JP5060158B2 - Cleaning blade for electrophotographic apparatus and manufacturing method thereof - Google Patents

Description

The present invention relates to a cleaning blade for an electrophotographic apparatus and a method for manufacturing the same.

In an electrophotographic apparatus using plain paper as recording paper, generally, an electrostatic charge is applied to the surface of the image carrier by discharge, and an image is exposed on the surface to form an electrostatic latent image. Copying is performed by attaching and developing the electrostatic latent image, transferring the toner image onto a recording sheet, and finally heating and pressing the recording sheet onto which the toner image has been transferred to fix the toner on the recording sheet. .

Therefore, in order to sequentially copy on a plurality of recording papers, it is necessary to remove the toner remaining on the surface of the image carrier after the toner image is transferred from the image carrier to the recording paper in the above-described process. Such toner removal is usually performed by a cleaning blade for an electrophotographic apparatus. As a cleaning blade for an electrophotographic apparatus, a support member made of a metal plate, an elastic rubber member, and an adhesive layer for joining the support member and the elastic rubber member are widely used.

In recent years, there has been a demand for higher-quality printed materials in electrophotographic apparatuses, and it is likely that polymerized toners having a spherical shape (true spherical shape, irregular shape) and a small particle size will be used compared to conventional pulverized toners. It has become. Since such a polymerization toner is easy to roll, cleaning failure due to slipping of residual toner is likely to occur.

For this reason, when a conventional cleaning blade is applied to an electrophotographic apparatus using polymerized toner, there arises a problem that sufficient cleaning properties cannot be obtained, and cleaning properties particularly at low temperatures and low humidity are deteriorated.

Patent Documents 1 to 4 disclose an electrophotographic apparatus cleaning blade having an elastic rubber member having a two-layer structure including an edge layer and a base layer and a support member. However, when the cleaning blade disclosed herein is used, the cleaning property (particularly under low temperature and low humidity) may be inferior.
JP 2003-29594 A JP 2002-214989 A JP 2002-214990 A JP 2007-11047 A

In view of the above situation, the present invention has excellent cleaning properties (especially cleaning under low temperature and low humidity) even when a polymerization toner having a spherical shape (true spherical shape, irregular shape) and a small particle size is used. It is an object of the present invention to provide a cleaning blade for an electrophotographic apparatus having a property.

The present invention is an electrophotographic apparatus cleaning blade having an elastic rubber member and a support member, wherein the elastic rubber member has a multilayer structure of two or more layers having an edge layer and a layer other than the edge layer, And in the three-point bending test with the edge layer on the upper side, the hysteresis loss (B / A) of deflection and bending load is expressed by the following formula (1);
0.2 ≦ B / A ≦ 0.4 (1)
The cleaning blade for an electrophotographic apparatus is characterized by comprising a material satisfying the above characteristics.

The elastic rubber member has a two-layer structure composed of an edge layer and a base layer, and in a three-point bending test with the edge layer on the upper side, the hysteresis loss (B / A) of deflection and bending load is expressed by the following formula: (1);
0.2 ≦ B / A ≦ 0.4 (1)
It is preferable to be made of a material satisfying these characteristics.

The edge layer is made of polyurethane containing polycaprolactone polyol and / or polyester polyol as a polyol component, and at least one layer other than the edge layer is made of polyurethane containing polycaprolactone polyol and / or polyester polyol as a polyol component. It is preferable.

The present invention also relates to a method for manufacturing the above-described cleaning blade for an electrophotographic apparatus using a centrifugal molding method, the step (I) of manufacturing a molded body of silicone rubber inside a mold, and the above step (I). Step (II) for producing a molded body constituting the edge layer of the elastic rubber member on the molded body of the silicone rubber obtained in step (b), and on the molded body constituting the edge layer obtained in the step (II) And a step (III) for producing a molded body constituting a layer other than the edge layer of the elastic rubber member, and the molded body constituting the obtained elastic rubber member is a three-point bending test with the edge layer on the upper side. The hysteresis loss (B / A) of deflection and bending load is expressed by the following formula (1);
0.2 ≦ B / A ≦ 0.4 (1)
It is also a method for manufacturing a cleaning blade for an electrophotographic apparatus, which is made of a material that satisfies the above characteristics.

In the above production method, the molded product of the silicone rubber includes an organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups bonded to silicon atoms, and an organohydropolyene polymer having at least two hydrogen atoms bonded to silicon atoms. It is preferably obtained from an addition-curable silicone rubber composition containing siloxane and a platinum-based catalyst.
Hereinafter, the present invention will be described in detail.

[Cleaning blade for electrophotographic equipment]
The elastic rubber member of the cleaning blade for electrophotographic apparatus (hereinafter also simply referred to as “cleaning blade”) of the present invention has a multilayer structure of two or more layers having an edge layer and layers other than the edge layer. Further, the elastic rubber member is made of a material satisfying a characteristic that a hysteresis loss (B / A) of deflection and bending load is B / A <0.5 in a three-point bending test with the edge layer on the upper side. Since the elastic rubber member has such hysteresis loss characteristics, when the cleaning blade of the present invention is used, a spherical (true spherical, irregular shape) toner with a small particle size is used as the toner. Even so, excellent cleaning properties (particularly under low temperature and low humidity) are exhibited.

