JP6800697B2 - Cleaning blades, process cartridges and electrophotographic image forming equipment - Google Patents

Description

The present invention relates to a cleaning blade, a process cartridge, and an electrophotographic image forming apparatus used in an electrophotographic apparatus.

The electrophotographic apparatus is provided with a cleaning member in order to remove the toner remaining on the image carrier after transferring the toner image from the image carrier such as a photoconductor onto a transfer body such as paper or an intermediate transfer body. There is. Among these cleaning members, a cleaning blade using a plate-shaped elastic member is well known. In recent years, the diameter and spheroidization of toner have been promoted in response to the demand for higher image quality of electrophotographic images, and the toner remaining on the image carrier has become easy to slip through the cleaning blade. Therefore, the cleaning blade is required to have better cleaning performance.

Patent Document 1 discloses a cleaning blade in which the contact portion is made harder by increasing the concentration of the isocyanurate group at the contact portion of the cleaning blade made of polyurethane elastomer. It is disclosed that this makes it possible to reduce the friction between the image carrier and the cleaning blade. Further, Patent Document 2 discloses a cleaning blade in which the tip end portion of the cleaning blade is hardened and the physical properties inside the hardening treatment are controlled without further impairing the rubber elasticity.

Japanese Unexamined Patent Publication No. 2001-75451 Japanese Unexamined Patent Publication No. 2012-53311

The present invention is aimed at providing a cleaning blade capable of exhibiting more excellent cleaning performance. The present invention also aims to provide a process cartridge and an electrophotographic image forming apparatus that contribute to the stable formation of a high-quality electrophotographic image.

According to one aspect of the present invention, it is a cleaning blade including an elastic member and a support member for supporting the elastic member, and an edge and an edge are formed on a free end portion of the elastic member. And one or both of the first surface and the second surface have a cured surface, and the dynamic hardness of the cured surface is DHs (mN / μm ² ). In the cross section orthogonal to the longitudinal direction of the elastic member, the distance L from the edge on the straight line that bisects the angle of the edge is the maximum of the dynamic hardness at each position of 0 μm <L ≦ 100 μm. When the value is DHm (mN / μm ² ), a cleaning blade satisfying the relationship represented by the following equations (1) and (2) is provided.
Equation (1) 0.1 ≤ DHs ≤ 0.4
Equation (2) DHs <DHm.

Further, according to another aspect of the present invention, a process cartridge having the cleaning blade is provided. Further, according to another aspect of the present invention, an electrophotographic image forming apparatus having the cleaning blade is provided.

According to one aspect of the present invention, it is possible to obtain a cleaning blade capable of exhibiting more excellent cleaning performance. Further, according to another aspect of the present invention, it is possible to obtain a process cartridge and an electrophotographic image forming apparatus that contribute to the formation of a high-quality electrophotographic image.

It is a perspective view of the cleaning blade which concerns on this invention. FIG. 1A shows an example of an integrally molded type cleaning blade. FIG. 1B shows an example of an adhesive type cleaning blade. It is a figure which shows the state which the edge of a cleaning blade came into contact with a member to be cleaned when the process cartridge is stationary. The longitudinal direction (X direction) of the elastic member is the direction perpendicular to the paper surface in this figure. It is a figure which shows the state which a cleaning blade came into contact with a member to be cleaned at the time of operation of a process cartridge. It is a figure which shows the dynamic hardness of the hardened surface and the inside of an elastic member in Examples 1, 4 and 11, and Comparative Examples 1 and 4. It is a figure which shows the cut-out part of the measurement sample. FIG. 6A is a measurement diagram of the dynamic hardness of the cured surface. FIG. 6B is a measurement diagram of the dynamic hardness of the cross section orthogonal to the longitudinal direction of the elastic member. It is a figure which shows the measurement point of the dynamic hardness in the cross section orthogonal to the longitudinal direction of an elastic member. It is a figure which shows the measuring method of edge chipping.

Examples of the member to be cleaned to which the cleaning blade of the present invention is applied include an image carrier such as a photoconductor, an endless belt such as an intermediate transfer belt, and the like. Hereinafter, an embodiment of the cleaning blade of the present invention will be described in detail by taking a photoconductor as an example of a member to be cleaned.

