mixing silicone and a thermoplastic polyurethane resin or the like to form a coating on the surface of the intermediate layer 3 and then drying.

[0004]

However, when the above silicone and a thermoplastic polyurethane resin are mixed to form a coating material, the silicone is not compatible with the thermoplastic polyurethane resin or the like because of the poor compatibility between the silicone and the thermoplastic polyurethane resin. And separate. Therefore, when the resin composition in such a state is applied to the roll surface and dried, the separated silicone is solidified and solidified, so that the surface of the developing roll is roughened. Therefore, there arises a problem that the surface is inferior in smoothness and good toner transportability cannot be obtained.

The present invention has been made in view of such circumstances, and has as its object to provide a developing roll which can prevent separation of silicone and has excellent surface smoothness.

[0006]

In order to achieve the above object, a developing roll according to the present invention is a developing roll in which at least one layer is formed on the outer peripheral surface of a shaft, and the developing roller has the most The outer layer is formed of a resin composition containing the following component (A). (A) A tin compound represented by the following general formula (1).

Embedded image (C _n H _{2n + 1} ) ₂ —Sn— (OCOC _m H _{2m + 1} ) ₂ (1) [In the formula (1), n and m represent an integer of 1 to 20. ]

In the developing roll of the present invention, the outermost layer among the above-mentioned layers means the layer when the number of layers is one, and literally means the outermost layer when there are two or more layers.

[0008] That is, the present inventors have repeated studies to obtain a developing roll which can prevent separation of silicone and has excellent surface smoothness. In the course of the series of research, first, he recalled the use of a specific tin-based compound (component (A)) conventionally used as a curing accelerator such as an epoxy resin or a phenol resin or a stabilizer for a vinyl chloride resin. . The specific tin-based compound (component (A)) is added to the resin composition forming the outermost layer of the developing roll, so that, for example, silicone and thermoplastic polyurethane resin used as the resin composition can be used. Better compatibility and, as a result,
The present inventors have found that separation of silicone and thermoplastic polyurethane resin can be prevented, and have reached the present invention.

[0009]

Next, an embodiment of the present invention will be described in detail.

As the developing roll of the present invention, for example,
As shown in FIG. 1, the shaft 1 has a structure in which an innermost layer 2 is formed along the outer peripheral surface, an intermediate layer 3 is formed on the outer peripheral surface, and an outermost layer 4 is further formed on the outer peripheral surface. I can give it.

As the shaft 1, any conventionally known shaft can be used. For example, a metal core made of a solid metal body, a metal cylindrical body having a hollow inside, or the like is used. Examples of the material include aluminum and stainless steel.

The material for forming the innermost layer 2 formed on the outer peripheral surface of the shaft 1 and the intermediate layer 3 formed on the outer peripheral surface thereof are not particularly limited, and any conventionally known materials may be used. You may. For example, as a material for forming the innermost layer 2, ethylene-propylene-diene rubber (EPD)
M), styrene-butadiene rubber (SBR), silicone rubber, polyurethane elastomer, and the like, and carbon black blended. Further, the intermediate layer 3
Examples of the forming material include EPDM, SBR, nitrile rubber, hydrogenated nitrile rubber, polyurethane elastomer, polyester, N-methoxymethylated nylon, and the like, and carbon black, metal oxide, quaternary ammonium salt, borate, and the like. One containing a conductive agent is exemplified.
A conventionally known method is applied to the method of preparing the material for forming the innermost layer 2 and the intermediate layer 3. To give an example, first, the material (compound form) of the innermost layer 2 is
The above components can be prepared by kneading with a kneading machine such as a kneader. The material for forming the intermediate layer 3 (coating liquid) can be prepared by kneading the above components with a ball mill or a roll, adding a solvent to the mixture, and mixing and stirring.

The outermost layer 4 formed on the outer peripheral surface of the intermediate layer 3 is formed by using a resin composition containing a specific tin compound represented by the following general formula (1).

[0014]

Embedded image (C _n H _{2n + 1} ) ₂ —Sn— (OCOC _m H _{2m + 1} ) ₂ (1) [In the formula (1), n and m represent an integer of 1 to 20. ]

The values of n and m in the general formula (1) are particularly preferably n = 4 to 8 and m = 1 to 11.
By setting the values of n and m in such ranges, it becomes possible to effectively prevent separation of silicone and thermoplastic polyurethane resin which are generally used as a resin composition.