When the cleaning blade for an electrophotographic apparatus of the present invention is used, the reason why excellent cleaning properties (especially under low temperature and low humidity) can be obtained is not clear, but it is presumed that the effect described below is exhibited. The

FIG. 1 (i) shows an example of the cleaning blade for an electrophotographic apparatus of the present invention having an elastic rubber member having a multilayer structure of two or more layers, and an edge layer and a base layer (layers other than the edge layer). It has an elastic rubber member having a two-layer structure. The cleaning blade of FIG. 1 (i) has an elastic rubber member 11, a support member 12, and an adhesive layer 13. The elastic rubber member 11 has a two-layer structure of an edge layer 21 and a base layer 22. ing. FIG. 1 (ii) is a schematic diagram showing the cleaning behavior of the surface of the image carrier (counter member) 14 when the cleaning blade having such a configuration is used. 21 shows a state in which the edge 21 scrapes residual toner (not shown) on the counterpart material 14.

When a cleaning blade is applied to an electrophotographic apparatus using a polymerization toner, there are many cases where the cleaning performance is deteriorated particularly at low temperature and low humidity. If the hysteresis loss characteristic shows a small value of less than 0.5 when a bending test is performed, the rubber elasticity of the elastic rubber member as a whole can be maintained, thereby improving the cleaning property particularly under low temperature and low humidity. It is guessed that has become possible.

An excellent cleaning property (particularly under low temperature and low humidity) is not only the case of the elastic rubber member having the two-layer structure shown in FIG. 1 (i), but also an elastic rubber member having a structure of three or more layers (further having other layers). Can also be obtained. In this case, it is presumed that the same function as described above is exhibited. Therefore, in the present invention, it is possible to obtain excellent cleaning properties (especially under low temperature and low humidity) even when the above-mentioned polymerization method toner is used by exerting the function described above. Inferred.

The cleaning blade for an electrophotographic apparatus has an elastic rubber member and a support member.
The elastic rubber member scrapes off the toner and external additives on the surface of the image carrier when the cleaning blade is used. The elastic rubber member has a multilayer structure of two or more layers having an edge layer and a layer other than the edge layer.

The edge layer is a layer in the blade length direction that is located on the side of the elastic rubber member in contact with the mating member. On the other hand, the layers other than the edge layer are layers in the blade length direction other than the edge layer in the elastic rubber member having a multilayer structure of two or more layers. The layer other than the edge layer may have only one layer, or may have one or more layers other than the layer.

The elastic rubber member is made of a material satisfying a characteristic that a hysteresis loss (B / A) of deflection and bending load is B / A <0.5 in a three-point bending test with the edge layer on the upper side. By using an elastic rubber member having the above characteristics, excellent cleaning properties (particularly under low temperature and low humidity) can be obtained. Such an effect is presumed to be obtained by exhibiting the above-described action.

In this specification, the three-point bending test is a method according to JIS K 7203 (bending test method for hard plastic (1982)). The following tests are conducted under the conditions described.
Test piece dimensions: length 40 mm, width 5.0 mm, height 2.0 mm
Test speed (compression speed): 20 mm / min Deflection: 3.0 mm
Distance between fulcrums: 32mm

In the three-point bending test with the edge layer on the upper side, the elastic rubber member having a multi-layer structure is left in a test apparatus so that the surface on the edge layer side is the upper side (the side pressed by the pressure wedge). This is a test to be performed, and the bending load is continuously measured within a range of deflection of 0 to 3.0 mm. For example, in the elastic rubber member 11 of FIG. 1, the elastic rubber member 11 is allowed to stand so that the surface 23 on the edge layer side is on the upper side, and a pressure wedge is pressed against the surface 23 in the arrow direction 24. The bending load is continuously measured while the deflection is continuously displaced within the range of 0 to 3.0 mm. The three-point bending test in the present invention is performed by displacing the deflection from 0 mm to 3.0 mm (bending) and then displacing from 3.0 mm to 0 mm (returning the bending).

In the three-point bending test, the hysteresis loss (B / A) of deflection and bending load is the ratio B / A (area ratio) of the following B (area) to the following A (area).
A: Obtained by a test in a three-point bending test in which an elastic rubber member placed in a test apparatus is displaced (bend) at a test speed (compression speed) of 20 mm / min from a state of deflection of 0 mm to a state of deflection of 3.0 mm. Area value according to the relationship curve of deflection (mm) and bending load (gf).
B: A three-point bending test in which the elastic rubber member displaced to a state of deflection of 3.0 mm according to the above-mentioned area A and further displaced to a state of deflection of 0 mm at a test speed (compression speed) of 20 mm / min (return) And the difference from the area value according to the relationship curve of the deflection (mm) and bending load (gf) obtained in the test.

The hysteresis loss (B / A) will be described more specifically with reference to FIG.
FIG. 2 is an example of a relationship curve of deflection (d) and bending load (F) obtained in the three-point bending test in the present invention.
In FIG. 2, first, the deflection-bending load curve [(A) → (B) obtained by continuously measuring the bending load value while the deflection (d) is displaced (bending) from 0 mm to 3.0 mm. → (c) curve (straight line in the example of FIG. 2)] is shown. A is an area value surrounded by a straight line of bending load (F) = 0 (gf), deflection (d) = 3.0 (mm), and (b) → (b) → (c). (Area value of hatched portion).

FIG. 2 further shows the deflection obtained by continuously measuring the bending load value while displacing (bending) the deflection (bending) described above (d) to the deflection of 0 mm (returning) to the deflection of 0 mm. -A bending load curve [curve of (c) → (d) → (e)] is shown. B is an area value (the area value of the vertical line part (the vertical line and the vertical line)) surrounded by the curve (A) → (B) → (C) and the curve (C) → (D) → (E). The area value of the portion where the diagonal lines intersect))). In other words, B is the area value of A− [straight line of bending load (F) = 0 (gf), deflection (d) = 3.0 (mm), and (c) → (d) → ( The area value surrounded by the curve of (e)].

