JP2008070634A - Cleaning blade for electrophotographic apparatus and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning blade for an electrophotographic apparatus having a small coefficient of friction and excellent cleaning performance and a method for manufacturing the same. <P>SOLUTION: The cleaning blade for an electrophotographic apparatus includes an elastic rubber member, a support member and an adhesive layer, wherein the elastic rubber member has a two-layer structure comprising a cleaning layer not joined to the support member and a base layer joined to the support member by way of the adhesive layer. The cleaning layer comprises a polyurethane having a JIS A hardness at 23°C of 91-99° and the base layer comprises a polyurethane having a JIS A hardness at 23°C of 60-80°. The ratio between the thickness (a) of the cleaning layer and the sum of the thickness (a) of the cleaning layer and the thickness (b) of the base layer (a+b), (a/(a+b)) is ≤1/3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

According to an electrostatic electrophotographic copying machine using plain paper as a recording paper, generally, an electrostatic charge is given to the surface of the image carrier by discharge, and an image is exposed thereon to form an electrostatic latent image. Then, the charged toner is attached to the electrostatic latent image and developed, and the toner image is transferred to the recording paper. Finally, the recording paper on which the toner image is transferred is heated and pressurized to fix the toner on the recording paper. Make a copy.

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. The cleaning blade for an electrophotographic apparatus is usually formed of 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.

Such a cleaning blade for an electrophotographic apparatus is reduced in size and price, prevents a reverse turning abnormality that is a potential problem of the cleaning blade, simplifies the drive system, and prevents the blade from adhering to the surface of the image carrier. There is a demand for etc. In order to satisfy such a requirement, it is considered effective to reduce the friction coefficient between the blade and the surface of the image carrier. Therefore, it is desired to provide a cleaning blade having a small friction coefficient. Furthermore, it is also desired that a cleaning blade having the above-described performance and excellent cleaning properties can be manufactured with high productivity.

Patent Document 1 discloses a material layer in which a cleaning edge side layer made of a urethane resin having a high hardness of 90 degrees or more and a layer made of a urethane resin having a low degree of JIS-A hardness of 80 degrees or less are laminated. A cleaning blade is disclosed, which is intended to improve cleaning properties and prevent blade squealing and blade swell. However, since the cleaning property may not be satisfactory, further improvement is desired. Further, the coefficient of friction is not considered in detail.

Patent Documents 2 to 3 describe an elastic rubber member having a two-layer structure and a support composed of an edge layer made of polyurethane having a JIS-A hardness of 70 to 85 and a base layer made of polyurethane having a JIS-A hardness of 65 to 70. A cleaning blade for an electrophotographic apparatus having a member is disclosed, which is intended to improve the scraping property and noise prevention property. However, since the cleaning property may not be sufficiently satisfied, further improvement is desired. In addition, the hardness and friction coefficient of the edge layer are not examined in detail.

Patent Documents 4 to 5 disclose cleaning blades in which the side of the blade member in contact with the image carrier is a high hardness layer and the other side is a low hardness layer, but performance such as cleaning properties is satisfactory. There are cases where it is not possible. Patent Document 6 discloses a cleaning blade for an electrophotographic apparatus having a blade member having a two-layer structure, and this blade member has a lower hardness in a layer contacting the image carrier than a layer on the other surface side. Is. For this reason, performance such as cleaning properties may not be satisfied.

Patent Document 7 discloses a blade member obtained by coating a part of the surface of the member with a resin or the like, and Patent Document 8 discloses a blade member obtained by impregnating a part of the member with other components. Has been. However, a blade member coated with such a resin or a blade member impregnated with other components has a structure different from a blade member having a two-layer structure. Also, there are cases where performance such as cleaning properties cannot be satisfied.
JP 2004-184462 A JP 2002-214989 A JP 2002-214990 A JP 63-226683 A JP-A-63-235977 JP-A-60-165682 Japanese Patent Laid-Open No. 9-127846 JP 2003-122222 A

An object of the present invention is to provide a cleaning blade for an electrophotographic apparatus having a small friction coefficient and an excellent cleaning property, and a method for manufacturing the same.

