JP4433458B2 - Blade member - Google Patents

Description

  The present invention relates to a blade member, and more particularly, to an electrophotographic photosensitive member, a transfer drum and transfer belt used in a transfer process, a cleaning blade used for charging / discharging / cleaning an intermediate conveyance belt, and a charge flattened used in a development process. The present invention relates to a blade member suitable for use in a developing blade for charging, discharging and charging, and further a toner regulating blade.

  In general, in an electrophotographic process, at least charging, exposure, development, transfer, and cleaning processes are performed on an electrophotographic photosensitive member. In such an electrophotographic process, a toner image is formed and then the toner image is transferred to a transfer material. The cleaning member removes the toner on the toner image carrier, the developing member used in the developing unit, and the charging member that charges the photosensitive member. For example, polyurethane is used.

  This is because polyurethane has good abrasion resistance, has sufficient mechanical strength without adding a reinforcing agent, and is non-staining.

  Further, various means have been taken in order to reduce the friction coefficient in response to the problem that the friction coefficient is too high when contacting the photosensitive member or the like. For example, a method of applying a lubricating component to a tip portion that abuts, a method of adding a lubricating component, a method of adding a lubricating component by copolymerization, a method of performing a coating having lubricity, and the like are known.

  However, the method of applying the lubricating component does not maintain the effect, and the method of adding the lubricating component makes it difficult to adhere to the support member and causes a problem of contamination due to bleeding.

  Further, in the method of copolymerizing the lubricating component, the characteristics of the material itself are deteriorated, the wear resistance is lowered, and there is a problem of contamination by low molecular components.

  Further, for example, in the method of providing a lubricious coating layer such as a fluororesin, there is a problem that the coating layer cannot follow the deformation of the blade, and cracking or peeling is likely to occur.

  Therefore, a blade member that has a surface treatment layer that can reduce the coefficient of friction and is unlikely to crack or peel off, and that can maintain good characteristics over a long period of time has been developed and filed ( (Japanese Patent Application No. 2002-148125).

  However, there has been a problem that deterioration may occur due to repeated bending over a long period of use, and cracks may occur in some cases.

  In view of such circumstances, the present invention has a surface treatment layer that does not cause cracking or peeling even when used over a long period of time while maintaining a low coefficient of friction, and has good characteristics over a long period of time. It is an object to provide a blade member that can be maintained.

  The inventor is a surface treatment liquid containing at least one polymer selected from a fluorine-based polymer and a silicone-based polymer and an isocyanate component containing at least a polyurethane prepolymer on the surface of a rubber-like elastic body made of polyurethane rubber. When the surface treatment layer is formed, it has been found that the elasticity of the surface treatment layer can be improved, and a blade member which does not cause cracking or peeling while maintaining a low friction coefficient can be obtained.

Such a first aspect of the present invention is a blade member comprising a rubber elastic body that is used by contacting the tip of the contacted member, and the rubber elastic body is a polyurethane in which an excess isocyanate is reacted with a polyol. A surface treatment liquid comprising rubber and containing at least one polymer selected from a fluorine-based polymer and a silicone-based polymer and an isocyanate component containing at least a polyurethane prepolymer on the surface of at least the tip of the rubber elastic body. have a formed surface treatment layer, and an isocyanate component of the excess isocyanate and the surface treatment layer is in the blade member, characterized in that it is chemically bonded.

  According to a second aspect of the present invention, there is provided the blade member according to the first aspect, wherein the surface treatment liquid is obtained by further dispersing carbon black.

  A third aspect of the present invention is the blade member according to the first or second aspect, wherein the surface treatment liquid contains polyisocyanate as the isocyanate component.

  A fourth aspect of the present invention is the blade member according to any one of the first to third aspects, wherein the polymer in the surface treatment liquid is 5 to 75% by weight based on the isocyanate component. .