<Configuration of cleaning blade>
1, FIG. 2 and FIG. 3 show an example of a cleaning blade according to the present invention. FIG. 1 is a schematic view showing the configuration of a cleaning blade. The cleaning blade of the present invention is composed of an elastic member 2 and a support member 3 that supports the elastic member 2. The elastic member has a cured surface in which either or both of the first and second surfaces forming an edge that abuts the member to be cleaned abuts the member to be cleaned. That is, from the viewpoint of improving the cleaning performance, the surface abutting the member to be cleaned and at least one of the first surface and the second surface on both sides of the edge of the cleaning blade abutting the member to be cleaned and the surface thereof. A hardened region is formed inside near the surface. In FIG. 1, the "longitudinal direction" of the cleaning blade is the X direction, and the "short direction" and the "thickness direction" are the Z direction and the Y direction.

In the cleaning blade of the present invention, the "free end" of the elastic member is the end of the elastic member on the opposite side of the end supported by the support member. Further, the "free end portion" of the elastic member is the free end and its vicinity. The "edge" is a contact portion of a cleaning blade that comes into contact with a member to be cleaned, and is a ridgeline portion formed by the intersection of a first surface and a second surface. Further, the "first surface" is, for example, the lower surface 5 or the elevation 6 of the elastic member in FIG. 2, and the "second surface" is, for example, the elevation 6 or the lower surface of the elastic member in FIG. It is 5. Hereinafter, the lower surface 5 will be referred to as a first surface, and the elevation 6 will be referred to as a second surface. The free end of the elastic member and its vicinity may be referred to as the "tip portion" of the elastic member or the "tip portion" of the cleaning blade.

FIG. 1A is an example of a cleaning blade in which the elastic member 2 and the support member 3 are integrally molded. The cleaning blade of this example can be obtained by arranging a support member in a mold, injecting a raw material composition such as a polyurethane elastomer into the mold, heating the mold, reacting and curing the blade, and removing the mold. After the mold is removed, the tip of the free end of the elastic member in the Z direction and both ends of the elastic member in the X direction can be cut as needed. The step of forming the cured region at the tip of the elastic member may be before or after cutting. As a result, a cleaning blade in which the elastic member 2 and the support member 3 are integrated can be obtained.

FIG. 1B shows an adhesive type cleaning blade obtained by separately molding a sheet for an elastic member, cutting it into strips to form an elastic member 2, and adhering this to the support member 3 with an adhesive or the like. Is an example of. The step of forming the cured region 4 at the tip of the elastic member may be before or after the elastic member is adhered to the support member.

[Support member]
The material constituting the support member of the cleaning blade of the present invention is not particularly limited, and examples thereof include the following materials. Metallic materials such as steel sheets, stainless steel sheets, galvanized steel sheets, chrome-free steel sheets, resin materials such as 6-nylon and 6,6-nylon. Further, the structure of the support member is not particularly limited. As shown in FIG. 2 and the like, one end of the elastic member of the cleaning blade is supported by the support member.

[Elastic member]
Examples of the material constituting the elastic member of the cleaning blade of the present invention include the following materials. Polyurethane elastomer, ethylene-propylene-diene copolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), fluorine Rubber, silicone rubber, epichlorohydrin rubber, NBR hydride, polysulfide rubber, etc. As the polyurethane elastomer, a polyester urethane elastomer is preferable because it has excellent mechanical properties. Polyurethane elastomer is a material obtained mainly from raw materials such as polyisocyanate, polyol, chain extender, catalyst, and other additives. Hereinafter, these raw materials will be described in detail.

Examples of the polyisocyanate include the following. 4,4'-Diphenylmethane diisocyanate (MDI), 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), xylene diisocyanate (XDI), 1,5 -Naftylene diisocyanate (1,5-NDI), p-phenylenediocyanate (PPDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), tetramethylxylene Diisocyanate (TMXDI), carbodiimide-modified MDI, polymethylenephenyl polyisocyanate (PAPI). Among these, MDI is preferable because a polyurethane elastomer having excellent mechanical properties can be obtained.