In the present invention, the value of the hysteresis loss (B / A) is less than 0.5, but if B / A ≧ 0.5, the cleaning property (especially under low temperature and low humidity) may be deteriorated. The elastic rubber member preferably satisfies the characteristics of 0.2 ≦ B / A ≦ 0.4.

The A (area value) is preferably 15 to 45 (mm × gf). If it is less than 15, the pressure contact force required for cleaning may not be maintained (the toner may slip through). If it exceeds 45, the pressure contact force becomes too large, and abnormal noise generation and inversion turning easily occur.

In the present invention, the elastic rubber member satisfying the characteristic of the above formula (1) can be obtained by appropriately selecting the material constituting the edge layer and the material constituting the layer (base layer or the like) joined to the support member. . The elastic rubber member having A within the above preferred range can also be obtained by appropriately selecting the material constituting the edge layer and the material constituting the layer (base layer or the like) joined to the support member.

The “layer to be bonded to the support member” is a layer to be bonded to the support member among the layers of the elastic rubber member having a multilayer structure, for example, two layers including the edge layer 21 and the base layer 22 in FIG. In the cleaning blade having the elastic rubber member having the structure, the base layer 22 corresponds, and the layer 22 is bonded to the support member 12 through the adhesive layer 13. On the other hand, the edge layer 21 is not joined to the support member 12. Here, joining means being in contact with each other.

The elastic rubber member has a ratio (a / (a + b) between the thickness (a) of the edge layer and the sum (a + b) of the thickness (a) of the edge layer and the total thickness (b) of the layers other than the edge layer. )) Is preferably 0.03 to 0.97. Thereby, it is more preferable that it is 0.07-0.40 which can acquire the outstanding cleaning property (especially under low temperature low humidity).

It is preferable that the thickness (a) of the edge layer is 0.1 to 2.9 mm. Thereby, the outstanding cleaning property (especially under low temperature and low humidity) can be obtained. More preferably, it is 0.2 to 0.4 mm.

The elastic rubber member has a two-layer structure composed of an edge layer and a base layer, and in a three-point bending test with the edge layer on the upper side, the hysteresis loss (B / A) of deflection and bending load is the above formula. It is preferable that it consists of a material satisfy | filling the characteristic of (1). In this case, the base layer corresponds to a layer other than the edge layer, and there is only one layer other than the edge layer. In the elastic rubber member having the two-layer structure of the edge layer and the base layer, the hysteresis loss (B / A) is a value measured by the same method as the bending test described above.

The base layer is a blade lengthwise layer located on the support member side of the elastic rubber member having a two-layer structure. In the cleaning blade of FIG. 1, the edge layer is not bonded to the support member, and the base layer is bonded to the support member via an adhesive layer.

In the case where the elastic rubber member has a two-layer structure composed of an edge layer and a base layer, the same problem as described above occurs unless the characteristic of the formula (1) is satisfied. Moreover, the preferable range of hysteresis loss (B / A) and A is the same as the range described in layers other than the edge layer. Further, the ratio between the thickness of the edge layer and the sum of the thickness of the edge layer and the base layer, and the preferable range of the thickness of the edge layer are the same (in this case, the thickness of the base layer is the total thickness of the layers other than the edge layer described above). (Applicable to (b)).

It is preferable that at least one of the edge layer and the layer other than the edge layer (base layer or the like) is made of polyurethane. Thereby, the outstanding cleaning property (especially under low temperature and low humidity) can be obtained. Examples of the polyurethane forming the elastic rubber member include those obtained by reacting polyol, polyisocyanate and, if necessary, a crosslinking agent.

It does not specifically limit as said polyol, For example, a polyester polyol, polyether polyol, polycaprolactone polyol etc. can be mentioned. Of these, polyester polyols and polycaprolactone polyols are preferable, and polycaprolactone polyols are particularly preferable because excellent cleaning properties (particularly under low temperature and low humidity) can be obtained. These may be used alone or in combination of two or more.

The polyol preferably has a number average molecular weight of 1000 to 3000. By using a polyol within the above range, excellent cleaning properties (particularly under low temperature and low humidity) can be obtained.

As said polyester polyol, what can be obtained by making dicarboxylic acid and glycol react according to a conventional method can be mentioned, for example.
Examples of the dicarboxylic acid include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, and sebacic acid, and oxycarboxylic acids such as oxybenzoic acid. Examples thereof include acids and ester-forming derivatives thereof. Examples of the glycol include aliphatic glycols such as ethylene glycol, 1,4-butanediol, diethylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, and triethylene glycol. Examples include alicyclic glycols such as 1,4-cyclohexanedimethanol, aromatic diols such as p-xylene diol, polyoxyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Polyester polyols based on these have a linear structure, but may be branched polyesters using a trivalent or higher valent ester-forming component. Among them, the aliphatic dicarboxylic acid is preferable as the dicarboxylic acid, and adipic acid is particularly preferable because excellent cleaning properties (particularly under low temperature and low humidity) can be obtained. As the glycol, aliphatic glycol is preferable, and ethylene glycol and 1,4-butanediol are more preferable.

Examples of the polyether polyol include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymers thereof.