  According to a fifth aspect of the present invention, in the blade member according to any one of the first to fourth aspects, the rubber hardness of the rubber elastic body is 50 ° to 90 ° according to JIS A.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the surface treatment layer contains a surface treatment liquid containing a solvent that dissolves the polymer and the isocyanate component at least in the rubber elastic body. The blade member is characterized by being formed by impregnating and applying a solvent to the surface of the tip portion.

A seventh aspect of the present invention is the blade member according to any one of the first to sixth aspects, wherein the rubber elastic body is bonded and held to a conductive support member.

According to an eighth aspect of the present invention, in the seventh aspect, the surface treatment layer is formed from the surface of the rubber elastic body to the surface of the support member. The blade member is electrically connected to the support member.

  The blade member of the present invention is formed by forming a surface treatment layer with a surface treatment liquid containing at least one polymer selected from a fluorine-based polymer and a silicone-based polymer and an isocyanate component containing at least a polyurethane prepolymer. As a result, the surface treatment layer is less likely to be cracked or peeled while maintaining a low coefficient of friction while maintaining good properties, and good characteristics can be maintained over a long period of time. In addition, the surface treatment layer of the present invention can impart conductivity as necessary, and the surface treatment layer also has an effect that electrical conduction between the rubber elastic body and the support member can be achieved.

  According to the present invention, at least a part of the surface treatment layer formed on the surface of the rubber elastic body of the blade member is impregnated into the rubber elastic layer made of polyurethane and is provided integrally with the rubber elastic body. Is. That is, the surface treatment layer is formed by a surface treatment liquid containing at least one polymer of a fluorine-based polymer and a silicone-based polymer together with an isocyanate component containing at least a polyurethane prepolymer, and further, if necessary, carbon black. The surface treatment layer is formed by impregnating and applying a surface treatment liquid to which a solvent is added and removing the solvent, so that the surface treatment layer is integrally formed so as to gradually become sparse from the surface toward the inside. The Therefore, unlike a general coating layer, there is no problem such as peeling.

  Here, the isocyanate component containing at least a polyurethane prepolymer is a product obtained by reacting an excess isocyanate compound with a polyol and having an isocyanate group remaining.

  Moreover, it is good also as an isocyanate component by adding an isocyanate compound with a prepolymer. Here, as the isocyanate compound, 2,6-tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), paraphenylene diisocyanate (PPDI), 1,5-naphthalene diisocyanate (NDI) and 3,3 -Isocyanate compounds such as dimethyldiphenyl-4,4'-diisocyanate (TODI). As the isocyanate component, dimer to trimer of these isocyanate compounds can be exemplified.

  The isocyanate group of the isocyanate component containing at least the polyurethane prepolymer contained in the surface treatment liquid reacts with the urethane bond of the polyurethane rubber forming the rubber elastic body to produce allohanate, uretidione, nurate, etc. I guess that. In particular, when a rubber elastic body is molded by the centrifugal molding method, the OH component derived from the low specific gravity raw material seems to be unevenly distributed on the mirror surface side by the centrifugal force immediately after the production, and the isocyanate component of the surface treatment liquid on this surface Is impregnated, the isocyanate component is expected to be firmly bonded to the rubber elastic body. Moreover, since an isocyanate component contains a prepolymer, elasticity is provided to a surface treatment layer and it becomes difficult to produce a crack.

  Moreover, since the isocyanate component containing at least the polyurethane prepolymer in the surface treatment liquid reacts with the isocyanate of the rubber elastic layer and is firmly integrated, problems such as peeling are further avoided. The rubber elastic body of the blade member is not preferred if the polyol-derived hydroxyl group remains, and is generally synthesized with an excess of isocyanate, so that the excess isocyanate of the rubber elastic body reacts with the isocyanate component of the surface treatment liquid. Is preferred. Therefore, in consideration of this point, it is preferable to form the surface treatment layer after the blade member is manufactured and before aging to eliminate the residual isocyanate. Of course, the surface treatment layer may be formed after aging.