The present invention is a cleaning blade for an electrophotographic apparatus having an elastic rubber member, a support member, and an adhesive layer, wherein the elastic rubber member is not bonded to the support member, the cleaning layer, the support member, and the adhesive. The cleaning layer is made of polyurethane having a JIS A hardness of 91 ° to 99 ° at 23 ° C., and the base layer is composed of a base layer joined through layers. It is made of polyurethane having a JIS A hardness of 60 ° to 80 ° at 23 ° C., and is the sum of the thickness (a) of the cleaning layer, the thickness (a) of the cleaning layer, and the thickness (b) of the base layer. The ratio (a / (a + b)) to (a + b) is 1/3 or less.

The cleaning layer is preferably made of polyurethane having a JIS A hardness of 92 ° to 98 ° at 23 ° C.
The base layer is preferably made of polyurethane having a JIS A hardness of 62 ° to 77 ° at 23 ° C.

It is preferable that a urethane bond is formed between the cleaning layer and the base layer.
Both the cleaning layer and the polyurethane of the base layer preferably comprise polyester polyol as a polyol component.

Both the cleaning layer and the polyurethane of the base layer preferably contain polycaprolactone polyol, polyethylene adipate, polybutylene adipate or polyethylene butylene adipate as a polyol component.

A step (1) of manufacturing an elastic rubber member having a two-layer structure of a cleaning layer and a base layer by using a centrifugal molding method, and the elastic rubber member obtained in the above step (1) and the support member are bonded. Including the step (2), the cleaning layer is made of polyurethane having a JIS A hardness of 91 ° to 99 ° at 23 ° C., and the base layer has a JIS A hardness of 60 ° to 80 at 23 ° C. The ratio of the thickness (a) of the cleaning layer to the sum (a + b) of the thickness (a) of the cleaning layer and the thickness (b) of the base layer (a / (a + b)) ) Is also a method of manufacturing a cleaning blade for an electrophotographic apparatus, characterized in that it is 1/3 or less.
Hereinafter, the present invention will be described in detail.

The cleaning blade for an electrophotographic apparatus of the present invention (hereinafter also simply referred to as “cleaning blade”) comprises a cleaning layer that is not bonded to a support member and a base layer that is bonded to the support member via an adhesive layer. It has a layered elastic rubber member. The cleaning layer is made of polyurethane having a JIS A hardness of 91 ° to 99 ° at 23 ° C., and the base layer is made of polyurethane having a JIS A hardness of 23 ° C. to 60 ° to 80 °. Is. Furthermore, the ratio (a / (a + b)) of the thickness (a) of the cleaning layer to the sum (a + b) of the thickness (a) of the cleaning layer and the thickness (b) of the base layer is 1/3 or less. It is.

Since the cleaning blade has the configuration described above, when it is used, the friction coefficient between the elastic rubber member and the surface of the image carrier can be reduced. Therefore, it is possible to satisfy the demands such as downsizing and cost reduction, prevention of reverse turning abnormality, simplification of the drive system, prevention of adhesion of the blade to the surface of the image carrier.

When the cleaning blade is used, the contact pressure of the edge portion with respect to the surface of the image carrier is usually within a proper range of 30 to 70 g / cm. If it is less than the lower limit, the toner blocking effect is too low and toner slips out, resulting in poor cleaning.If the upper limit is exceeded, the edge of the image carrier may be damaged or scraped off. This is because the performance of the image carrier is lowered and image fogging occurs. For example, in the case of a blade having a single-layer, high-hardness elastic rubber member, the bending spring constant of the blade is very high, and in order to suppress variations in the contact pressure of the edge portion within an appropriate range, However, since the present invention has the above-described configuration, it produces a cleaning blade having a contact pressure within the appropriate range. It can be manufactured with good performance.

The cleaning blade of the present invention can adjust the contact pressure of the edge with the surface of the image bearing member within an appropriate range when in use, so that a high toner damming effect is exhibited and toner can be prevented from slipping through. As a result, excellent cleaning properties are exhibited. Such excellent cleaning properties are also exhibited when a polymerization method toner having a spherical shape (true spherical shape or irregular shape) and a small particle size is used.

The cleaning blade of the present invention can be used favorably in an apparatus using a polymerization toner having a small particle diameter of 6 to 8 μm. Further, even an apparatus using a polymerization toner having a weight average particle diameter of 5 to 6 μm can be used satisfactorily.