Examples of the polycaprolactone polyol include those that can be obtained by ring-opening addition of ε-caprolactone using a low molecular weight glycol as an initiator in the presence of a catalyst. As the low molecular weight glycol, divalent alcohols such as ethylene glycol, propylene glycol, 1,3-butylene glycol and neopentyl glycol and trivalent alcohols such as trimethylene glycol and glycerin are preferably used. Examples of the catalyst include organic titanium compounds such as tetrabutyl titanate, tetrapropyl titanate, and tetraethyl titanate, tin compounds such as tin octylate, dibutyltin oxide, dibutyltin laurate, stannous chloride, and stannous bromide. Preferably used. In addition to the above ε-caprolactone, other cyclic lactones such as trimethylcaprolactone and valerolactone may be partially mixed.

It does not specifically limit as said polyisocyanate, A conventionally well-known thing can be used, For example, aliphatic isocyanate, alicyclic isocyanate, aromatic isocyanate etc. can be mentioned. Of these, aromatic isocyanates are preferred from the standpoint that excellent cleaning properties (particularly low temperature and low humidity) can be obtained.

Examples of the aliphatic isocyanate include 1,6-hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate. Moreover, the isocyanurate body of hexamethylene diisocyanate and isophorone diisocyanate, the biuret body, the modified body of an adduct body, etc. can be mentioned. Examples of the alicyclic isocyanate include alicyclic diisocyanates such as isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, norbornane diisocyanate (NBDI), and the like. Examples of the aromatic isocyanate include tolylene diisocyanate (TDI), phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate, xylylene diisocyanate (XDI), carbodiimide-modified MDI, and urethane. Examples include modified MDI. Among the above polyisocyanates, MDI and urethane-modified MDI are preferred, and MDI is particularly preferred because excellent cleaning properties (particularly under low temperature and low humidity) can be obtained.

Examples of the crosslinking agent used in the polyurethane as necessary include ethylene glycol, propylene glycol, butanediol, hexanediol, diethylene glycol, trimethylolpropane, glycerin, hydrazine, ethylenediamine, diethylenetriamine, 4,4'-diaminodiphenylmethane. 4,4'-diaminodicyclohexylmethane, N, N-bis (2-hydroxypropyl) aniline, water and the like. Among these, ethylene glycol, 1,4-butanediol, trimethylolpropane, and N, N-bis (2-hydroxypropyl) aniline are preferable because excellent cleaning properties (particularly under low temperature and low humidity) can be obtained. In particular, it is preferable to use 1,4-butanediol and trimethylolpropane in combination.

The polyurethane can be produced by a known method using the above raw materials. For example, a catalyst is used as necessary in a suitable organic solvent, and the equivalent ratio of each raw material is NCO / OH = 1.02. It can be produced by adjusting to 1.18 and reacting, or melting reaction without solvent. Moreover, it can manufacture by the method of making all the raw materials react simultaneously, the prepolymer method, etc.

The method for molding the elastic rubber member made of polyurethane is not particularly limited. For example, normal pressure casting, reduced pressure casting, centrifugal molding, rotational molding, extrusion molding, injection molding, reaction injection molding (RIM), spin coating Etc. Among these, it is preferable to manufacture by molding by centrifugal molding from the viewpoint that excellent cleaning properties (particularly under low temperature and low humidity) can be obtained.

The support member has a function of supporting the elastic rubber member. The support member is not particularly limited, and a conventionally known member can be used, and examples thereof include a rigid metal, an elastic metal, a plastic, a ceramic, and the like. Among these, a rigid metal is preferable.

The cleaning blade preferably has an adhesive layer. The adhesive layer is a layer provided between the support member and the elastic rubber member, and is a layer having a function of bonding both members. The adhesive layer can be formed by, for example, an EVA-based, polyamide-based, polyurethane-based hot melt adhesive, a curable adhesive, a bonding method using a double-sided tape, or sandwiching with a sheet metal. Especially, it is preferable that the said adhesive bond layer is formed using a hot-melt-adhesive from the point which can acquire the outstanding cleaning property (especially low temperature under low humidity).

The cleaning blade can be suitably used not only in a conventional pulverized toner but also in an electrophotographic apparatus using a polymerization toner. The polymerization toner is not particularly limited. For example, Japanese Patent No. 2537503 (emulsion polymerization aggregation method), Japanese Patent Application Laid-Open No. 2002-351143 (solution suspension + polymerization method), Japanese Patent Application Laid-Open No. 9-15902 (solution). Conventionally known ones described in (Suspension method) and the like can be used. Examples of the polymerization toner include those having a spherical shape (true spherical shape, irregular shape) and an average particle diameter of 5 to 8 μm. The average particle diameter is a value (D50) obtained by a known method.

[Method of manufacturing cleaning blade for electrophotographic apparatus]
The method for manufacturing the cleaning blade for an electrophotographic apparatus described above is not particularly limited, and can be manufactured by a conventionally known manufacturing method for a blade having an elastic rubber member having a multilayer structure of two or more layers. The production method described is preferred. Such a manufacturing method is also one aspect of the present invention.

The method for producing a cleaning blade for an electrophotographic apparatus according to the present invention is a production method using a centrifugal molding method, which comprises a step (I) of producing a molded product of silicone rubber inside a mold, and the above step (I). Step (II) for producing a molded body constituting the edge layer of the elastic rubber member on the molded body of the silicone rubber obtained in step (b), and on the molded body constituting the edge layer obtained in the step (II) And a step (III) of producing a molded body constituting a layer other than the edge layer of the elastic rubber member, and the molded body constituting the obtained elastic rubber member is in a three-point bending test with the edge layer on the upper side. In this method, the hysteresis loss (B / A) of deflection and bending load satisfies a characteristic of B / A <0.5.