In the resin composition of the present invention, in addition to the specific tin compound (component A), a material generally used as an outermost layer forming material of a developing roll can be blended. Examples of such a material include a combination of silicone and a thermoplastic polyurethane resin, and a combination of silicone and various rubbers or a phenolic resin. Of these, a combination of silicone having excellent toner release properties and chargeability and a thermoplastic polyurethane resin having excellent wear properties and strength is particularly preferable.

Examples of the silicone include a condensation reaction type silicone and an addition reaction type silicone.

The molecular weight of the silicone is 200
It is preferably from 0 to 600,000, particularly preferably 100
00 to 200,000.

The thermoplastic polyurethane resin preferably comprises a combination of a hard segment and a soft segment and has a molecular weight of 5,000 or more.

The hard segments include diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPD).
Isocyanate-based substances such as I). As the soft segment, ethylene adipate (E
A), butylene adipate (BA), polycaprolactam (PCL), hexamethylene adipate (HA), polyester polyol such as hexamethylene carbonate polyester (PCP), or polypropylene glycol (PPG) or polytetramethylene glycol (PTMG) And other polyether polyols (molecular weight 5
00 to 10000). These have -O at the end.
It may have an H group, a —NCO group, and a —NH ₂ group.

The thermoplastic polyurethane resin can be produced, for example, by mixing isocyanate and polyol at a predetermined ratio, reacting in the presence of a catalyst, and taking out the mixture at a place where the viscosity is stable. In the reaction, ethylene glycol, propylene glycol, 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), trimethylolpropane (TM
P), hydroquinone diethylol ether (BHE)
A chain extender such as B) or a curing agent may be added.

The thermoplastic polyurethane resin includes:
Those having -OH groups at both ends are preferred. This is because if -NCO groups or -NH ₂ groups remain at both ends, moisture in the air or bonding between molecules occurs, so that the surface state changes or tack occurs.

When silicone and a thermoplastic polyurethane resin are used in addition to the specific tin compound (component A) as a material for forming the resin composition, the preferred amounts of these are as follows. . The compounding amount of the specific tin compound (component A) is preferably from 0.01 to 20 parts, more preferably from 1 to 10 parts, per 100 parts by weight of the silicone (hereinafter abbreviated as "part"). It is. The amount of the silicone is preferably set to 200 parts or less, particularly preferably 25 to 150 parts, based on 100 parts of the thermoplastic polyurethane resin.

The resin composition according to the present invention includes:
In addition to the specific tin-based compound (component A), silicone, thermoplastic polyurethane resin and the like, a conductive agent is blended for the purpose of imparting an appropriate volume electric resistance (10 ² to 10 ¹¹ Ω · cm). be able to. The characteristic relating to the volume electric resistance is important as the characteristic of the outermost layer 4 of the developing roll.

Examples of the conductive agent include c-TiO ₂ , c-
ZnO, carbon black, c-SnO ₂ , iron oxide, graphite, potassium titanate, quaternary ammonium salt,
Borates, lithium salts and the like can be mentioned. These may be used alone or in combination of two or more. Above all, c-TiO is preferred in that an appropriate volume electric resistance can be obtained.
It is preferable to use ₂ , c-ZnO and a quaternary ammonium salt. In addition, "c-" means having conductivity.

Furthermore, in addition to the above-mentioned conductive agent, a resin crosslinking agent, a charge controlling agent, a filler, and the like can be appropriately added to the resin composition of the present invention, if necessary.

As for the thermoplastic polyurethane resin to be crosslinked, various isocyanates (MDI, TD
I, IPDI, etc.), amino resins, cross-linking agents (MOCA, ethylene diol, butane diol, etc.). Examples of the charge control agent include quaternary ammonium salts, borates, azine-based (nigrosine-based) azo compounds, oxynaphthoic acid-based metal complexes, salicylic acid-based metal complexes, and surfactants (anionic, cationic, nonionic). System) and the like. Examples of the filler include inorganic substances such as silica, calcium carbonate, and mica.

Next, the resin composition of the present invention comprises:
Using the above materials, for example, it can be produced by the method shown below.

First, the conductive agent is dispersed in a solution of the thermoplastic polyurethane resin. As a dispersion method, the thermoplastic polyurethane resin is converted into methyl ethyl ketone (M
EK), tetrahydrofuran (THF) or the like, and then dissolving the conductive agent therein, or kneading the thermoplastic polyurethane resin and the conductive agent using a kneader such as a twin screw extruder. And a method of dissolving the obtained kneaded material in a solvent. MEK, T
In addition to HF, toluene, dimethylformamide (DM
F), dimethyl sulfoxide (DMSO), methyl isobutyl ketone (MIBK), cyclohexanone and the like can be used. These may be used alone or in combination of two or more.