Examples of the polyol include the following. Polyester polyols such as polyethylene adipate polyol, polybutylene adipate polyol, polyhexylene adipate polyol, (polyethylene / polypropylene) adipate polyol, (polyethylene / polybutylene) adipate polyol, (polyethylene / polyneopentylene) adipate polyol; ring-opening caprolactone Polycaprolactone-based polyol obtained by polymerization; polyether polyol such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol; polycarbonate diol. These can be used alone or in combination of two or more. Among the above polyols, polyester polyols are preferable because polyurethane elastomers having excellent mechanical properties can be obtained.

As the chain extender, a polyurethane elastomer chain can be extended, and for example, glycol is used. Examples of such glycols include the following. Ethylene glycol (EG), diethylene glycol (DEG), propylene glycol (PG), dipropylene glycol (DPG), 1,4-butanediol (1,4-BD), 1,6-hexanediol (1,6-HD) ), 1,4-Cyclohexanediol, 1,4-cyclohexanedimethanol, xylylene glycol (terephthalyl alcohol), triethylene glycol. In addition to the above glycols, other polyhydric alcohols can also be used, and examples thereof include trimethylolpropane, glycerin, pentaerythritol, and sorbitol. These can be used alone or in combination of two or more.

As the catalyst, a commonly used catalyst for curing a polyurethane elastomer can be used, and examples thereof include a tertiary amine catalyst, and specific examples thereof include the following. Amino alcohols such as dimethylethanolamine, N, N, N'-trimethylaminopropylethanolamine; trialkylamines such as triethylamine; tetraalkyls such as N, N, N'N'-tetramethyl-1,3-butanediamine Diamine; triethylenediamine, piperazine-based compound, triazine-based compound. In addition, organic acid salts of metals such as potassium acetate and potassium alkali octylate can also be used. In addition, metal catalysts commonly used for urethanization, such as dibutyltin dilaurate, can also be used. These can be used alone or in combination of two or more.

Additives such as pigments, plasticizers, waterproofing agents, antioxidants, ultraviolet absorbers, and light stabilizers can be further added to these raw material compositions, if necessary.

In the elastic member of the present invention, the angle of the edge formed by the first surface and the second surface is not particularly limited, but is usually about 85 to 95 degrees.

The international rubber hardness (IRHD) of the elastic member of the present invention is preferably 60 degrees or higher, more preferably 65 degrees or higher.

[Formation site of hardened region]
The cleaning performance is improved when the portion where the cured region is formed at the tip of the elastic member is at least one surface of the first surface and the second surface abutting the member to be cleaned and the inside in the vicinity of the surface. It is effective as a means to realize. When the member to be cleaned is a photoconductor, the image forming region on the surface of the photoconductor is brought into contact with the edge of the cleaning blade and cleaned.

The cured region is further formed on another surface of the tip of the elastic member, that is, a surface facing the first surface (the surface of reference numeral 10 in FIG. 2) and both end faces in the longitudinal direction of the elastic member (reference numeral 9 in FIG. 1). It may be formed on the surface of). In this case, the rigidity of both end faces of the elastic member can be improved, and the turning of the cleaning blade can be further reduced.

[Method of forming hardened region]
The formation of the cured region in the elastic member can be performed by applying a material for forming the cured region to a region where high hardness is desired and curing the region. The material for forming the cured region is used after being diluted with a diluting solvent, if necessary, and can be applied by a known means such as dipping, spraying, dispenser, brush coating, and roller coating. As the material for forming the cured region, an isocyanate compound or the like described later can be used. In order to allow a high hardness region to exist inside the surface, it is necessary to sufficiently impregnate the elastic member with a material for forming a cured region (isocyanate compound or the like). Since impregnation is promoted by making the material for forming the cured region high in concentration and low viscosity, it is effective to heat the material for forming the cured region without diluting it. The material temperature is preferably 60 ° C. or higher.

Hereinafter, an example of a method for forming a cured region will be described with reference to an example in which an isocyanate compound is used as a material for forming the cured region. An elastic member coated with a material for forming a cured region may be referred to as a "precursor".