It is assumed that excellent cleaning performance is exhibited when the cleaning blade of the present invention is used, because the following functions and functions are also involved.
In the cleaning blade of the present invention, since the cleaning layer of the elastic rubber member is made of polyurethane having a specific hardness (91 ° to 99 °), the edge portion in use is hardened. For this reason, if the pressing load does not change, the deformation of the edge portion is reduced, the nip area is reduced, and the load per nip area is increased. As a result, it is presumed that the toner can be prevented from slipping out and the cleaning property can be improved.

The cleaning blade has an elastic rubber member, a support member, and an adhesive layer.
The elastic rubber member scrapes off toner, external additives, and the like on the surface of the image carrier when the cleaning blade is used. The cleaning layer is not bonded to the support member, and the support member and the adhesive layer. It has a two-layer structure consisting of a base layer joined through a gap. Here, joining means being in contact with each other. In the present invention, as shown in FIG. 1 to be described later, the cleaning layer is not in contact with (not joined to) the support member, and the base layer is in contact with the support member via the adhesive layer. (Joined).

In the elastic rubber member, the cleaning layer and the base layer have a two-layer structure made of polyurethane having a specific hardness. As a result, the coefficient of friction between the elastic rubber member and the surface of the image carrier can be reduced, and excellent cleaning properties can be exhibited. In addition, the cleaning blade can be manufactured with high productivity.

As shown in FIG. 1 described later, the cleaning layer is a layer that constitutes an elastic rubber member and is not joined to the support member. When the cleaning blade is used, the friction coefficient between the elastic rubber member and the surface of the image carrier can be reduced by bringing the edge portion of the cleaning layer with high hardness into contact with the image carrier, and the surface of the image carrier The toner, external additives, and the like can be scraped off satisfactorily.

The cleaning layer is made of polyurethane having a JIS A hardness of 91 ° to 99 ° at 23 ° C. By being within the above range, the coefficient of friction with the image carrier can be greatly reduced under the same contact pressure. This is presumably because the amount of deformation of the edge portion during use decreases, and the contact area with the image carrier decreases. Therefore, performances such as downsizing and cost reduction, prevention of reversal turning abnormality, simplification of the drive system, and prevention of adhesion of the blade to the surface of the image carrier can be exhibited. In addition, a cleaning blade that exhibits excellent cleaning properties can be manufactured with high productivity.

If the hardness of the cleaning layer is less than 91 °, the friction coefficient with the image bearing member may be increased or the cleaning property may be deteriorated under the same contact pressure. If it exceeds 99 °, it may be difficult to form an edge portion by cutting. It is preferably 92 ° to 98 °, and more preferably 93 ° to 97 °.

The cleaning layer preferably has a rebound resilience at 23 ° C. of 25 to 60%. If it is less than 25%, the restoring speed of the edge portion elastically deformed following the surface of the image carrier is slow, and residual toner slips through when it is caught in the rotating image carrier, resulting in image defects such as streaks. May occur. If it exceeds 60%, the friction coefficient may increase. Further, there is a risk that abnormal noise (squeal) is likely to be generated at high temperatures when the electrophotographic apparatus is started and stopped, and continuously during operation. More preferably, it is 35 to 55%.

The cleaning layer preferably has a 100% modulus in the range of 15.3 to 35.7 MPa. Within the above range, the coefficient of friction can be reduced, and excellent cleaning properties can be obtained. More preferably, it is in the range of 17.5 to 22.6 MPa.

As shown in FIG. 1 described later, the base layer is a layer that constitutes an elastic rubber member, and is a layer that is bonded to the support member via an adhesive layer. When the cleaning blade is used, the contact pressure between the edge portion and the image carrier can be adjusted by using an elastic rubber member having a low hardness base layer.

The base layer is made of polyurethane having a JIS A hardness of 60 ° to 80 ° at 23 ° C. Thereby, it can prevent that the bending spring constant as an elastic rubber member becomes large too much, and can make a contact pressure into an appropriate range. In addition, a cleaning blade that exhibits excellent cleaning properties can be manufactured with high productivity. It is preferably 62 ° to 77 °, more preferably 62 ° to 70 °.

The base layer preferably has a rebound resilience at 23 ° C. of 5 to 50%. If it is less than 5%, the rubber elasticity (elastomer property) becomes poor, the force for pressing the image bearing member becomes too weak, and the residual toner may slip through. If it exceeds 50%, the friction coefficient may increase. Further, there is a risk that abnormal noise (squeal) is likely to be generated at high temperatures when the electrophotographic apparatus is started and stopped, and continuously during operation. More preferably, it is 5 to 35%.