Then, the silicone and the specific tin-based compound (component A) are added to the dispersion of the thermoplastic polyurethane resin and the conductive agent, and these are stirred to prepare a desired resin composition. . As the stirring method,
There is no particular limitation. For example, the spring is rotated at a speed (500 to 2000 rpm) at which the entire coating liquid can be sufficiently rotated until the reaction sufficiently proceeds (that is, until the viscosity becomes constant).
Methods such as stirring may be used.

As a material for forming the resin composition,
When silicone and various rubbers or phenolic resin are used, they can be produced by the same method as that when the above silicone and thermoplastic polyurethane resin are used.

Next, a method for producing the developing roll of the present invention using the above resin composition will be described. In the developing roll of the present invention, for example, as shown in FIG. 1, an innermost layer 2 is formed on an outer peripheral surface of a shaft body 1, an intermediate layer 3 is formed on an outer peripheral surface of the innermost layer 2, 3 in which the outermost layer 4 is formed on the outer peripheral surface. Such a developing roll can be produced, for example, as follows.

First, using the material for forming the innermost layer 2 and the intermediate layer 3 prepared as described above, the innermost layer 2 and the intermediate layer 3 are formed in this order on the outer peripheral surface of the shaft 1 according to a conventional method. Then, a roll substrate is prepared. For example, as shown in FIG. 2, a compound-like material for forming the innermost layer 2 is poured into the lower lid 5 and the cylindrical mold 6 on which the shaft body 1 is set, and the upper lid 7 is fitted over the cylindrical mold 6. In this state, the entire roll mold is heated (vulcanization treatment, conditions: 150 to 200 ° C. × 20 to 40).
Then, the innermost layer 2 is formed. Next, the shaft 1 on which the innermost layer 2 is formed is removed from the mold, and the residue of the vulcanizing agent is removed by evaporation, if necessary. Then, a material (coating liquid) for forming the intermediate layer 3 is applied to the outer peripheral surface of the innermost layer 2, and then dried and heated (vulcanization, conditions: 120 to 200 ° C × 10 to 30).
) To form the intermediate layer 3. In this way, a roll base having the innermost layer 2 and the intermediate layer 3 formed on the outer periphery of the shaft body 1 is produced. For the coating, a conventionally known coating method such as a roll coating method, a dipping method, and a spray method can be applied.

Next, the resin composition is applied to the outer peripheral surface of the intermediate layer 3 of the roll substrate, and then dried (conditions: 40 to 150 ° C. × 5 to 60 minutes) to obtain a resin composition. The solvent inside is removed by evaporation. The coating method of the resin composition,
There is no particular limitation, and a roll coating method, a dipping method, a spray method and the like can be applied. Above all, according to the roll coating method, compared to the dipping method and the spray method, equipment with less exposure of the resin composition can be used,
There is an advantage that the quality control of the resin composition is facilitated, the required amount of the resin composition can be reduced, and waste is reduced.

Thus, a developing roll having a three-layer structure as shown in FIG. 1 can be manufactured. In the developing roll, the thickness of each layer is appropriately determined. For example,
The thickness of the innermost layer 2 is preferably set in the range of 0.5 to 10 mm, particularly preferably 3 to 6 mm. Further, the thickness of the intermediate layer 3 is preferably set in the range of 1 to 90 μm, particularly preferably 5 to 15 μm. The thickness of the outermost layer 4 is preferably set in the range of 10 to 100 μm, particularly preferably 20 to 50 μm.

As an example of the developing roll of the present invention,
Although a three-layer structure is shown in FIG. 1, the layers formed on the outer periphery of the shaft body 1 are not necessarily three layers, and an appropriate number of layers are formed. However, the outermost layer (in the case of a single layer, that layer) must be formed of the special resin composition.

Next, examples will be described together with comparative examples.

First, prior to the examples and comparative examples, a metal core (diameter: 10 mm, made of SUS304) serving as a shaft, a material obtained by adding carbon black to liquid silicone rubber as an innermost layer forming material, and a material forming an intermediate layer What prepared carbon black added to hydrogenated nitrile rubber was prepared. Then, an innermost layer and an intermediate layer were formed on the outer periphery of the shaft body according to the method described above, and a roll base was produced.