In order to allow a high hardness region to exist inside the surface of the elastic member, it is preferable to heat-treat the precursor after applying the material for forming the cured region. By the heat treatment, the viscosity of the material for forming the cured region existing on the surface of the elastic member is reduced, and the penetration and diffusion into the inside of the elastic member can be promoted. Examples of the heating method include a method of passing the precursor through the heating furnace and a method of blowing heating air onto the precursor, but the heating method is not particularly limited. For example, examples of the heating furnace include a radiant heating furnace and a circulating air heating furnace, and examples of the device for forming the heating air include a hot air heater and a far-infrared heater.

By setting the heating conditions to high temperature and / or for a long time, the cured region becomes wider, and the region having the highest hardness shifts to a position more inside from the surface of the elastic member. As the heating conditions, it is preferable to heat at least the surface temperature of the tip of the elastic member at 80 ° C. or higher for 3 minutes or longer. Even if the tip of the elastic member is continuously heated at a temperature of less than 80 ° C., the viscosity of the isocyanate compound does not decrease to the viscosity required for diffusion in the elastic member, so that the diffusion rate is slow and the surface of the elastic member is often covered. The isocyanate compound of the above is retained, and the hardness of the surface of the elastic member becomes the highest. The atmosphere of the heating furnace is preferably set to a temperature higher than 80 ° C. in order to make the surface temperature of the tip of the elastic member 80 ° C. or higher.

However, the temperature and time of this heat treatment differ depending on the amount of impregnation of the material for forming the cured region into the elastic member. Specifically, under the condition that the elastic member is sufficiently impregnated (material temperature for forming a cured region, 90 ° C., etc.), a high hardness region exists inside the surface of the elastic member under the heating furnace condition of 100 ° C. for 10 minutes. Can be made to. However, under the condition that the material is not sufficiently impregnated into the elastic member (material temperature for forming a hardening region is 60 ° C., etc.), the high hardness region does not exist inside the elastic member under the heating furnace condition of 100 ° C. for 10 minutes. The surface has the highest hardness. In this case, the heating furnace condition requires 130 ° C. for 10 minutes or more.

Further, in order to facilitate the existence of a region having a high hardness inside the surface of the elastic member, it is effective to adjust the mixing ratio of the prepolymer and the curing agent as the elastic member. As a specific compounding ratio, it is preferable to mix so that the molar ratio (α value) of the hydroxyl group to the isocyanate group is 0.45 or more and 0.65 or less. As for the state of the elastic member at the time of forming the cured region, it is preferable that more unreacted isocyanate groups are present inside the elastic member. Since the isocyanate groups existing on the surface and inside of the elastic member react with the isocyanate compound which is a material for forming the cured region, when more unreacted isocyanate groups are present inside the elastic member, the inside of the elastic member becomes more. This is because it tends to have high hardness.

Further, even in the above mixing ratio, the amount of residual isocyanate tends to gradually decrease with the passage of time after molding, so that the formation of the cured region is preferably performed within 6 hours after the production of the elastic member. The amount of residual isocyanate can be controlled by the mixing ratio and the time after the production of the elastic member. Regarding the measurement of the amount of residual isocyanate on the surface, for example, it can be measured by infrared absorption spectroscopy (IR), and from the obtained IR spectrum, the NCO peak of isocyanurate (near 2260 cm ^{-1 to} 2270 cm ^-1 ) and The aromatic ring peak of isocyanate (around 1600 cm ^-1 ) is determined, and the ratio (A / B) of the absorbance A of NCO to the absorbance B of the aromatic ring is used as an index of the amount of residual isocyanate. The amount of residual isocyanate is preferably 0.2 or more in the measurement on the surface of the elastic member in order to facilitate the existence of a region having a high hardness inside the surface.

[Material for forming hardened region]
The material for forming the cured region is not particularly limited as long as it can cure the elastic member or can form the cured region on the surface of the elastic member, for example, an isocyanate compound. And acrylic resin. The material forming the cured region may be diluted with a solvent or the like before use. The solvent used for dilution is not particularly limited as long as it dissolves the material to be used, and examples thereof include toluene, xylene, butyl acetate, methyl isobutyl ketone, and methyl ethyl ketone.