  Further, since the surface treatment layer of the present invention is formed from a surface treatment liquid in which a fluorine polymer or a silicone polymer is added to an isocyanate component containing at least a polyurethane prepolymer, the surface treatment layer is formed only from a fluorine polymer or a silicone polymer. Compared with a surface treatment layer formed of a coating layer, a simple isocyanate compound, a fluorine-based polymer or a silicone-based polymer, it is easily elastically deformed, and cracking of a rubber elastic body is difficult to occur.

  Since the surface treatment layer of the present invention is integrated with the surface layer of the rubber elastic layer by the reaction of the isocyanate component, it does not become contaminated even when it comes into contact with the organic photoreceptor, and a low friction coefficient is achieved. be able to.

  The surface treatment liquid used in the present invention is obtained by adding at least one kind of a fluorine-based polymer and a silicone-based polymer to an isocyanate component containing at least a polyurethane prepolymer and dissolving them in a solvent.

  Here, the fluorine-based polymer and the silicone-based polymer are those that are soluble in a predetermined solvent and can be chemically bonded by reacting with an isocyanate component containing at least a polyurethane prepolymer, and in particular, an acrylic fluorine-based polymer or an acrylic silicone. It is preferable to use a polymer.

  Here, the acrylic fluorine-based polymer is, for example, a solvent-soluble fluorine-based polymer having a hydroxyl group, an alkyl group, or a carboxyl group, and examples thereof include block copolymers of acrylic acid esters and fluorinated alkyl acrylates and derivatives thereof. be able to. The acrylic silicone polymer is a solvent-soluble silicone polymer, and examples thereof include block copolymers of acrylic acid esters and acrylic acid siloxane esters, and derivatives thereof. In the present invention, these polymers are used alone or in combination.

  Solvents that can be used in the present invention include ethyl acetate, methyl ethyl ketone (MEK), toluene, acetone, cyclohexanone, and other reactive diluents such as 2-hydroxyethyl acrylate, tetrahydrofurfuryl acrylate, 2-hydroxy. Any polymer component may be used as long as it can dissolve the polymer component used, such as ethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate, neopentyl glycol diacrylate, hexanediol diacrylate, trimethylolpropane triacrylate, and the like.

  The surface treatment layer of the present invention can be elastically deformed while maintaining a low coefficient of friction even when carbon black is used instead of the fluorine-based polymer and the silicone-based polymer as described above.

  In the present invention, the friction coefficient can be further reduced by adding carbon black in addition to the above-described polymer. Such carbon black can be fixed in the surface treatment layer by forming the surface treatment layer in a state dispersed in the surface treatment liquid.

  Here, as the carbon black, for the purpose of reducing the friction coefficient, carbon black having no conductivity may be used. Conversely, by adding conductive carbon black, the surface treatment layer Conductivity can be imparted to the. Examples of the conductive carbon black include ketjen black (manufactured by Lion Corporation) and talker black # 5500 (manufactured by Tokai Carbon Corporation).

  The content of carbon black in the surface treatment liquid is preferably 70% by weight or less with respect to the isocyanate component. If the amount is too much, problems such as dropping off are caused, which is not preferable. In order to impart conductivity, it is preferable to add 10% by weight or more.

  The polymer content in the surface treatment liquid is preferably 5 to 75% by weight, more preferably 20 to 50% by weight, based on the isocyanate component. If it is less than this, the effect of retaining the carbon black in the surface treatment layer will be small, and if it is too much, the isocyanate component will be relatively small and an effective surface treatment layer cannot be formed, which is not preferable.

  On the other hand, the polyurethane constituting the rubber elastic body of the present invention is not particularly limited as long as it is conventionally used for blades. Generally, polyester type cast polyurethane is used, and ε-caprolactone-based polyol, polyester polyol obtained by dehydration condensation of diol component and dibasic acid, etc. are polyadded with isocyanate and crosslinked. The manufacturing method is not limited, and for example, the one-shot method or the prepolymer method may be used. The rubber hardness of the rubber elastic body is preferably 50 ° to 90 ° according to JIS A.

