JP2008262022A - Blade for electrophotographic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blade for an electrophotographic device the service period of which is made longer. <P>SOLUTION: The blade for the electrophotographic device is equipped with an elastic member whose surface, at least, is formed of a polyurethane elastic body containing a filler, and besides the filler is dispersed in the polyurethane elastic body, in such a state that maximum particle size becomes 100 nm or smaller. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a blade for an electrophotographic apparatus.

Conventionally, members such as developing blades, cleaning blades, developing rollers, intermediate transfer rollers, and belts such as toothed belts for driving these rollers are used in electrophotographic apparatuses. It has been.
The blade for an electrophotographic apparatus usually uses a plate-like elastic member, and is used in a state where the surface of the plate-like elastic member is in contact with the outer peripheral surface of the photoreceptor or roller.

For example, the cleaning blade is disposed in the electrophotographic apparatus in contact with the photoconductor, and the plate-like elastic member is rotated to remove unnecessary toner adhering to the surface of the photoconductor when the electrophotographic apparatus is in operation. It is used in sliding contact with the photoreceptor.
The developing blade is placed in contact with the developing roller and arranged in the electrophotographic apparatus. When the electrophotographic apparatus is operated, the plate-like elastic member is used in sliding contact with the rotating developing roller.

Each of the plate-like elastic members used for these electrophotographic apparatus blades is required to have a suitable hardness, and a resin composition based on a polyurethane resin is used.
For example, Patent Document 1 describes that a polyurethane resin composition containing a specific polyol and isocyanate and a polyurethane elastic body formed from the polyurethane resin composition are used for a cleaning blade.
In addition, the polyurethane elastic body used in the blade for electrophotographic apparatus may be formed of a polyurethane resin composition containing a filler such as inorganic particles or organic particles. For example, Patent Document 2 discloses an average particle size. It is described that an elastic member of a blade is formed with a polyurethane resin composition containing a filler of 100 μm or less.

By the way, in general, when an elastic member is repeatedly subjected to deformation such as bending or stretching, there is a risk of causing a crack such as a crack, and the elastic member in an application to which such deformation is applied should have a long service life. There is a demand for improvement in mechanical strength such as tear strength.
However, for example, if an attempt is made to improve the mechanical strength of the elastic member by dispersing a filler such as a filler in the elastic body, the hardness is usually improved at the same time. It is difficult to improve the strength of the elastic member while maintaining it.
For this reason, the blade for an electrophotographic apparatus has a problem that it is difficult to make the service life longer than that of the conventional blade.

Japanese Patent Laid-Open No. 9-212059 JP 2006-343411 A

  In view of the above problems, an object of the present invention is to provide a blade for an electrophotographic apparatus capable of extending the service life.

  The present inventors have found that by including a filler in a predetermined state in the polyurethane elastic body, it is possible to improve mechanical strength such as tear strength while suppressing an increase in hardness, and completed the present invention. It is.

  In order to solve the above problems, the present invention is provided with an elastic member having at least a surface formed of a polyurethane elastic body containing a filler, and the filler has a maximum particle size of 100 nm or less in the polyurethane elastic body. Disclosed is a blade for an electrophotographic apparatus, characterized in that the blade is dispersed in such a state.

“The filler is dispersed in a state where the maximum particle size is 100 nm or less” means that the filler having a primary particle size of 100 nm or less is dispersed in the state of primary particles in the polyurethane elastic body, or Even when a plurality of primary particles of the filler are aggregated and contained in the polyurethane elastic body in the form of aggregated particles, the size is 100 nm or less. In a state where the filler exceeds 100 nm in the polyurethane elastic body, It is intended not to be contained substantially.
In addition, “substantially free” means that the filler is dispersed in the polyurethane elastic body in the form of primary particles and aggregated particles, and the number of primary particles and aggregated particles exceeding 100 nm is 0.5%. Intended to be less than
Whether or not the filler is contained in the polyurethane elastic body in a state exceeding 100 nm, and the number thereof, for example, a number randomly selected on the surface of the polyurethane elastic body using a scanning Auger electron spectrometer. It can be confirmed by performing mapping with the element peculiar to this filler on the place.

The blade for an electrophotographic apparatus of the present invention includes an elastic member whose surface is formed of a polyurethane elastic body containing a filler.
Moreover, the polyurethane elastic body contains the filler in a dispersed state having a maximum particle size of 100 nm or less.
Therefore, it is possible to improve mechanical strength such as tear strength while suppressing an increase in the hardness of the polyurethane elastic body.
That is, the service life of the electrophotographic blade using the polyurethane elastic body can be extended.

First, a printing mechanism in the electrophotographic apparatus will be described with reference to FIG.
FIG. 1 is a schematic diagram showing a printing mechanism of an electrophotographic apparatus, and printing by the electrophotographic apparatus is performed through the steps of forming, developing, transferring, and fixing an electrostatic latent image using the printing mechanism 1. Is.
Reference numeral 10 in FIG. 1 denotes a photoconductor on which an electrostatic latent image is formed, developed, and transferred to a printing medium.
The photoreceptor 10 is formed in a cylindrical shape as a whole, and can be rotated by a driving device via a timing belt attached to a longitudinal end portion of the cylindrical shape. The surface is smooth to be used for image formation.

  Reference numeral 11 denotes a charging roller for applying an electric charge to the surface of the photoconductor 10. Reference numeral 12 denotes a surface of the photoconductor 10 charged by the charging roller 11, which is irradiated with a laser beam or the like. It is an exposure machine for forming an electrostatic latent image by eliminating charges.

Reference numeral 20 denotes a developing roller for causing the toner T to adhere to the portion where the charge of the photoconductor 10 disappears to visualize (develop) the electrostatic latent image. Reference numeral 22 denotes a sliding contact with the developing roller 20. A supply roller for supporting the toner T supplied to the photosensitive member 10 on the surface of the developing roller 20. The supply roller 22 thins and leveles the toner T supported on the surface of the developing roller 20 by the supply roller 22. The developing blade has a plate-like elastic member 21b that comes into contact with the surface of the developing roller 20 and a support member 21a for supporting the elastic member 21b.
A voltage is applied to both the developing roller 20 and the supply roller 22, and the voltage is such that the toner T can be attracted to the developing roller 20 side by passing between the developing roller 20 and the supply roller 22. Applied.
Although no voltage is applied to the developing blade 21, the elastic member 21 b is applied to the developing roller 20 in order to frictionally charge the toner T passing between the developing blade 21 and the developing roller 20. It is in contact with the electrophotographic apparatus.