[0039]

Examples 1 to 6 and Comparative Examples 1 to 3 Tables 1 and 2 below
Were blended in the proportions shown in the same table, and were dissolved in a solvent (THF) to prepare a resin composition. And
This resin composition is applied to the outer peripheral surface of the roll base according to the above-described method (coating method: roll coating method), and then dried to form an outermost layer. As shown in FIG. Was prepared. The thickness of the innermost layer of the developing roll is 5 mm, the thickness of the intermediate layer is 10 μm,
The thickness of the outermost layer was 50 μm.

[0040]

[Table 1]

[0041]

[Table 2]

Using the developing rolls of the examples and the comparative examples thus obtained, the surface smoothness, the photoconductor contamination and the liquid stability were evaluated according to the following criteria. The results are shown in Tables 3 and 4 below.

[Surface smoothness] JIS B 0601-1
According to the method described in 994, the arithmetic average roughness (Ra) was measured. As a result, those having Ra less than 0.5 were evaluated as ○,
Those in the range of 0.5 to 1 were indicated by Δ, and those exceeding 1 were indicated by x.

[Contamination of photoreceptor] The developing roll was actually incorporated in a copying machine and copying was repeatedly performed. Thereafter, the sheet was left for a certain period of time, and copying was performed again. As a result, る も の indicates that the photoconductor was contaminated within one copy, △ indicates that the photoconductor was contaminated after 2 to 5 copies, and X indicates that the contamination was not deleted even after 6 or more copies.

[Liquid stability] The rate of change of the liquid viscosity of the solution of the resin composition was measured, and when the rate of change of the liquid viscosity was 50% or less was 11 days or more, Δ: Less than 1 day was indicated as x.

[0046]

[Table 3]

[0047]

[Table 4]

From the results shown in Tables 3 and 4, the evaluation of the surface smoothness, the contamination of the photoreceptor, and the stability of the liquid were all excellent in the developing roll of the example product as compared with the developing roll of the comparative example product. You can see that.

[0049]

As described above, the present invention relates to a developing roll in which at least one layer is formed on the outer peripheral surface of a shaft, wherein the outermost layer among the above-mentioned layers is a specific tin-based compound (component A). ). As described above, by blending the specific tin-based compound (A component) into the resin composition forming the outermost layer of the developing roll, for example, silicone and thermoplastic polyurethane resin used as the resin composition can be used. Compatibility is improved, and separation of silicone and thermoplastic polyurethane resin can be prevented. Therefore, by applying this resin composition to the roll surface and drying it, it is possible to obtain a developing roll having no surface roughness and excellent surface smoothness.

By the way, in the case of a roll coating method in which a resin composition is directly applied to the surface of a developing roll by a coating rotor, and the other portion is applied using the flow of the resin composition due to its own weight, the conventional method has been used. Is difficult to perform the roll coating method because the silicone and the thermoplastic polyurethane resin are separated at a portion to be applied using the flow of the resin composition due to its own weight of liquid dripping. However, according to the present invention, as described above, separation of the silicone and the thermoplastic polyurethane resin or the like can be prevented, so that the roll coating method, which has been difficult until now, becomes possible. Therefore, as compared with the dipping method and the spraying method, it is possible to use equipment with less exposure of the resin composition, to facilitate the quality control of the resin composition, and to reduce the required amount of the resin composition and reduce waste. There is also.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the structure of an example of a developing roll of the present invention.

FIG. 2 is a cross-sectional view illustrating a manufacturing method of an example of the developing roll of the present invention.

FIG. 3 is a configuration diagram showing a part of a copying mechanism of the electrophotographic copying machine.

FIG. 4 is a cross-sectional view illustrating a structure of a conventional developing roll.

[Explanation of symbols]

 1 shaft 2 innermost layer 3 middle layer 4 outermost layer

Continuation of the front page (72) Inventor Shoji Arimura Komaki City, Aichi Prefecture Oita Kita-gaiyama character Gezu 3600 Tokai Rubber Industries Co., Ltd.

Claims (1)

[Claims] 1. A developing roll having at least one layer formed on an outer peripheral surface of a shaft body, wherein an outermost layer among the layers is formed of a resin composition containing the following component (A). A developing roll, characterized in that: (A) A tin compound represented by the following general formula (1). Embedded image (C _n H _{2n + 1} ) ₂ —Sn— (OCOC _m H _{2m + 1} ) ₂ (1) [In the formula (1), n and m represent an integer of 1 to 20. ]