  Here, for blades, it is preferable to react with an excess of isocyanate, and as described above, it is preferable to react this excess isocyanate with the isocyanate component of the surface treatment layer. From this point, it is preferable to form a surface treatment layer after crosslinking and before aging.

  A method for producing the blade-shaped rubber elastic body is not particularly limited, but a method of cutting a sheet produced by centrifugal molding into a predetermined size is preferably employed.

  The method for forming the surface treatment layer with the surface treatment liquid is not particularly limited, and it is sufficient that the surface treatment layer is formed at least at the tip portion that is a contact end with the contacted member of the rubber elastic body. It is needless to say that the range is not particularly limited, and only the tip surface may be used.

  The surface treatment liquid can be impregnated and applied by various methods such as application, spraying, and dipping. For example, the surface treatment liquid may be impregnated only on the tip portion or impregnated on the whole. Therefore, it is possible to impregnate and apply only the tip part or the whole in the state of the blade, or after adhering the blade shape to the support member and assembling it, impregnate and apply only the tip part or the whole. May be. Alternatively, the surface treatment layer may be formed on one surface or both surfaces of the sheet before cutting into a blade shape, and then cut. For example, the surface treatment layer may be formed on the surface during centrifugal molding. In order to form the surface treatment layer, after the impregnation application, solvent removal, that is, natural drying, forced drying, heat treatment, and the like are performed.

  FIG. 1 shows an example of a blade member after assembly by bonding to a support member. FIG. 1A shows an example in which the surface treatment layer 13A is provided only at the tip of the rubber elastic body 12 bonded to the support member 11. FIG. 1B shows only one surface of the rubber elastic body 12 bonded to the support member 11. FIG. 1C shows an example in which the rubber elastic body 12 is bonded to the support member 11 and then the surface treatment layer 13C is provided on the entire surface of the rubber elastic body 12. FIG.

  In the case of FIG. 1C, when conductive carbon black is added to the surface treatment layer 13C, the tip of the rubber elastic body 12 and the support member 11 can be electrically connected via the surface treatment layer 13C. it can.

  Hereinafter, the present invention will be described based on examples.

Example 1
After 100 parts by weight of caprolactone polyol (molecular weight 2000) and 38 parts by weight of MDI were reacted at 115 ° C. for 20 minutes, 6.1 parts by weight of 1,4-butanediol and 2.6 parts by weight of trimethylolpropane were mixed. And cured by heating in a mold kept at 140 ° C. for 40 minutes. After molding, a rubber elastic body cut into a width of 12.3 mm, a thickness of 2.0 mm, and a length of 324 mm was formed, and the rubber elastic body was bonded to a support member to obtain a blade.

(Preparation of surface treatment solution)
79 parts by weight of ethyl acetate, 10 parts by weight of polyurethane prepolymer (C-803 (50% organic solvent solution of isocyanate group-containing urethane prepolymer: isocyanate group content 2.05%) manufactured by Sanyo Chemical Industries), carbon dispersion ( 10 parts by weight of MHI-BK (carbon content 20 to 30% by weight, made by Gokoku Dye Co., Ltd.), 1 part by weight of acrylic fluoropolymer (Modiper F600 (block copolymer of methacrylic acid ester and fluorinated alkyl acrylate) made by Nippon Oil & Fats) Was dispersed and mixed in a ball mill for 3 hours.

(Blade surface treatment)
While the solution was kept at 23 ° C., the used ridge line portion of the blade was immersed in the solution for 10 seconds, and then heated in an oven kept at 50 ° C. for 1 hour to obtain a blade.

(Example 2)
(Preparation of surface treatment solution)
67 parts by weight of ethyl acetate, 20 parts by weight of polyurethane prepolymer (manufactured by C-803 Sanyo Chemical Industries), 10 parts by weight of carbon dispersion (manufactured by MHI-BK Gokoku Dye), acrylic fluoropolymer (manufactured by MODIPER F600, NOF Corporation) 3 parts by weight was dispersed and mixed with a ball mill for 3 hours.