  Reference numeral 30 denotes a transfer roller provided in the electrophotographic apparatus so that the print medium A can be sandwiched together with the photoconductor 10. The transfer roller 30 prints an image (toner) developed on the surface of the photoconductor 10. It is provided on the medium A so as to be transferred by electrostatic force.

  A fixing device 40 heats and presses the toner transferred onto the printing medium A by the transfer roller 30 and fixes the toner onto the printing medium A. The fixing device 40 sandwiches the printing medium A 2. Book fixing rollers 41a and 41b are provided.

  Reference numeral 50 denotes a case where the toner T remains on the surface of the photoconductor 10 after the transfer of the toner T from the surface of the photoconductor 10 to the printing medium A by the transfer roller 30 to remove the deposits on the surface of the photoconductor 10. A cleaning blade for cleaning the surface. The cleaning blade 50 includes a plate-like elastic member 50b that contacts the surface of the photoconductor 10 and a support member 50a for supporting the elastic member 50b. is doing.

Reference numeral 60 denotes a driving device for driving the photoconductor 10.
Reference numeral 61 denotes a timing belt for driving the photosensitive member 10 at a constant speed. As the timing belt 61, a toothed belt having irregularities formed on the inner peripheral surface is used.
62 is a timing pulley having an outer peripheral surface that can be fitted to the irregularities of the inner peripheral surface of the timing belt 61, and 63 is a driving motor for applying a driving force to the timing pulley 62 via a transmission gear G. is there.
The drive motor 63 is provided with a drive gear 63a fixed to the rotating shaft, and the timing pulley 62 is provided with a driven gear 62a fixed to the rotating shaft.
The transmission gear G is arranged in the driving device 60 in a state of being engaged with the driving gear 63a and the driven gear 62a.
64a and 64b have outer peripheral surfaces that can be fitted to the irregularities on the inner peripheral surface of the timing belt 61, and the outer peripheral surface of the timing belt 61 is partially formed on the outer peripheral surface on which the irregularities at the end of the photoreceptor 10 are formed. These are support pulleys arranged in the driving device 60 so that they can be supported in a state of being wound around.

Next, as an embodiment of the present invention, a cleaning blade 50 will be described as an example with reference to FIG. (FIG. 2 is a cross-sectional view schematically showing the structure of the cleaning blade 50.)
The cleaning blade 50 has a length corresponding to a smooth central region of the photoconductor 10, and a plate-like elastic member 50b formed so that a cross-sectional shape crossing the length direction is substantially rectangular, A support member 50a for supporting the elastic member 50b, and the support member 50a is formed of a plate material having substantially the same length as the elastic member 50b.
The elastic member 50 b is used with its surface, in particular, a corner (hereinafter referred to as “edge” or simply “edge”) of the rectangular cross section being in contact with the photosensitive member 10.
The surface side in contact with the photoreceptor 10 and the back side opposite to the surface side are formed of different materials, and a two-layer laminated structure is formed in the thickness direction.
More specifically, a layer (hereinafter also referred to as “edge layer 501”) disposed on the outermost surface side of the elastic member 50b is formed of a polyurethane resin composition containing a filler, and the back side of the edge layer 501 This layer (hereinafter also referred to as “base layer 502”) is formed of a polyurethane resin composition containing no filler.

Examples of the polyurethane resin composition used for forming the edge layer 501 of the elastic member 50b include those obtained by blending a thermosetting polyurethane resin component with a filler. A liquid that exhibits sufficient fluidity at a temperature of 70 ° C. is preferred.
When uncured, it is preferable that the liquid exhibits sufficient fluidity because it provides good workability when molding using a mold and the like, and air bleeding is also good. This is because the risk of generating defects such as bubbles in the formed edge layer 501 can be reduced.

In addition, in the cured polyurethane resin composition (hereinafter also referred to as “polyurethane elastic body”), it is preferable that the JIS A hardness at 23 ° C. can be set to about 65 to 72 °.
It is preferable that such hardness can be obtained at the time of curing. When the edge layer 501 is formed to have a JIS A hardness of less than 65 °, the nip width of the edge portion in contact with the photoconductor 10 is increased. This is because there is a possibility that the removal performance of the resin may be lowered, and if it exceeds 72 °, the wear resistance may be lowered.
In this respect, it is preferable that a polyurethane elastic body having a JIS A hardness of 65 to 70 ° can be formed after curing, and a polyurethane elastic body having a JIS A hardness of 65 to 68 ° can be formed after curing. More preferred.

  The “JIS A hardness” can be measured using a spring type A hardness tester according to JIS K 7312.

Moreover, as a polyurethane resin composition used for formation of this edge layer 501, what can form a polyurethane elastic body whose rebound resilience is 37 to 60% after hardening is preferable.
It is preferable that the rebound resilience be in such a range. If the edge layer 501 is formed to be less than 37% rebound resilience, the cleaning performance under low temperature and low humidity may be deteriorated. This is because the wear resistance may be reduced.
In this respect, it is preferable that a polyurethane elastic body having a rebound resilience of 37 to 50% after curing is preferable, and a polyurethane elastic body having a rebound resilience of 37 to 45% after curing is further preferable. .

  The “rebound resilience” can be measured using a rebound resilience tester according to JIS K 7312.

Moreover, as a polyurethane resin composition used for formation of this edge layer 501, what can form the polyurethane elastic body whose 200% modulus value in 23 degreeC is 4.7-13.8MPa after hardening is preferable.
It is preferable that the 200% modulus value can be within such a range. If the edge layer 501 is formed to be less than the 200% modulus value of 4.7 MPa, the edge deformation during cleaning becomes large and the wear resistance is lowered. This is because if it exceeds 13.8 MPa, it is difficult to disperse the stress generated in the vicinity of the edge during cleaning, and wear resistance may be reduced.
In this respect, it is preferable that the 200% modulus value of the polyurethane elastic body can be set to 8.0 to 11.5 MPa after curing, and the 200% modulus value of the polyurethane elastic body is set to 8.5 to 10. What can be made 5 MPa is more preferable.