In the manufacturing method of the present invention, since a mirror-like surface is formed on the air side surface (the surface that was inside when centrifugal molding was performed) of the silicone rubber layer that was molded first, the edge layer that was subsequently molded The silicone rubber contact surface is also mirror-like. Therefore, the use surface of the elastic rubber member can be a silicone rubber contact surface of the edge layer. As a result, it is possible to reduce surface defects caused by foreign matters such as bubbles and dust that are involved in casting, and improve productivity.

In addition, since silicone rubber is cured in a form that absorbs the vibration of the mold, the inner air side surface is mirror-like and has high runout accuracy (from the center axis to the inner surface of the mold when the mold rotates). A silicone rubber layer having a difference between the maximum value and the minimum value of the distance is formed. As a result, an elastic rubber member material layer having good thickness accuracy of 0.1 mm or less (difference between the maximum value and the minimum value of the sheet thickness for one molding) can be produced. The thickness accuracy is preferably 0.05 mm or less.

Furthermore, according to the above production method, an elastic rubber member having a multi-layer structure having an edge layer and a layer other than the edge layer and satisfying the characteristic of the above formula (1) can be obtained. Even when a polymerization toner is used, excellent cleaning properties (particularly under low temperature and low humidity) can be obtained.

The production method of the present invention is a method using a centrifugal molding method. First, a step of producing a molded body of silicone rubber is performed inside a mold of a centrifugal molding machine (step (I)). A conventionally well-known thing can be used as a molding machine and metal mold | die used for a centrifugal molding method. Production of a silicone rubber molded body is performed, for example, by pouring the thermosetting material constituting the silicone rubber molded body into the inner surface of a heated cylindrical mold that rotates at high speed, and heating and curing the material. Can do.

Through the step (I), a silicone rubber layer (planar silicone rubber molded sheet) is formed on the inner surface of the mold. Since the molded product of silicone rubber is excellent in releasability, the elastic rubber member material layer formed thereon can be easily peeled off without using a release agent.

In the step (I), the silicone rubber molded product is preferably obtained from an addition-curable silicone rubber composition, and the addition-curable silicone rubber composition includes an aliphatic unsaturated carbon bond bonded to a silicon atom. An organopolysiloxane having at least two hydrogen groups, an organohydropolyene polysiloxane having at least two hydrogen atoms bonded to silicon atoms, and a platinum catalyst are preferred. In this case, a molded body of silicone rubber having high runout accuracy is formed, and an elastic rubber member having good thickness accuracy can be produced. Moreover, the surface defect in the edge layer of an elastic rubber member can be improved. Furthermore, excellent cleaning properties (especially under low temperature and low humidity) can be obtained with the obtained cleaning blade. Moreover, when the composition to which the organic solvent is not added is used, the hygiene of the working environment can be kept good without harming the health of the worker.

The organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups bonded to the silicon atom is a component that serves as a base polymer of the addition-curable silicone rubber composition, and has an average composition formula (2): R ¹ _a R a is preferably _{^{2 b SiO [4- (a +}} b)] / 2 the compound represented by. In the above formula (2), R ¹ represents a monovalent aliphatic unsaturated hydrocarbon group having 2 to 10 carbon atoms. Preferably it is C2-C6. Specific examples of R ¹ are preferably alkenyl groups such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, isobutenyl group, and more preferably vinyl group.

R ² represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms. Preferably it is C1-C8. However, the R ² is the aliphatic unsaturated hydrocarbon group are excluded. Specific examples of R ² include, for example, alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, hexyl group, cyclohexyl group, octyl group; phenyl group, tolyl Aryl groups such as aralkyl groups; aralkyl groups such as benzyl groups and phenylethyl groups; those in which some or all of the hydrogen atoms are substituted with halogen atoms such as fluorine, chlorine, bromine or cyano groups (chloromethyl) Group, bromoethyl group, trifluoropropyl group, cyanoethyl group, etc.). Of these, a methyl group, a phenyl group, and a trifluoropropyl group are preferable, and a methyl group is more preferable. R ² is preferably more than 92 mol% are methyl groups, it may be substantially all methyl groups. Moreover, when solvent resistance is calculated | required, other groups, such as a 3,3,3- trifluoropropyl group, can be used together suitably according to a required characteristic.

A and b represent numbers satisfying the relationship of 0 <a ≦ 1, 1 <b <3, 1 <a + b <3, respectively, preferably 0.0001 ≦ a ≦ 0.5, 1.8 ≦ b ≦ 2.2 and 1.8 ≦ a + b ≦ 2.25. In the organopolysiloxane represented by the above formula (2), two or more of the above aliphatic unsaturated hydrocarbon groups are bonded to a silicon atom in one molecule. The aliphatic unsaturated hydrocarbon group may be bonded to the silicon atom at the end of the molecular chain, may be bonded to one of the silicon atoms in the molecular chain, and further bonded to both. Also good. Among these, in the organopolysiloxane represented by the above formula (2), the aliphatic unsaturated hydrocarbon group (preferably an alkenyl group, more preferably a vinyl group) is bonded to silicon atoms at both ends of the molecular chain. Those are preferred.

The organopolysiloxane may have any of a straight chain, branched chain or cyclic skeleton, but the main chain portion has a diorganosiloxane unit as a repeating unit, and the molecular chain terminal has a triorganosiloxane unit. What it has is preferable. Examples of the triorganosiloxane unit (triorganosiloxane unit in which only a substituted or unsubstituted monovalent hydrocarbon group is bonded to a silicon atom) include vinyl groups such as a trimethylsiloxane unit, a dimethylphenylsiloxane unit, and a methyldiphenylsiloxane unit. What does not contain; What contains vinyl groups, such as a dimethyl vinyl siloxane unit and a methylphenyl vinyl siloxane unit, can be mentioned, Especially, the thing containing a vinyl group is preferable.