(Blade surface treatment)
While maintaining the solution at 23 ° C., a blade similar to that in Example 1 was immersed in the solution for 10 seconds and then heated in an oven maintained at 50 ° C. for 1 hour to obtain a blade.

(Example 3)
(Preparation of surface treatment solution)
55 parts by weight of ethyl acetate, 20 parts by weight of polyurethane prepolymer (manufactured by Sanyo Chemical Industries, C-803), 20 parts by weight of carbon dispersion (manufactured by MHI-BK Gokoku Dye), acrylic fluoropolymer (manufactured by MODIPER F600, NOF Corporation) 5 parts by weight was dispersed and mixed with a ball mill for 3 hours.

(Blade surface treatment)
While maintaining the solution at 23 ° C., a blade similar to that in Example 1 was immersed in the solution for 10 seconds and then heated in an oven maintained at 50 ° C. for 1 hour to obtain a blade.

Example 4
(Preparation of surface treatment solution)
57 parts by weight of ethyl acetate, 20 parts by weight of polyurethane prepolymer (manufactured by Sanyo Chemical Industries, C-803), 20 parts by weight of carbon dispersion (manufactured by MHI-BK Gokoku Dye), acrylic fluoropolymer (manufactured by MODIPER F600, NOF Corporation) 3 parts by weight was dispersed and mixed with a ball mill for 3 hours.

(Blade surface treatment)
While maintaining the solution at 23 ° C., a blade similar to that in Example 1 was immersed in the solution for 10 seconds and then heated in an oven maintained at 50 ° C. for 1 hour to obtain a blade.

(Comparative Example 1)
An untreated product that was not subjected to surface treatment on the blade of Example 1 was designated as Comparative Example 1.

(Comparative Example 2)
(Preparation of surface treatment solution)
68.5 parts by weight of ethyl acetate, 15 parts by weight of an isocyanate compound (MR-400 (polymethylene polyphenyl polyisocyanate) manufactured by Nippon Polyurethane Co., Ltd.), 15 parts by weight of a carbon dispersion (manufactured by MHI-BK Gokoku Color Co., Ltd.), acrylic fluoropolymer 1.5 parts by weight (Modiper F600 manufactured by Nippon Oil & Fats Co., Ltd.) was dispersed and mixed with a ball mill for 3 hours.

(Blade surface treatment)
While maintaining the solution at 23 ° C., a blade similar to that in Example 1 was immersed in the solution for 10 seconds and then heated in an oven maintained at 50 ° C. for 1 hour to obtain a blade.

(Test Example 1) Measurement of friction coefficient As shown in FIG. 2 using urethane sheets (thickness 2 mm × width 5 mm × length 50 mm) treated in the same manner as the blades of Examples 1 to 4 and Comparative Examples 1 and 2. The coefficient of friction was measured by the method.

  A urethane sheet 22 is placed on a Teflon (registered trademark) plate 21, and a 100 gf load is applied to the urethane sheet 22 via a Teflon (registered trademark) roller (inner diameter 16 mm × outer diameter 20 mm) 23, and the tensile speed is increased Carrying a polycarbonate sheet 24 (CFEM manufactured by Mitsubishi Engineering Plastics Co., Ltd.) having a thickness of 0.25 mm at 50 mm / sec, a load Q (N) measured by a load cell attached to one end of the polycarbonate sheet 24 is obtained. Calculation was performed according to the following formula. The measurement was performed in a normal temperature and normal humidity environment (NN: 20 ° C., 40% RH). The results are shown in Table 1.