In the present specification, the JIS A hardness is a value measured by a spring type A hardness tester according to JIS K 7312, and the rebound resilience is a rebound resilience test according to JIS K 7312. Accordingly, the value is measured. The 100% modulus is a value measured according to JIS K 6301 (dumbbell-shaped No. 3 test piece). In the present invention, the cleaning layer and the base layer having the above-described hardness, impact resilience, and 100% modulus can be obtained by appropriately selecting the material of the polyurethane constituting the cleaning layer and the base layer.

In the elastic rubber member, the ratio (a / (a + b)) of the thickness (a) of the cleaning layer to the sum (a + b) of the thickness (a) of the cleaning layer and the thickness (b) of the base layer is: 1/3 or less. That is, the elastic rubber member in the present invention has a relatively small thickness (a) of the cleaning layer with respect to the entire elastic rubber member. Since the elastic rubber member having such a configuration is provided, the friction coefficient between the elastic rubber member and the surface of the image carrier can be reduced. Further, the contact pressure can be within an appropriate range, and the cleaning property can be improved.

When the ratio (a / (a + b)) exceeds 1/3, there is a possibility that residual toner, external additives, and the like on the surface of the image bearing member may slip through and the cleaning property may be deteriorated. In addition, the friction coefficient may increase. The ratio (a / (a + b)) is preferably 1/3 to 1/9, and more preferably 1/4 to 1/9.

The thickness (a) of the cleaning layer is preferably 0.1 to 0.8 mm. By being within the above range, it is possible to prevent slipping of residual toner, external additives and the like on the surface of the image bearing member, and to improve cleaning properties. In addition, the friction coefficient can be reduced. More preferably, it is 0.5 to 0.7 mm.

Since both the cleaning layer and the base layer are made of polyurethane having a specific hardness, it is possible to effectively prevent slipping of residual toner, external additives, and the like on the surface of the image bearing member, thereby improving cleaning properties. it can. In addition, the friction coefficient can be reduced. Furthermore, the cleaning blade can be manufactured with high productivity. Examples of the polyurethane include those obtained by reacting a polyol, polyisocyanate, and, if necessary, a crosslinking agent.

It does not specifically limit as said polyol, For example, a polyester polyol, polyether polyol, etc. can be mentioned. These may be used alone or in combination of two or more. The polyurethanes in both layers are preferably those having polyester polyol as a polyol component.

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 dicarboxylic acid is preferably an aliphatic dicarboxylic acid and more preferably adipic acid from the viewpoint that the coefficient of friction can be reduced and the cleaning property can be improved. The glycol is preferably an aliphatic glycol, and more preferably ethylene glycol, 1,4-butanediol, ethylene glycol and 1,4-butanediol in combination (random copolymerization thereof).

Examples of the polyester polyol include polycaprolactone polyol.
As the polycaprolactone polyol, those obtained by ring-opening addition of ε-caprolactone using a low molecular weight glycol as an initiator in the presence of a catalyst are preferably used. The low molecular weight glycol is preferably a divalent alcohol such as ethylene glycol, propylene glycol, 1,3-butylene glycol or neopentyl glycol, or a trivalent alcohol such as trimethylene glycol or glycerin. Especially, it is more preferable to use ethylene glycol from the point which can reduce a friction coefficient and the point which can improve cleaning property. The catalyst uses organic titanium compounds such as tetrabutyl titanate, tetrapropyl titanate, tetraethyl titanate, tin compounds such as tin octylate, dibutyltin oxide, dibutyltin laurate, stannous chloride, stannous bromide, etc. It is preferable to do. In addition to the above ε-caprolactone, other cyclic lactones such as trimethylcaprolactone and valerolactone may be partially mixed.

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

As the polyol constituting the polyurethane of the cleaning layer and the base layer, among those described above, both the polycaprolactone polyol, the polyethylene adipate, the point that the friction coefficient can be lowered, and the cleaning property can be improved. It is particularly preferred to use polybutylene adipate or polyethylene butylene adipate, and it is most preferred to use polycaprolactone polyols together.