The degree of polymerization of the organopolysiloxane (number of Si atoms in the molecule) is preferably 10 to 20000, and more preferably 100 to 15000. If it is less than 10, a cured product having sufficient mechanical strength (strength / elongation / hardness) may not be obtained. If it exceeds 15000, the fluidity of the resulting silicone rubber composition may be deteriorated.

The organohydrodiene polysiloxane having at least two hydrogen atoms bonded to the silicon atom is produced by the addition reaction (hydrosilylation) of the hydrogen atom bonded to the silicon atom with the aliphatic unsaturated hydrocarbon group of the organopolysiloxane. It functions as a crosslinking agent for organopolysiloxane.

The organohydrodiene polysiloxane is preferably a compound represented by an average composition formula (3): R ³ _c H _d SiO _{[4- (c + d)] / 2} . R ³ represents the same group as R ² described above. Of these, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 4 carbon atoms is preferable. From the viewpoints of ease of synthesis and cost, an alkyl group is preferable, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a tert-butyl group are more preferable, and a methyl group is particularly preferable.

The above c and d represent numbers satisfying the relationship of 0.8 ≦ c ≦ 2.2, 0.002 ≦ d ≦ 1, and 0.8 <c + d <3, respectively, preferably 1 ≦ c ≦ 2.2. , 0.01 ≦ d ≦ 1, 1.8 ≦ c + d ≦ 2.5. The organohydrodiene polysiloxane represented by the above formula (3) may be linear, branched or cyclic in skeleton, and contains a diorganohydrodienesiloxane unit and a SiO ₂ unit, It may be a resinous material having a three-dimensional network structure containing triorganosiloxane units or diorganosiloxane units as appropriate.

The organohydrodiene polysiloxane is a compound in which a SiH group is formed by bonding at least 2, preferably 3 or more hydrogen atoms in a molecule to a silicon atom. In this case, the H atom may be bonded to the Si atom at the end of the molecular chain, may be bonded to any Si atom in the middle of the molecular chain, or may be bonded to both. The degree of polymerization of the organohydrodiene polysiloxane (number of Si atoms in the molecule) is preferably 3 to 400, and particularly preferably 4 to 300.

Specific examples of the above-mentioned organohydrodiene polysiloxane include, for example, methylhydrogencyclopolysiloxane, methylhydrodienesiloxane / dimethylsiloxane cyclic copolymer, trimethylsiloxy group-blocked methylhydrogenpolysiloxane, trimethylsiloxy group at both ends Blocked dimethylsiloxane / methylhydrodienesiloxane copolymer, both ends dimethylhydrosiloxy group-blocked dimethylpolysiloxane, both ends dimethylhydrosiloxy group-blocked dimethylsiloxane / methylhydrogenenesiloxane copolymer, both ends trimethylsiloxy group-blocked methyl Hydrodienesiloxane-diphenylsiloxane copolymer, both ends trimethylsiloxy-blocked methylhydrodienesiloxane-diphenylsiloxy Down-dimethylsiloxane copolymer, both ends dimethyl hydrogen diene siloxy group methylhydrogenpolysiloxane blocked diene-dimethylsiloxane-diphenyl siloxane _{copolymer, (CH} 3) 2 _{HSiO 1/2} units and _{(CH 3) 3} SiO _{1 / 2} unit and SiO _4/2 unit copolymer, (CH ₃ ) ₂ HSiO _1/2 unit and SiO _4/2 unit copolymer, (CH ₃ ) ₂ HSiO _1/2 unit and SiO _Examples thereof include a copolymer composed of _4/2 units and (C ₆ H ₅ ) ₃ SiO _1/2 units.

In the addition-curable silicone rubber composition, the proportion of the organopolysiloxane and the organohydropolyene polysiloxane is such that the aliphatic unsaturated hydrocarbon group in the organopolysiloxane and the hydrogen atom in the organohydropolyene polysiloxane are mixed. The molar ratio is preferably 1:10 to 10: 1, and more preferably 1: 3 to 3: 1.

The platinum-based catalyst is a component having a function of initiating an addition reaction between the organopolysiloxane and the organohydropolyene polysiloxane. For example, platinum, platinum chloride, chloroplatinic acid, a vinylsiloxane complex thereof, Examples include platinum group metal compounds such as alcohol-modified solutions; rhodium compounds and palladium compounds. The platinum catalyst content is preferably 0.1 to 1000 ppm, more preferably 1 to 500 ppm, based on the organopolysiloxane.

The addition-curable silicone rubber composition may contain reinforcing silica. This is a filler blended to enhance strength characteristics, and examples thereof include fumed silica, precipitated silica, and fused silica. The particle diameter is preferably 20 μm or less. The reinforcing silica may be one that has been previously surface-treated with organosilane, organosiloxane, organosilazane, or the like, or may be one that has been reacted with the treatment agent in-process. The content of the reinforcing silica is preferably 5 to 200 parts by mass with respect to 100 parts by mass of the organopolysiloxane.

The addition-curable silicone rubber composition may also contain a known reaction control agent such as an acetylene compound, a phosphorus compound, a nitrile compound, a carboxylate, a tin compound, a mercury compound, or a sulfur compound.
As a commercial item of the said addition curable silicone rubber composition, TSE3032 (made by GE Toshiba Silicone), KE103 (made by Shin-Etsu Polymer) etc. can be mentioned, for example.

In the step (I), for example, a constituent material of a molded body of silicone rubber such as the above addition curable silicone rubber composition is poured into a mold of a centrifugal molding machine preheated to 30 to 50 ° C., and 120 to 180 A silicone rubber molded body can be produced by curing for a minute.