  The “200% modulus value” can be measured using a dumbbell-shaped test piece (No. 3) according to JIS K 6251.

The filler contained in the polyurethane resin composition used for forming the edge layer 501 is organic as long as the filler can be dispersed in a polyurethane elastic body with a maximum particle size of 100 nm or less. There are no particular restrictions such as a system filler or an inorganic filler.
That is, normally, as these fillers, those having a maximum primary particle size of substantially 100 nm or less are used.

Examples of the organic filler include fluororesin powder such as polytetrafluoroethylene, silicone resin powder and the like, and examples of the inorganic filler include tin oxide, zinc oxide, titanium oxide, aluminum oxide, and iron oxide. And metal oxide particles such as silicon oxide (hereinafter also referred to as “silica”), metal particles, and mineral particles such as montmorillonite.
In addition, since the mechanical strength of the polyurethane elastic body can be improved while suppressing an increase in the hardness of the polyurethane elastic body, and the effect of reducing the friction coefficient of the polyurethane elastic body is excellent, the filler includes silica particles. Is preferably used, and silica particles having primary particles having a particle diameter of 20 to 30 nm are particularly preferably used.
The state of the primary particles of the filler having a particle size of 100 nm or less can be directly observed with a transmission electron microscope (TEM).

Depending on the type of these fillers, for example, when silica particles are used for the polyurethane elastic body of the edge layer 501 of the cleaning blade 50, the content in the edge layer 501 exceeds 0% by volume. It is preferable that the volume is not more than%.
The content of the filler in the polyurethane elastic body can usually be carried out by adjusting the blending of the polyurethane resin composition.

  The thermosetting polyurethane resin component is not particularly limited, and can contain a polyol, a polyisocyanate, and, if necessary, a crosslinking agent.

It does not specifically limit as said polyol, For example, polyester polyol, polyether polyol, polycaprolactone polyol etc. can be mentioned.
Of these, polyester polyols and polycaprolactone polyols are preferable because they prevent slipping of residual toner on the surface of the photoreceptor 10 and have excellent wear resistance.
These may be used alone or in combination of two or more.

The polyol preferably has a number average molecular weight of 1,000 to 3,000.
By using the polyol within the above range, it is possible to effectively prevent the toner remaining on the surface of the photoreceptor 10 from slipping through.

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 ethylene glycol, 1,4-butanediol, trimethylolpropane, diethylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, and triethylene glycol. Examples include aliphatic glycols, 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 these, the dicarboxylic acid is preferably an aliphatic dicarboxylic acid, and more preferably adipic acid, from the viewpoint that the residual toner on the surface of the photoreceptor 10 can be more reliably prevented.
As the glycol, aliphatic glycol is preferable, and ethylene glycol, 1,4-butanediol, and trimethylolpropane are more preferable.

Examples of the polyether polyol include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymers thereof.
Among these, polytetramethylene glycol is preferable because it can prevent the residual toner from slipping on the surface of the photoreceptor 10.

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.
Preferred 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 dilaurate, stannous chloride, and stannous bromide. Used.
In addition to the 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 isocyanate is preferred because it can prevent the residual toner from slipping on the surface of the photoreceptor 10.

Examples of the aliphatic isocyanate include 1,6-hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate.
In addition, there may be mentioned isocyanurate bodies, biuret bodies and modified adduct bodies of hexamethylene diisocyanate and isophorone diisocyanate.
Examples of the alicyclic isocyanate include alicyclic diisocyanates such as isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, and norbornane diisocyanate (NBDI).
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 preferable, and MDI is particularly preferable in terms of preventing slipping of residual toner on the surface of the photoreceptor 10.

Examples of the crosslinking agent used in the polyurethane resin composition include ethylene glycol, propylene glycol, butanediol, hexanediol, diethylene glycol, trimethylolpropane, glycerin, hydrazine, ethylenediamine, diethylenetriamine, 4,4′-diaminodiphenylmethane, Examples include 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 preferred because they can more reliably prevent slipping of residual toner and the like on the surface of the photoreceptor 10. Particularly preferred are ethylene glycol, 1,4-butanediol, and trimethylolpropane.

The polyurethane elastic body of the edge layer 501 can be produced by a known method using such raw materials, for example, using a catalyst in an appropriate organic solvent as necessary, and the equivalent ratio of each raw material. Can be formed by reacting with NCO / OH = 1.02 to 1.18, or by melt reaction without solvent.
Further, it can be formed by a one-shot method, a prepolymer method, or the like in which all raw materials are reacted simultaneously.

  When this prepolymer method is used, for example, a polyol and isocyanate subjected to dehydration treatment are mixed, and a prepolymer obtained by reacting at a temperature of 50 to 80 ° C. for 10 to 600 minutes is added with a crosslinking agent or the like. A method of curing by pouring into a mold or the like can be adopted. When the one-shot method is used, for example, a dehydrated polyol and a crosslinking agent are weighed, and a polyisocyanate is further added thereto. In addition, a method of curing by weighing, mixing, casting into a mold or the like can be employed.

The polyurethane resin composition used for forming the base layer 502 of the elastic member 50b uses the same raw materials as those used for forming the edge layer 501 such as the polyol and the polyisocyanate, except that the filler is not included. Can do.
However, it is preferable that the polyurethane resin composition used for forming the base layer 502 can form a polyurethane elastic body having a JIS A hardness of about 65 to 80 ° at 23 ° C. after curing.
It is preferable that such hardness can be obtained after curing. If the base layer 502 is formed to have a JIS A hardness of less than 65 °, the edge of the elastic member 50b is easily caught during cleaning, and buckling is prevented. This is because it may be easily generated.
Moreover, when it exceeds 80 degrees, there exists a possibility that the suppression effect of the stress concerning an edge may reduce.
In this respect, the polyurethane resin composition used for forming the base layer 502 is preferably one that can form a polyurethane elastic body having a JIS A hardness of 65 to 68 ° after curing.