The polyol preferably has a number average molecular weight of 1000 to 3000. By using a polyol within the above range, it is possible to effectively prevent slipping of residual toner, external additives and the like on the surface of the image bearing member, and improve cleaning properties. In addition, the friction coefficient can be reduced. The number average molecular weight is a value determined in the GPC method using styrene polymer as a standard.

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 preferable from the viewpoint that the friction coefficient can be lowered and the cleaning property can be improved.

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 polyisocyanates, MDI and urethane-modified MDI are more preferable, and MDI is particularly preferable from the viewpoint that the coefficient of friction can be reduced and the cleaning property can be improved.

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 them, ethylene glycol, 1,4-butanediol, trimethylolpropane, N, N-bis (2-hydroxypropyl) aniline can be used because the friction coefficient can be lowered and the cleaning property can be improved. Is preferred.

The polyurethane can be produced by a known method using the above raw materials. For example, a catalyst is used in an appropriate organic solvent as necessary, and the equivalent ratio of each raw material is NCO / OH = 0.9 to It can be produced by adjusting to 1.1 and reacting, or by 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 centrifugal molding from the viewpoint that an elastic rubber member having a two-layer structure can be obtained satisfactorily and a blade having excellent cleaning properties and a reduced friction coefficient can be suitably obtained.

In the elastic rubber member of the cleaning blade, it is preferable that a urethane bond is formed between the cleaning layer and the base layer. In this case, a strong bonding force (adhesion) can be obtained between the cleaning layer and the base. For this reason, it is not necessary to bond the cleaning layer and the base layer using an adhesive. The elastic rubber member in which the urethane bond is formed between the two layers can be satisfactorily manufactured by using a centrifugal molding method. Centrifugal molding can be performed by a conventionally known method, for example, the method described in the production method described later.

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 adhesive layer is a layer having a function of bonding the support member and the elastic rubber member. 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.

The electrophotographic apparatus cleaning blade of the present invention has, for example, the configuration shown in FIG. The cleaning blade shown in FIG. 1 has an elastic rubber member 1, a support member 2, and an adhesive layer 3. The elastic rubber member 1 includes a high hardness cleaning layer 4 and a low hardness base layer. 5 having a two-layer structure. The edge portion 6 of the high hardness cleaning layer 4 is a portion that is brought into contact with an image carrier (not shown) when the cleaning blade is used. When the cleaning blade having the structure as shown in FIG. 1 is used, the friction coefficient between the elastic rubber member 2 and the surface of the image carrier can be reduced, and excellent cleaning properties can be exhibited. Moreover, since it is the said structure, the cleaning blade used as the contact pressure in an appropriate range can be manufactured with sufficient productivity.

The cleaning blade of the present invention preferably has a dynamic friction coefficient of 0.40 to 0.70 against a Haydon type versus OPC film (image bearing member) at a friction speed of 1500 mm / min. Although it is preferable that the Haydon formula vs. glass dynamic friction coefficient is low, in the case of polyurethane, the practical lower limit is 0.40. If it exceeds 0.70, the sliding surface of the blade tends to wear out, the driving torque of the photosensitive member increases, and the rotation tends to become unstable. More preferably 0.45 to 0.70

As shown in FIG. 2, the Haydon type vs. OPC film dynamic friction coefficient was measured using a Haydon type surface property tester in an environment of 20 to 25 ° C. and a relative humidity of 40 to 55%. The initial peak resistance when the elastic rubber member is pressed against the mirror surface of the OPC film 8 at an angle of 25 ° with a load of 0.98 N at a position 5 mm inward from the blade tip edge and the OPC film surface is moved at 1500 mm / min. The sliding resistance F (N) at the time of stable sliding, excluding, is a value obtained by detecting the load cell with a load cell and calculating and averaging the recording chart with an analyzer.

The present invention is also a method of manufacturing a cleaning blade for an electrophotographic apparatus described below. Thereby, the cleaning blade of this invention mentioned above can be manufactured suitably.
The method for producing a cleaning blade for an electrophotographic apparatus according to the present invention comprises a step (1) of producing an elastic rubber member having a two-layer structure of a cleaning layer and a base layer using a centrifugal molding method, and the above step (1). It is a method including the process (2) which adhere | attaches the elastic rubber member and support member which were obtained by this. In the above production method, the cleaning layer is made of polyurethane having a JIS A hardness of 91 ° to 99 ° at 23 ° C., and the base layer has a JIS A hardness of 60 ° to 80 at 23 ° C. The ratio of the thickness (a) of the cleaning layer to the sum (a + b) of the thickness (a) of the cleaning layer and the thickness (b) of the base layer (a / (a + b)) ) Is 1/3 or less. In the step (1), by producing an elastic rubber member by centrifugal molding, it is possible to reduce the coefficient of friction and improve the cleaning property. In addition, a cleaning blade having a contact pressure within an appropriate range can be manufactured with high productivity.