The thickness of the silicone rubber molded body (silicone rubber layer) formed in the step (I) is preferably 0.5 to 3 mm. If it is less than 0.5 mm, the thickness of the silicone rubber layer is too thin to have strength, and there is a possibility that all cannot be peeled cleanly when peeled from the mold. If it exceeds 3 mm, the heat of the mold cannot be effectively transferred, and the properties of the formed elastic rubber member material layer may be adversely affected.

In the method for manufacturing the cleaning blade for an electrophotographic apparatus, after the step (I), a molded body constituting the edge layer of the elastic rubber member is manufactured on the silicone rubber molded body obtained in the step (I). A process is performed (process (II)). Moreover, after the said process (II), the process of manufacturing the molded object which comprises layers other than an edge layer on the molded object which comprises the edge layer obtained by process (II) is performed (process (III)). ). By performing the steps (II) and (III) by a conventionally known centrifugal molding technique, an elastic rubber member having a multi-layer structure having an edge layer and a layer other than the edge layer can be manufactured satisfactorily. The molded body constituting the layers other than the edge layer may be either one having only one layer or one having one or more other molded bodies in addition to the molded body. In addition, a smooth silicone rubber contact surface in the manufactured edge layer can be used as a use surface (a contact surface with a counterpart material), and excellent cleaning properties (particularly, low temperature and low humidity) can be obtained.

In the manufacturing method, the molded body constituting the layer other than the edge layer is the same as the material of the layer other than the edge layer described above. Moreover, as a molded object which comprises an edge layer, it is preferable to use the thing similar to the material of the edge layer mentioned above.

In the production method, the step (III) is a step of producing a molded body constituting the base layer of the elastic rubber member on the molded body constituting the edge layer obtained in the step (II). The molded body constituting the elastic rubber member is made of a material satisfying the characteristic that the hysteresis loss (B / A) of deflection and bending load is B / A <0.5 in the three-point bending test with the edge layer on the upper side. Is preferred. In this case, a cleaning blade having a two-layered elastic rubber member excellent in cleaning properties (particularly low temperature and low humidity) can be produced.

A conventionally known two-layer elastic rubber is manufactured by a centrifugal molding method in which a molded body constituting the edge layer is produced in the step (II) and then a molded body constituting the base layer is produced in the step (III). This can be done by a method for forming a member material layer. When producing the elastic rubber member in which the molded bodies constituting the edge layer and the base layer are both made of polyurethane, the step (II) and the step (III) can be performed using, for example, the following method.

In the step (II), the edge layer material is preheated and injected at 130 to 150 ° C. on the silicone rubber molded body in the mold of the centrifugal molding machine obtained in the step (I). And cured for 5 to 10 minutes. Next, in the step (III), after the curing reaction in the step (II), the base layer material is injected onto the cured edge layer and cured for 25 to 50 minutes. A cylindrical sheet body having a thickness of 1 to 3 mm can be obtained by peeling the sheet body of the elastic rubber member having a two-layer structure from the molded body of silicone rubber and taking it out of the mold. An elastic rubber member can be obtained by cutting this into a strip shape having a width of 8 to 20 mm and a length of 220 to 500 mm.

In the above production method, the molded body constituting the edge layer and the base layer can be obtained by a prepolymer method, a one-shot method or the like.
In the case of using the prepolymer method, a polyol and isocyanate subjected to dehydration treatment are mixed and reacted at a temperature of 50 to 80 ° C. for 10 to 600 minutes. A cured edge layer and base layer can be obtained by a method of injecting and curing. When using the one-shot method, weigh the polyol and cross-linking agent that have been dehydrated, add polyisocyanate to them, weigh and mix them, inject them into the mold, and cure them, etc. A cured edge layer and base layer can be obtained.

In the above production method, after obtaining an elastic rubber member having a multilayer structure, step (IV) is usually performed in which the obtained elastic rubber member and the support member are bonded. The step (IV) can be performed by a conventionally known method, and can be performed by, for example, bonding using the above-described adhesive. In the step (IV), the support member is the same as described above. Thereby, the cleaning blade etc. shown in FIG. 1 can be manufactured.

Since the cleaning blade for an electrophotographic apparatus of the present invention has the above-described configuration, it has excellent cleaning properties even when a polymerization toner having a spherical shape (true spherical shape or irregular shape) and a small particle size is used. (Especially under low temperature and low humidity).

EXAMPLES Hereinafter, although an Example is hung up and demonstrated in more detail, this invention is not limited only to these Examples. In the examples, “parts” and “%” mean “parts by mass” and “% by mass” unless otherwise specified.

Examples 1 to 7 and Comparative Examples 1 to 2 Manufacturing of a cleaning blade (elastic rubber member having a two-layer structure including an edge layer and a base layer)
(Formation of silicone rubber layer)
A molding die drum of a known centrifugal molding machine (inner diameter: 700 mm, depth: 500 mm, runout accuracy at room temperature: 0.06 mm, rotation speed during molding: 800 rpm, rough surface state: Ra = 0.30) at 40 ° C. Of the addition-curable silicone rubber composition “TSE3032 (A)” (main agent, manufactured by GE Toshiba Silicones) and “TSE3032 (B)” (curing agent), which are cured by addition reaction as a silicone rubber material. The liquid (compounding mass ratio 10: 1) was poured into the molding die drum and heat-cured for 120 minutes to form a silicone rubber layer. The obtained silicone rubber layer had a uniform mirror surface on the air side surface and a thickness of 0.7 mm.