Moreover, as a polyurethane resin composition used for formation of this base layer 502, what can form a polyurethane elastic body whose impact resilience is 5 to 30% is preferable after hardening.
It is preferable that the rebound resilience be in such a range. If the base layer 502 is formed to have a rebound resilience of less than 5%, the cleaning performance under low temperature and low humidity may be hindered. This is because the damper effect may be reduced.
In this respect, a polyurethane resin composition capable of forming a polyurethane elastic body having a rebound resilience of 8 to 26% after curing is preferable, and a polyurethane elastic body having a rebound resilience of 10 to 20% can be formed after curing. Is more preferable.

Moreover, as a polyurethane resin composition used for formation of this base layer 502, what can form the polyurethane elastic body whose 200% modulus value in 23 degreeC is 3.5-12 Mpa after hardening is preferable.
It is preferable that the 200% modulus value be in such a range. If the base layer 502 is formed to have a 200% modulus value of less than 3.5 MPa, there is a risk of buckling during cleaning, which exceeds 12 MPa. This is because the damper effect may be reduced.
In this respect, the polyurethane resin composition used for forming the base layer 502 is preferably one that can form a polyurethane elastic body having a 200% modulus value of 4.0 to 10.0 MPa after curing. More preferably, a polyurethane elastic body having a 200% modulus value of 4.0 to 8.0 MPa can be formed.

  Regarding the thicknesses of the edge layer 501 and the base layer 502 in the cleaning blade 50, 0.05 ≦ {when the thickness of the edge layer 501 is E (mm) and the thickness of the base layer 502 is B (mm). It is preferably formed so as to satisfy the relationship of E / (E + B)} ≦ 0.75, and formed so as to satisfy the relationship of 0.25 ≦ {E / (E + B)} ≦ 0.75. Is more preferable.

Further, the thickness (E) of the edge layer 501 is preferably more than 50 μm, and more preferably 0.2 to 2.0 mm.
By setting the thickness of the edge layer 501 within such a range, both the cleaning performance and the wear resistance can be achieved, and the service life of the cleaning blade can be prolonged.

  As the support member 50a, a rigid metal plate, a synthetic resin plate, a ceramic plate, or the like that can support the elastic member 50b can be used.

  The adhesive layer 51 for bonding the support member 50a and the elastic member 50b is usually an ethylene-vinyl acetate copolymer (EVA) system, although it depends on the material of the elastic member 50b and the support member 50a to be bonded. A polyamide-based, polyurethane-based, or polyester-based hot melt adhesive, a curable adhesive, or the like can be used.

Next, a method for producing such a cleaning blade 50 will be described by taking an example in which an elastic body is produced by a centrifugal molding method using a centrifugal molding machine.
This centrifugal molding method is to form a cylindrical body having a relatively uniform thickness by pouring a thermosetting material into the inner surface of a heated cylindrical mold that rotates at high speed and curing it. By cutting out a planar member from the cylindrical body, a member having excellent thickness accuracy can be easily formed.

FIG. 3A is an explanatory diagram for explaining an example of a centrifugal molding machine, and shows a side surface of the centrifugal molding machine and a partially internal state.
(B) is the XX 'sectional view taken on the line in (a).
As shown in FIG. 3, the centrifugal molding machine 100 has a bottomed cylindrical shape having a closed end 111 on the side and an open end 112 on the other side, and the centrifugal molding machine 100 is centrifuged in a state where the bottomed cylinder is placed horizontally. A mold 110 arranged in the molding machine 100, a heater 120 for heating the mold 110, and a motor 130 for rotating the mold 110 around the central axis of the cylindrical shape are provided.

Further, in the centrifugal molding machine 100, the mold 110 and the heater 120 are accommodated in an overall substantially rectangular heat insulation chamber 150 having an opening / closing door 140.
The heat insulation chamber 150 is formed with a rectangular internal space large enough to accommodate the mold 110, and the mold 110 has its open end 112 facing the door 140 side. The heat insulation chamber 150 is accommodated.
The heater 120 is disposed so as to surround the mold 110 from all sides, and is provided in a state of being fixed to all six inner walls of the heat insulating chamber 150.

The heat insulation chamber 150 is provided with a through hole in the wall on the opposite side of the door 140, and the mold 110 is blocked by a shaft 160 extending from the outside of the heat insulation chamber 150 into the heat insulation chamber 150 through the through hole. It is pivotally supported on the end 111 side.
The shaft 160 is arranged coaxially with the central axis of the mold 110 and is fixed to the through hole using a mechanical seal.
A pulley 161 is attached to the shaft 160 outside the heat insulating chamber 150, and the pulley 161 and the motor of the shaft 160 are rotated so as to rotate as the pulley 132 attached to the rotating shaft 131 of the motor 130 rotates. A transmission belt 170 is stretched between 130 pulleys 132.

  That is, the centrifugal molding machine illustrated in FIG. 3 can open the opening / closing door 140 of the heat insulation chamber 150 to allow the material to flow into the mold 110 from the open end 112 side of the mold 110, and The mold 110 can be rotated around the central axis by driving the motor 130 while heating the mold 110 (inflowed material) from the outside.

  Next, a method for producing the plate-like elastic member 50b of the cleaning blade 50 using such a centrifugal molding machine 100 will be described.

First, an uncured polyurethane resin composition for forming the edge layer 501 and the base layer 502 of the elastic member 50b is prepared.
At this time, the uncured polyurethane resin composition is appropriately liquid (hereinafter also referred to as “polyurethane resin solution”) using a solvent or the like so that the uncured polyurethane resin composition can be suitably used for the centrifugal molding method. Adjust so that
The filler is dispersed in the polyurethane resin solution used to form the edge layer 501. The filler is dispersed in the polyurethane resin solution in advance for the polyol used in the polyurethane resin solution. Is preferred.

That is, it is preferable to employ a method in which a polyol and a filler are mixed and stirred in advance to prepare a dispersion in which the filler is dispersed in the polyol, and then a component such as polyisocyanate and a crosslinking agent is mixed in the dispersion. .
At this time, since components such as polyisocyanate and a crosslinking agent are added later to dilute the dispersion, the dispersion is usually more concentrated than the filler concentration in the edge layer 501 to be finally formed. A filler is contained at a high concentration.