In the above manufacturing method, the elastic rubber member having the two-layer structure of the cleaning layer and the base layer is the same as described above.
The centrifugal molding method for producing the elastic rubber member in the step (1) can be performed by a conventionally known method, for example, the method shown below.

First, using a cleaning layer material, a dehydrated polyol and isocyanate are mixed, and a prepolymer obtained by reacting at a temperature of 50 to 140 ° C. for 10 to 300 minutes is added with a crosslinking agent or the like. Pour into a mold of a centrifugal molding machine preheated to ˜150 ° C. and cure for 2 to 10 minutes. After the curing reaction, the base layer material similarly pretreated is injected onto the obtained cleaning layer and cured for 30 to 90 minutes. After the curing reaction, a cylindrical two-layer structure sheet having a thickness of 1 to 3 mm can be obtained by taking out from 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 elastic rubber member obtained by such a centrifugal molding method, a urethane bond is formed between the cleaning layer and the base layer. In this case, since a strong bonding force (adhesion force) is generated between the two layers, a good cleaning blade can be manufactured without adhering the two layers with an adhesive or the like.

In the centrifugal molding method in the above step (1), the order in which the cleaning layer material and the base layer material of the centrifugal molding machine are charged can be reversed. When the surface roughness of the inner surface of the cylindrical mold of the centrifugal molding machine to be used is large, as described above, when the mold inner surface side of the centrifugal molding machine is used as the cleaning layer, the surface roughness of the mold is transferred to the surface of the cleaning layer. The edge precision of the cleaning blade is rough and deteriorates. Therefore, in such a case, an elastic rubber member with good edge accuracy can be manufactured by reversing the material charging sequence.

In the said manufacturing method, after performing the said process (1), the process (2) which adhere | attaches the elastic rubber member obtained by the said process (1) and a support member is performed. The step (2) can be performed by a conventionally known method, for example, by bonding using the above-described adhesive. The support member used in the step (2) is the same as described above.

Since the cleaning blade for an electrophotographic apparatus of the present invention has the above-described configuration, the friction coefficient between the elastic rubber member and the surface of the image carrier can be reduced. For this reason, it is possible to satisfy the demands such as downsizing and cost reduction, prevention of reversal turning abnormality, simplification of the drive system, prevention of adhesion of the blade to the surface of the image carrier. Further, the cleaning blade exhibits a high toner dampening effect and prevents the toner from slipping out, so that excellent cleaning properties are exhibited. Furthermore, in the present invention, a cleaning blade in which the contact pressure of the edge portion with the surface of the image carrier is within an appropriate range can be manufactured with high productivity.

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 6 and Comparative Examples 1 to 8 Production of cleaning blade First, using a cleaning layer material, a dehydrated polyol and isocyanate are mixed and reacted at a temperature of 70C for 240 minutes. A cross-linking agent was added to the prepolymer obtained and injected into a mold of a centrifugal molding machine preheated to 140 ° C. and cured for 10 minutes. After the curing reaction, the base layer material pretreated in the same manner was poured onto the cured cleaning layer and cured for 30 minutes. After the curing reaction, a cylindrical two-layer structure sheet having a thickness of 2.00 mm could be obtained by taking out from the mold. 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.
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.

Table 1 shows the cleaning layer material, base layer material, cleaning layer, base layer thickness (a), (b), a / (a + b), hardness (23 ° C.), rebound resilience, and permanent elongation used. As shown. Hardness of the cleaning layer and base layer, impact resilience, 100% modulus, values measured by the method described above. Permanent elongation is a value measured by the method described in Table 1.