(Formation of elastic rubber member material layer)
The edge layer material was poured onto a silicone rubber layer in a mold of a centrifugal molding machine preheated to 140 ° C. and cured for 10 minutes. After the curing reaction, the base layer material was poured onto the cured edge layer and cured for 30 minutes. After the curing reaction, only a sheet of the elastic rubber member having a two-layer structure was taken out from the mold, whereby a cylindrical two-layer structure sheet having a thickness of 2.00 mm could be obtained. An elastic rubber member could be obtained by cutting this into a strip shape having a width of 12 mm and a length of 330 mm. Further, the surface state (silicone rubber contact surface) of the edge layer of the elastic rubber member was a mirror surface state, and no defects were found.

Further, the obtained elastic rubber member was bonded to a support member made of plated steel using a polyurethane hot melt adhesive to obtain a cleaning blade.

Used edge layer material, base layer material, edge layer thickness (a), base layer thickness (b), a / (a + b), A, B in the three-point bending test with the edge layer facing upward, The hysteresis loss (B / A) is as shown in Tables 1-2. A, B, and B / A are values measured by the method described above.
Further, the polyurethanes in Tables 1 and 2 have the formulations shown in Table 3.

In the production of the cleaning blade, a method of injecting each polyurethane material (polyurethanes A to F) into the mold as an edge layer material and a base layer material is as follows.
The polyol and isocyanate subjected to the dehydration treatment were mixed and reacted at a temperature of 70 ° C. for 240 minutes, and then a crosslinking agent was added to the prepolymer, which was then injected (prepolymer method).
The dehydrated polyol and the cross-linking agent are weighed, and polyisocyanate is further added thereto, weighed and mixed, and poured into a mold (one-shot method).

(Print test)
The cleaning blades obtained in Examples and Comparative Examples were mounted on a commercially available plain paper copying machine (using an organic photoreceptor, speed 10 sheets / minute), and a printing test was performed. The test was performed under the conditions of (1) a temperature of 23 ° C. and a humidity of 50%, and (2) a temperature of 10 ° C. and a humidity of 15%. The print test was completed after every 1000 sheets to check whether or not toner slipped out, and when a streak caused by toner slipping was found in the printed matter, the number of printed sheets was recorded. If no streak occurred even after printing 100,000 sheets, the test was terminated. The occurrence of toner slipping and reversal turning during the test was evaluated. The results are shown in Table 1.

From the table, it was found that the cleaning blade obtained in the example did not slip through the toner under normal temperature and humidity. Further, it had a cleaning property that had no practical problem even under low temperature and low humidity. On the other hand, the performance of the comparative example was inferior.

The cleaning blade for an electrophotographic apparatus of the present invention can be suitably used for an electrostatic electrophotographic copying machine using plain paper as recording paper.

FIG. 3 is a schematic view showing a cleaning blade for an electrophotographic apparatus of the present invention. It is an example of the relationship curve of the bending (d) and bending load (F) of a three-point bending test.

Explanation of symbols

11 Elastic rubber member 12 Support member 13 Adhesive layer 14 Image carrier (mating material)
21 Edge layer 22 Base layer 23 Edge layer side surface 24 Pressing direction of the pressure wedge (when the edge layer side is on the upper side)

Claims (5)

A cleaning blade for an electrophotographic apparatus having an elastic rubber member and a support member,
The elastic rubber member has a multilayer structure of two or more layers having an edge layer and a layer other than the edge layer, and
In the three-point bending test with the edge layer on the upper side, the hysteresis loss (B / A) of deflection and bending load is expressed by the following formula (1);
0.2 ≦ B / A ≦ 0.4 (1)
A cleaning blade for an electrophotographic apparatus, comprising a material satisfying the above characteristics. The elastic rubber member has a two-layer structure including an edge layer and a base layer, and
In the three-point bending test with the edge layer on the upper side, the hysteresis loss (B / A) of deflection and bending load is expressed by the following formula (1);
0.2 ≦ B / A ≦ 0.4 (1)
The cleaning blade for an electrophotographic apparatus according to claim 1, wherein the cleaning blade is made of a material satisfying the characteristics of The edge layer is made of polyurethane containing polycaprolactone polyol and / or polyester polyol as a polyol component, and at least one layer other than the edge layer is made of polyurethane containing polycaprolactone polyol and / or polyester polyol as a polyol component. 3. A cleaning blade for an electrophotographic apparatus according to 1 or 2. The method for producing a cleaning blade for an electrophotographic apparatus according to claim 1, 2 or 3, wherein a centrifugal molding method is used,
A step (I) of producing a molded product of silicone rubber inside the mold; and
Step (II) for producing a molded body constituting the edge layer of the elastic rubber member on the silicone rubber molded body obtained in the step (I);
A step (III) of producing a molded body constituting a layer other than the edge layer of the elastic rubber member on the molded body constituting the edge layer obtained in the step (II),
In the molded body constituting the obtained elastic rubber member, in a three-point bending test with the edge layer on the upper side, the hysteresis loss (B / A) of deflection and bending load is expressed by the following formula (1);
0.2 ≦ B / A ≦ 0.4 (1)
A method for producing a cleaning blade for an electrophotographic apparatus, characterized by comprising a material satisfying the above characteristics. Silicone rubber molded body includes organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups bonded to silicon atoms, organohydrodiene polysiloxane having at least two hydrogen atoms bonded to silicon atoms, and platinum-based 5. The method for producing a cleaning blade for an electrophotographic apparatus according to claim 4, wherein the method is obtained from an addition-curable silicone rubber composition containing a catalyst.

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