The filler can be dispersed in the polyol by employing a general mixing and stirring means.
Among them, the entire dispersion liquid can be sheared, and it can be carried out using a stirring means such as a bead mill in that it can more reliably prevent filler aggregation in the finally obtained polyurethane resin solution. Is preferred.
At this time, mixing and stirring the polyol and the filler while confirming whether the dispersion state of the filler in the polyol is a maximum particle size of 100 nm or less by appropriately collecting a dispersion in which the filler is dispersed in the polyol. Is also possible.

  Moreover, about the method of mixing components, such as polyisocyanate and a crosslinking agent, with the dispersion liquid which disperse | distributed the filler to this polyol, it can implement by employ | adopting a general mixing stirring means.

  Similar to the method of mixing components such as polyisocyanate and crosslinking agent into the dispersion in which filler is dispersed in this polyol, the polyurethane resin solution used to form the base layer 502 is generally made of polyol, polyisocyanate, crosslinking agent and the like. It can be produced by mixing and stirring using a typical mixing and stirring means.

  Next, an elastic member 50b in which a two-layer structure of the edge layer 501 and the base layer 502 is formed by centrifugal molding using the edge layer polyurethane resin solution and the base layer polyurethane resin solution.

In addition, in the molded product by the centrifugal molding method, the surface (hereinafter also referred to as “air side surface”) that was inside at the time of molding is easy to obtain a mirror-like smooth surface, but is in contact with the mold 110. The accuracy of the surface (hereinafter also referred to as “mold contact surface”) is affected by the roughness of the inner peripheral surface of the mold 110.
For this reason, normally, when the elastic member 50b of the cleaning blade 50 is manufactured by this centrifugal molding method, the “air side surface” is used as the surface side to be in contact with the photosensitive member 10.

However, when the polyurethane resin solution is allowed to flow into the mold 110, foreign matter such as dust is mixed in or bubbles are generated in the polyurethane resin solution. There is a risk of moving to the “air side” and curing near the surface.
If foreign matter or bubbles are present in the vicinity of the surface, the portion exhibits an elastic behavior different from that of the surroundings, which may result in a defective product that does not function as the cleaning blade 50.

Further, the accuracy of the thickness of the molded product by the centrifugal molding method (the difference between the maximum thickness and the minimum thickness found in the cylindrical body formed by the centrifugal molding method) is the deflection accuracy of the mold 110 (the mold 110 is rotated around the rotation axis). The difference between the maximum value and the minimum value of the distance from the rotation axis to the inner peripheral surface of the mold observed when it is rotated once.
Therefore, in some cases, there is a risk that the yield when cutting the elastic member 50b used for the cleaning blade 50 from the cylindrical body formed by the centrifugal molding method is lowered.

  In response to this, the elastic member 50b for the cleaning blade can be manufactured by performing a centrifugal molding method as described below, with excellent surface smoothness of the edge layer 501 and high yield.

First, before the edge layer polyurethane resin solution or the base layer polyurethane resin solution is allowed to flow into the mold 110, liquid silicone rubber is allowed to flow into the mold 110 of the centrifugal molding machine, and the mold 110 is rotated while being liquid. A silicone rubber cylindrical body (hereinafter also referred to as “silicone rubber layer 500”) is formed on the inner peripheral surface of the mold 110 by curing the silicone rubber.
Next, without removing the silicone rubber from the inner peripheral surface of the mold 110, the polyurethane resin solution for the edge layer is allowed to flow into the mold 110 and the polyurethane resin solution for the edge layer is cured while rotating the mold 110. An edge layer 501 is formed on the inner peripheral surface side of the rubber.
Further, without removing the edge layer 501, the base layer polyurethane resin solution is allowed to flow into the mold 110 and the base layer polyurethane resin solution is cured while rotating the mold 110 to form the base layer 502 (FIG. 4 (see a partially enlarged cross-sectional view of part B in FIG. 3).

As a result, as shown in FIG. 4, a three-layer structure of silicone rubber layer 500 / edge layer 501 / base layer 502 is formed from the inner peripheral surface side (outer side) of the mold 110.
The silicone rubber layer 500 can be easily peeled from the surface of the edge layer 501. After forming the three-layer structure, a cylindrical body is obtained in which the edge layer 501 is formed on the outer peripheral side and the base layer 502 is formed on the inner peripheral side. The elastic member 50b used for the cleaning blade 50 can be produced by cutting out from the cylindrical body into a plate shape.

For the formation of the silicone rubber layer 500 used in the centrifugal molding method, one obtained from an addition curable silicone rubber composition is preferable. As this addition curable silicone rubber composition, an aliphatic unsaturated carbon bond bonded to a silicon atom is used. An organopolysiloxane having at least two hydrogen groups, an organohydropolyene polysiloxane having at least two hydrogen atoms bonded to silicon atoms, and a platinum-based catalyst are preferred.
In this case, a molded body of silicone rubber having high runout accuracy is formed, and the elastic member 50b having good thickness accuracy can be manufactured.
Moreover, the surface defect in the edge layer 501 of the elastic member 50b can be improved.
Furthermore, the wear resistance and cleaning performance of the obtained cleaning blade 50 can be made compatible.
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 becomes a base polymer of the addition-curable silicone rubber composition, and has an average composition formula (1): R ¹ _a R A compound represented by ² _b SiO _{[4- (a + b)] / 2} is preferable.
In the formula (1), 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, isopropyl 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, R ² excludes the aliphatic unsaturated hydrocarbon group.
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 Allyl 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.

In the formula (1), 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, 1.8 ≦ (a + b) ≦ 2.25.
In the organopolysiloxane represented by the formula (1), two or more of the 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 formula (1), 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 be linear, branched or cyclic in its skeleton, but the main chain portion has diorganosiloxane units as repeating units, and the molecular chain ends have triorganosiloxane units. What it has is preferable.
Examples of the triorganosiloxane units (triorganosiloxane units in which only substituted or unsubstituted monovalent hydrocarbon groups are bonded to silicon atoms) include vinyl groups such as trimethylsiloxane units, dimethylphenylsiloxane units, and methyldiphenylsiloxane units. 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 (the 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, etc.) 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 (2): R ³ _c H _d SiO _{[4- (c + d)] / 2]} .
R ³ represents the same group as R ² .
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.