The polyurethane in Table 1 has the composition shown in Table 2.
The characteristic values of the materials used are as follows.
Polyethylene adipate ester diol: number average molecular weight 2000
Polybutylene adipate ester diol: number average molecular weight 2000
Polycaprolactone polyol: number average molecular weight 2000

(Measurement of dynamic friction coefficient)
Using the obtained cleaning blade, the dynamic friction coefficient of Haydon type vs. OPC film at a friction speed of 1500 mm / min was measured using a Haydon type surface property tester (HEIDON-14DR type). In addition, the measurement of Haydon type | mold vs. OPC film dynamic friction coefficient was performed 5 times, the average value of 3 times except the maximum value and the minimum value was made into the measured value, and the result was shown in Table 1.

(Print test)
The cleaning blades obtained in the examples and comparative examples were mounted on a commercially available plain paper copying machine (using an organic photoreceptor, speed 10 sheets / min), and a printing test was performed (in the atmospheres of 23 ° C. and 10 ° C.). Went below). The print test was completed after every 100 sheets, and it was checked whether or not the toner slipped out, and when the streaks due to the toner slipping were found in the printed matter, the number of printed sheets was recorded. If no streak occurred even after printing 30000 sheets, the test was terminated. The results are shown in Table 1.

From Table 1, the cleaning blade obtained in the example showed a small value of the dynamic friction coefficient of the OPC film. For this reason, what is obtained in the embodiment satisfies the requirements such as downsizing and price reduction, prevention of reversal turning abnormality, simplification of the drive system, prevention of adhesion of the blade to the surface of the image carrier, and the like. I was able to expect. Moreover, what was obtained in the Example from the result of the printing test has excellent cleaning properties. On the other hand, what was obtained by the comparative example showed the value with a large dynamic friction coefficient. Also, the cleaning property 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.

It is an example of the schematic of the cleaning blade for electrophotographic apparatuses of this invention. It is the schematic diagram which showed the anti- OPC film (image carrier) dynamic friction coefficient measuring method using the Haydon type surface property tester.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Elastic rubber member 2 Support member 3 Adhesive layer 4 Cleaning layer 5 Base layer 6 Edge part 7 Sample (cleaning blade)
8 OPC film (image carrier)

Claims (7)

An electrophotographic apparatus cleaning blade having an elastic rubber member, a support member, and an adhesive layer,
The elastic rubber member has a two-layer structure including a cleaning layer that is not bonded to the support member and a base layer that is bonded to the support member via the adhesive layer,
The cleaning layer is made of polyurethane having a JIS A hardness of 91 ° to 99 ° at 23 ° C.,
The base layer is made of polyurethane having a JIS A hardness of 60 ° to 80 ° at 23 ° C.,
The ratio (a / (a + b)) of the thickness (a) of the cleaning layer to the sum (a + b) of the thickness (a) of the cleaning layer and the thickness (b) of the base layer is 1/3 or less. A cleaning blade for an electrophotographic apparatus. The cleaning blade for an electrophotographic apparatus according to claim 1, wherein the cleaning layer is made of polyurethane having a JIS A hardness of 92 ° to 98 ° at 23 ° C. The cleaning blade for an electrophotographic apparatus according to claim 1 or 2, wherein the base layer is made of polyurethane having a JIS A hardness of 62 ° to 77 ° at 23 ° C. 4. The cleaning blade for an electrophotographic apparatus according to claim 1, wherein a urethane bond is formed between the cleaning layer and the base layer. 5. The cleaning blade for an electrophotographic apparatus according to claim 1, wherein both of the polyurethane of the cleaning layer and the base layer contain polyester polyol as a polyol component. 5. The cleaning blade for an electrophotographic apparatus according to claim 1, wherein the polyurethane of the cleaning layer and the base layer contains polycaprolactone polyol, polyethylene adipate, polybutylene adipate or polyethylene butylene adipate as a polyol component. A step (1) of producing an elastic rubber member having a two-layer structure of a cleaning layer and a base layer by using a centrifugal molding method, and the elastic rubber member obtained in the step (1) and the support member are bonded. Including step (2),
The cleaning layer is made of polyurethane having a JIS A hardness of 91 ° to 99 ° at 23 ° C.,
The base layer is made of polyurethane having a JIS A hardness of 60 ° to 80 ° at 23 ° C.,
The ratio (a / (a + b)) of the thickness (a) of the cleaning layer to the sum (a + b) of the thickness (a) of the cleaning layer and the thickness (b) of the base layer is 1/3 or less. A method of manufacturing a cleaning blade for an electrophotographic apparatus.

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