[Equation 1]
μ = Q (N) / (100 gf × 0.0098)

(Test Example 2) Bending test A urethane sheet (thickness 2 mm × width 15 mm × length 50 mm) treated in the same manner as the blades of Examples 1 to 4 and Comparative Example 2 was wound around a core metal having an outer diameter of 9 mm with 22 clips. What was hold | maintained for time was observed with the microscope of 450 times (VH-Z450 by Keyence Corporation), and when the crack was not observed, it was set as (circle), and when the crack was observed, the intensity | strength with respect to bending was evaluated. The results are shown in Table 1.

(Test Example 3) Tensile test The urethane sheet (thickness 2 mm × width 5 mm × length 100 mm) treated in the same manner as the blades of Examples 1 to 4 and Comparative Example 2 was gripped and stretched 50%. While maintaining the state, the strength of the surface treatment layer was evaluated by observing with a 450 × microscope (VH-Z450, manufactured by Keyence Corporation), with ○ when the crack was not observed and × when the crack was observed. The results are shown in Table 1.

(Test Example 4)
When the blades of Examples 1 to 4 and Comparative Examples 1 and 2 are attached to an actual machine (manufactured by Fuji Xerox: Docu Center color 400) as a cleaning blade, and JD paper (full color copier paper for double-sided copying) is fed. Generation of squeal (abnormal noise) was confirmed by a sensory test. The test was conducted under a high temperature and high humidity environment (HH: 28 ° C., 85% RH). The results are shown in Table 1.

  From this result, it was found that the cleaning blades of Examples 1 to 4 and Comparative Example 2 showed a lower coefficient of friction than the untreated Comparative Example 1.

  Moreover, Examples 1-4 showed the favorable characteristic in both the bending test and the tension test, and it turned out that elastic force is high. On the other hand, in Comparative Example 2, it was found that the results of the bending test and the tensile test were poor and the elastic force was low.

  As a result of Test Example 4 used in the actual machine, no squeak occurred until 500 sheets were passed in Examples 1, 3 and 4 and 2000 sheets were passed in Example 2, but in Comparative Examples 1 and 2, The squeal occurred from the beginning because of its low elasticity.

It is sectional drawing which shows the example of the blade member which concerns on this invention. It is explanatory drawing which shows the mode of the measurement of the test example 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Support member 12 Rubber elastic body 13A-13C Surface treatment layer 21 Teflon (registered trademark) plate 22 Urethane sheet 23 Teflon (registered trademark) roller 24 Polycarbonate sheet

Claims (8)

A blade member comprising a rubber elastic body that is used by contacting a tip part thereof to a contacted member, wherein the rubber elastic body is made of polyurethane rubber obtained by reacting an excess isocyanate with a polyol, and at least the rubber elastic body wherein the surface of the tip portion, at least a one polymer selected from the fluorine-based polymers and silicone-based polymers, have a surface treatment layer formed by the surface treatment liquid containing an isocyanate component comprising at least a polyurethane prepolymer, The blade member, wherein the excess isocyanate and the isocyanate component of the surface treatment layer are chemically bonded . The blade member according to claim 1, wherein the surface treatment liquid is obtained by further dispersing carbon black. The blade member according to claim 1 or 2, wherein the surface treatment liquid contains polyisocyanate as the isocyanate component. 4. The blade member according to claim 1, wherein the polymer in the surface treatment liquid is 5 to 75% by weight with respect to the isocyanate component. 5. The blade member according to claim 1, wherein the rubber elastic body has a rubber hardness of 50 ° to 90 ° according to JIS A. 6. In any one of Claims 1-5, the said surface treatment layer impregnates and applies the surface treatment liquid containing the solvent which melt | dissolves the said polymer and the said isocyanate component to the surface of at least the said front-end | tip part of the said rubber elastic body, A blade member formed by removing a solvent. The blade member according to any one of claims 1 to 6 , wherein the rubber elastic body is adhered and held to a conductive support member. 8. The surface treatment layer according to claim 7 , wherein the surface treatment layer is formed from the surface of the rubber elastic body to the surface of the support member, thereby electrically connecting the tip of the rubber elastic body and the support member. A blade member characterized by being made.

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