C and d in the formula (2) represent numbers satisfying the relations 0.8 ≦ c ≦ 2.2, 0.002 ≦ d ≦ 1, and 0.8 <(c + d) <3, respectively. Preferably, the numbers satisfy the relations of 1 ≦ c ≦ 2.2, 0.01 ≦ d ≦ 1, and 1.8 ≦ (c + d) ≦ 2.5.
The organohydrodiene polysiloxane represented by the formula (2) may have a skeleton that is linear, branched or cyclic, and contains a diorganohydrodienesiloxane unit and a SiO ₂ unit. A resinous material having a three-dimensional network structure appropriately containing a triorganosiloxane unit or a diorganosiloxane unit may be used.

The organohydrodiene polysiloxane is a compound in which at least 2, preferably 3 or more hydrogen atoms per molecule are bonded to silicon atoms to form SiH groups.
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 of the Si atoms in the molecular chain, or may be bonded to both.
The degree of polymerization of the organohydropolyenepolysiloxane (the number of Si atoms in the molecule) is preferably 3 to 400, and particularly preferably 4 to 300.

Specific examples of the organohydrodiene polysiloxane include, for example, methyl hydrodiene cyclopolysiloxane, methyl hydrodiene siloxane / dimethyl siloxane cyclic copolymer, trimethylsiloxy group-blocked methyl hydrodiene polysiloxane, trimethylsiloxy group of both terminals Blocked dimethylsiloxane / methylhydrodienesiloxane copolymer, both ends dimethylhydrosiloxy group-blocked dimethylpolysiloxane, both ends dimethylhydrosiloxy group-blocked dimethylsiloxane / methylhydrogenenesiloxane copolymer, both ends trimethylsiloxy group-blocked methyl Hydrodiene siloxane / diphenyl siloxane copolymer, trimethylsiloxy group-capped methylhydrodiene siloxane / diphenyl siloxane Down-dimethylsiloxane copolymer, both ends dimethyl hydrogen diene siloxy group methylhydrogenpolysiloxane blocked diene-dimethylsiloxane-diphenylsiloxane copolymers, (CH _{3) 2} HSiO _1/2 units and (CH _{3) 3} HSiO _1/2 Copolymer consisting of units and SiO _4/2 units, copolymer consisting of (CH ₃ ) ₂ HSiO _1/2 units and SiO _4/2 units, (CH ₃ ) ₂ HSiO _1/2 units and SiO _{4 And a} copolymer composed of _{/ 2} units and (C ₆ H ₅ ) ₃ HSiO _1/2 units.

  In the addition-curable silicone rubber composition, the mixing ratio 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 thereof 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 size 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 this treating agent in-process.
The reinforcing silica content is preferably 5 to 200 parts by weight with respect to 100 parts by weight 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, brand name "TSE3032" (made by GE Toshiba Silicone), brand name "KE103" (made by Shin-Etsu Polymer Co., Ltd.) etc. can be mentioned, for example.

  An example of the centrifugal molding method using such an addition curable silicone rubber composition is as follows. For example, the constituent material of a silicone rubber molded body such as the above addition curable silicone rubber composition is preheated to 30 to 50 ° C. By injecting into the mold 110 of the centrifugal molding machine 100 and curing for 120 to 180 minutes, a silicone rubber layer 500 (hereinafter also referred to as “silicone rubber molded body”) can be formed.

The thickness of the silicone rubber layer 500 formed at this time is preferably 0.5 to 3.0 mm.
If it is less than 0.5 mm, the thickness of the silicone rubber layer 500 is too thin, so that there is no strength, and when peeling from the mold 110, there is a possibility that everything cannot be peeled cleanly, There is a possibility that the heat of the mold 110 cannot be effectively transmitted and the characteristics of the formed elastic member 50b are adversely affected.

In order to form the edge layer 501 on the silicone rubber molded body (silicone rubber layer 500), the centrifugal molding machine is preheated to 130 to 150 ° C., and the polyurethane resin solution for the edge layer is injected and cured for 5 to 10 minutes. Let
Subsequently, a polyurethane resin solution for forming the base layer is injected and cured for 25 to 50 minutes.

  After the formation of the base layer 502, the cylindrical body formed here with the edge layer 501 on the outer peripheral side and the base layer 502 formed on the inner peripheral side is peeled off from the silicone rubber molded body, and then the centrifugal molding machine. The elastic member 50b for the cleaning blade 50 can be manufactured by taking it out from 100 and cutting it into a predetermined size.

  The method for adhering the elastic member 50b to the support member 50a through the adhesive layer 51 is not particularly limited, and a method generally used when manufacturing a blade for an electrophotographic apparatus is adopted. Can do.

The cleaning blade 50 thus manufactured uses a polyol in which a filler is dispersed in a state where the particle size is 100 nm or less for forming the edge layer 501.
In addition, when the polyurethane resin composition for the edge layer is produced, it is further diluted with a component such as polyisocyanate, so that the dispersion state of the filler in the polyurethane resin composition also has a maximum particle size of 100 nm or less.
Therefore, the dispersion state of the filler in the edge layer 501 of the cleaning blade 50 also has a maximum particle size of 100 nm or less.
However, for example, when using a filler that has not been subjected to surface treatment or the like, there is a risk of aggregation during the curing reaction.
For this reason, it is preferable to subject the filler to a surface treatment in that the dispersion state of the filler in the polyurethane elastic body after curing can be more surely set to a maximum particle size of 100 nm or less.

In addition, about the particle size of the primary particle of the filler in this edge layer 501, and the aggregate particle, for example, mapping by the element peculiar to a filler is implemented with respect to the surface of the edge layer 501 using a scanning Auger electron spectrometer. Can be confirmed.
For a finer dispersion state, for example, using a sample horizontal X-ray diffractometer (trade name “RINT-TTR III”) manufactured by Rigaku Corporation, the conditions of CuKα ray, tube voltage 50 kV, and current 300 mA are used. Thus, it can be confirmed by performing an X-ray diffraction analysis on the surface of the edge layer.
At this time, particles having a particle size of 100 nm or less in the edge layer (primary particles or agglomeration) are obtained by performing X-ray diffraction at a small angle, such as by measuring 0.002 ° between 2θ between 0.08 and 1.2 ° The dispersion state of the particles can be confirmed.

By setting the dispersion state of the filler in the edge layer 501 to a maximum particle size of 100 nm or less, the mechanical properties such as the tear strength of the edge layer 501 are improved while suppressing the edge layer 501 from having a high hardness. Can be.
Moreover, by using silica particles having a primary particle size of 20 to 30 nm as the filler, not only these effects can be exhibited more significantly, but also the friction coefficient of the edge layer 501 can be reduced.
Therefore, generation of cracks and wear during use can be suppressed, and the service life of the cleaning blade 50 can be extended.

Furthermore, the elastic member 50b of the cleaning blade 50 described in the present embodiment is manufactured by centrifugal molding, and before the edge layer polyurethane resin solution is allowed to flow into the mold 110, the silicone rubber layer 500 is formed. It is made by forming.
Before the edge layer polyurethane resin solution is allowed to flow, by forming the silicone rubber layer 500, from the rotation axis observed when the mold 110 is rotated around the rotation axis to the air side surface of the silicone rubber layer. The difference between the maximum value and the minimum value of the distance can be made sufficiently small with respect to the deflection accuracy of the mold 110, and the thickness accuracy of the elastic member 50b for the cleaning blade can be sufficiently improved.
That is, the cleaning blade 50 described in the present embodiment has an excellent productivity because the dimensional accuracy of the elastic member 50b is excellent and the yield can be improved.

Further, since the air side surface of the silicone rubber layer 500 is formed in a state having excellent smoothness, the surface of the edge layer 501 that is centrifugally molded in contact with the air side surface of the silicone rubber layer 500 is made smooth. It can be made excellent.
Moreover, even when foreign substances such as dust or bubbles are included in the polyurethane resin solution for forming the edge layer when forming the edge layer 501, these are not the same as those on the air layer side of the edge layer 501, that is, the base layer 502. Therefore, the influence on the surface of the edge layer 501 can be suppressed.
That is, the cleaning blade 50 described in the present embodiment also has an effect of being excellent in cleaning performance.

  In the present embodiment, the amount of filler used can be reduced, and a polyurethane elastic body containing a filler is used only for the edge layer, so that the blade can be produced at low cost. In the present invention, the blade for an electrophotographic apparatus has been described by using an elastic member having a base layer formed by the above method. However, in the present invention, the base layer is made of a polyurethane elastic body containing no filler. It is not limited to the one provided with the formed elastic member.

  Moreover, in this embodiment, the elastic member has a laminated structure of an edge layer and a base layer in that the physical properties mainly required for the surface (edge portion) and the physical properties required for the entire elastic member can be easily achieved. Although the case has been described as an example, in the present invention, the elastic member is not limited to the one having such a two-layer laminated structure, and the case where the elastic member has a single-layer or three-layer or more laminated structure is also described. This is the intended scope of the invention.

  Further, in the present embodiment, the case where the multilayer elastic member is manufactured by the centrifugal molding method is described as an example in that the multilayer elastic member can be manufactured with excellent quality and high yield. However, in the present invention, the blade for the electrophotographic apparatus is used. Is not limited to those in which a centrifugal molding method is used during production.

  In this embodiment, wear resistance, tear resistance, etc. are particularly strongly demanded, and the elastic member of the cleaning blade is used for the electrophotographic apparatus of the invention in that the effects of the present invention can be exhibited more remarkably. The member is not limited to the cleaning blade, and for example, other blades such as a developing blade can be expected to have the same effect as the cleaning blade exemplified in the present embodiment.

Furthermore, the blade for an electrophotographic apparatus of the present invention can be applied to an electrophotographic apparatus other than the electrophotographic apparatus exemplified in this embodiment.
For example, the blade for an electrophotographic apparatus of the present invention can be applied to a liquid developing electrophotographic apparatus using liquid toner.

EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.
(Examples 1-5)
(Adjustment of polyurethane resin solution)
A polyurethane resin solution was prepared according to the formulation shown in Table 1.
When preparing the polyurethane resin solution, first, silica particles that have been subjected to surface treatment with a primary particle size of 20 to 30 nm in advance are dispersed in a polyol with a maximum particle size of 100 nm or less (aggregated particles are formed). The silica-containing polyol (silica particle content: 25% by mass) is dispersed in a state where the particle size is 100 nm or less), and the silica-containing polyol is a polyol containing no silica. The content of silica particles in the polyurethane resin solution prepared by moderate dilution is as shown in Table 1, and the ratio of prepolymer to polyol is by weight (prepolymer: polyol) ≈ (100: 91 ).
The mixing of the silica-containing polyol and the polyol was carried out using a high-speed stirrer and then defoamed after stirring.
Next, a prepolymer and a crosslinking agent were added to the mixture of the polyol and the silica-containing polyol, and the mixture was stirred again, followed by defoaming treatment to obtain a polyurethane resin solution to be used for the subsequent casting.

(Preparation of sample for evaluation)
This polyurethane resin solution was cast into a mold and cured at 140 ° C. for 60 minutes to produce blade elastic members of Examples 1-5.
Note that silicon elements were mapped to the elastic members of Examples 1 to 5 using a scanning Auger electron spectrometer, but particles having a size exceeding 100 nm were not observed.

(Comparative Example 1)
A polyurethane resin solution was prepared in the same manner as in Example 1 except that the silica-containing polyol was not used, and a blade elastic member was prepared using the polyurethane resin solution.

(Comparative Example 2)
A polyurethane resin solution was prepared using silica particles having the same particle size as in Example 1 and having no surface treatment so that aggregated particles were easily formed, and a blade elastic member was prepared using the polyurethane resin solution.
Agglomerated particles of 10 to 20 μm were observed in the obtained elastic member for blades.

(Example 6)
A polyurethane resin solution was prepared in the same manner as in Example 1 except that the composition in which the content of silica particles was 11% by mass (6.3% by volume) was used.
The obtained polyurethane resin solution had a high viscosity and was difficult to be cast into a mold for producing the blade elastic member of Example 1.
It was confirmed that the elastic body obtained by curing this polyurethane resin solution was in a dispersed state with a maximum particle size of 100 nm or less without any filler aggregation.

(Example 7)
A polyurethane resin solution was prepared in the same manner as in Example 1 except that titanium oxide particles having a primary particle size of 20 to 30 nm were used in an amount of 1% by mass (0.3% by volume) instead of silica particles. An elastic member for a blade was produced using the polyurethane resin solution.
It was confirmed that the blade elastic member was in a dispersed state having no maximum particle size of 100 nm or less without any filler aggregation.

(Example 8)
A polyurethane resin solution was prepared in the same manner as in Example 1 except that aluminum oxide particles having a primary particle size of 20 to 30 nm were used in an amount of 1% by mass (0.4% by volume) instead of silica particles. An elastic member for a blade was produced using the polyurethane resin solution.
It was confirmed that the blade elastic member was in a dispersed state having no maximum particle size of 100 nm or less without any filler aggregation.

Example 9
A polyurethane resin solution was prepared in the same manner as in Example 1 except that ferric oxide particles having a primary particle size of 20 to 30 nm were used in an amount of 1% by mass (0.2% by volume) instead of silica particles. Then, an elastic member for a blade was produced using the polyurethane resin solution.
It was confirmed that the blade elastic member was in a dispersed state having no maximum particle size of 100 nm or less without any filler aggregation.

(Example 10)
A polyurethane resin solution was prepared in the same manner as in Example 1 except that polytetrafluoroethylene particles having a primary particle size of 20 to 30 nm were used in an amount of 1% by mass (0.9% by volume) instead of silica particles. Then, an elastic member for a blade was produced using the polyurethane resin solution.
It was confirmed that the blade elastic member was in a dispersed state having no maximum particle size of 100 nm or less without any filler aggregation.

(Evaluation)
The following evaluation was carried out using the blade elastic member of each example and comparative example as an evaluation sample.

(Hardness)
According to JIS K 6253, it was measured by M method of the international rubber hardness (IRHD) test method using a Wallace Wallace hardness meter manufactured by Wallace.
Measurement conditions are 23 ° C. and 50% RH.

(Tensile test)
According to JIS K 7312, a tensile test is performed using a dumbbell-shaped test piece (JIS No. 3), and 100% modulus (M100), 200% modulus (M200), tensile strength, and elongation at break are measured. did.

(Tear strength)
According to JIS K 7312, the measurement was carried out using (B) an angled test piece without cut.

(Tensile modulus)
Using a dumbbell-shaped test piece (JIS No. 1), a tensile test was performed with a distance between marked lines of 40 mm, a load when the distance between the marked lines was extended by 5% was read, and a tensile elastic modulus was obtained by calculation.

(Permanent elongation)
An elongation test of 100% elongation × 10 minutes was performed under a temperature condition of 23 ° C., the dimensional change with respect to the initial value was measured, and the permanent elongation was obtained by calculation.

(Rebound resilience)
According to JIS K 7312, measurement was performed under four conditions of 10 ° C., 23 ° C., 40 ° C., and 55 ° C.

(Tan δ peak temperature)
According to JIS K 7244-4, using a test piece of 10 mm width × 50 mm length × 2.0 mm thickness, measurement frequency: 10 Hz, measurement temperature range: -40 to 60 ° C. tensile storage modulus (E ′ ), Tensile loss elastic modulus (E ″), tensile loss coefficient (tan δ) were measured, temperature dependency was observed, and tan δ peak temperature was measured.

(Coefficient of friction)
The dynamic friction coefficient was measured according to JIS K 7312.
The results are shown in Table 1.

From each evaluation result shown in Table 1, the polyurethane elastic body contained in a dispersed state in which the filler has a maximum particle size of 100 nm or less is improved in mechanical strength such as tear strength while suppressing an increase in hardness. I know you get.
Moreover, in the comparative example 2, although the raise of hardness was suppressed, intensity | strength was not able to be improved.

Schematic which shows the printing mechanism of an electrophotographic apparatus. Sectional drawing which shows the structure of the cleaning blade of this embodiment. (A) Explanatory drawing which shows the structure of a centrifugal molding machine. (B) The left X-X 'arrow directional cross-sectional view. The B section enlarged view in Fig.3 (a).

Explanation of symbols

1: printing mechanism, 10: photoconductor, 11: charging roller, 20: developing roller, 21: developing blade, 21a: support member, 21b: elastic member, 22: supply roller, 30: transfer roller, 40: fixing device 41a, 41b: fixing roller, 50: cleaning blade, 50a: support member, 50b: elastic member, 51: adhesive layer, 60: driving device, 61: timing belt (toothed belt), 62: timing pulley, 62a : Driven gear, 63: drive motor, 63a: drive gear, 64a, 64b: support pulley, 65a, 65b: transmission gear, 100: centrifugal molding machine, 110: mold, 111: closed end, 112: open end, 120 : Heater, 130: motor, 131: rotating shaft, 132: pulley, 140: door, 150: heat insulation chamber, 160: shaft, 161: pulley 70: transmission belt, 500: silicone rubber layer, 501: edge layer, 502: base layer, A: print medium, G: the transmission gear, T: Toner

Claims (4)

  An elastic member formed of a polyurethane elastic body having at least a surface containing a filler is provided, and the filler is dispersed in the polyurethane elastic body so as to have a maximum particle size of 100 nm or less. A blade for an electrophotographic apparatus.   2. The blade for an electrophotographic apparatus according to claim 1, wherein silica particles are used as the filler, and the polyurethane elastic body contains the silica particles in a proportion of more than 0% by volume and not more than 6% by volume. .   A plate-like elastic member is provided in which a laminated structure including at least two layers of an edge layer provided on the outermost surface side and a base layer formed on the back side of the edge layer is formed in the thickness direction; 3. The blade for an electrophotographic apparatus according to claim 1, wherein the edge layer is formed of the polyurethane elastic body, and the base layer is formed of an elastic body different from the edge layer.   The blade for an electrophotographic apparatus according to claim 3, wherein the base layer is formed of a polyurethane elastic body containing no filler.

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