When the constituent material of the elastic member is a polyester urethane elastomer, as the material forming the cured region, an isocyanate compound which is a constituent material of the polyester urethane elastomer is used in consideration of compatibility with the elastic member and impregnation property into the elastic member. It is more preferable to use it. As the isocyanate compound to be brought into contact with the elastic member, a compound having one or more isocyanate groups in the molecule can be used. As the isocyanate compound having one isocyanate group in the molecule, an aliphatic monoisocyanate such as octadecyl isocyanate (ODI), an aromatic monoisocyanate such as phenylisocyanate (PHI) and the like can be used. As the isocyanate compound having two isocyanate groups in the molecule, those usually used for producing a polyurethane resin can be used, and specific examples thereof include the following. 2,4-Toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), 4,4'-diphenylmethane diisocyanate (MDI), m-phenylene diisocyanate (MPDI), tetra Methylene diisocyanate (TMDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI) and the like. Further, as an isocyanate compound having three or more isocyanate groups in the molecule, for example, 4,4', 4 "-triphenylmethane triisocyanate, 2,4,4'-biphenyltriisocyanate, 2,4,4'. -Diphenylmethane triisocyanate or the like can be used. Further, as the isocyanate compound having two or more isocyanate groups, a modified derivative thereof, a multimer or the like can also be used. Among them, in order to efficiently increase the hardness of the cured region. MDI having high crystallinity, that is, having a symmetric structure is preferable, and MDI containing a modified product is liquid at room temperature, and is more preferable from the viewpoint of workability.

[Hardness of hardened area]
The hardened region in the vicinity of the free end of the elastic member of the present invention has an internal dynamic hardness larger than the dynamic hardness of the surface of the first surface and / or the second surface. The contact surface of the elastic member that comes into contact with the member to be cleaned needs to be flexible from the viewpoint of stabilizing the contact state with the member to be cleaned. Therefore, the dynamic hardness DHs of the cured surface is 0.1 (mN / μm ² ) or more and 0.4 (mN / μm ² ) or less.

Further, in order to improve the cleaning performance, a cured region having a dynamic hardness higher than the dynamic hardness DHs of the surface is provided inside the vicinity of the surface of the cured region at the tip of the elastic member. Specifically, in the cross section orthogonal to the longitudinal direction of the elastic member, the distance L from the edge on the straight line that bisects the angle of the edge composed of the first surface and the second surface is When the maximum value of the dynamic hardness at each position of 0 μm <L ≦ 100 μm is DHm (mN / μm ² ), DHm is larger than DHs. By having such a configuration, the cleaning blade secures the contact pressure required when it comes into contact with the member to be cleaned, and peaks even if the area (contact width) of the contact portion becomes slightly large. The pressure (contact pressure per unit area of the contact portion (pressure obtained by dividing the contact pressure by the area of the contact portion)) does not easily decrease. As a result, it exhibits excellent cleaning performance.

When the maximum value of dynamic hardness does not exist at a position where the distance L on the straight line is in the range of 0 μm <L ≦ 100 μm, and a portion having a dynamic hardness higher than DHs exists at a position where L exceeds 100 μm. When the cleaning blade comes into contact with the member to be cleaned, the contact width becomes too wide and the peak pressure may not increase.

In the present invention, the measurement position of the dynamic hardness inside the free end of the elastic member is set from the edge formed by the first surface and the second surface in the cross section orthogonal to the longitudinal direction of the elastic member as a starting point. The position is on a straight line that divides the edge angle into two equal parts. The reason is that the measurement surface of the dynamic hardness DHs is at least one surface of the first surface and the second surface, and as shown in FIG. 3, the positional relationship with the member to be cleaned at the time of cleaning is the reason. This is because the direction of the angle can be regarded as the effective thickness direction of the cleaning blade.

If the dynamic hardness DHs of the cured surface is larger than 0.4, the surface hardness is too large, and edge chipping may occur. Further, when the dynamic hardness DHs of the cured surface is less than 0.1, even if the internal hardness in the vicinity of the surface is large, the contact width becomes too wide, the peak pressure decreases, and the cleaning performance may deteriorate. More preferred values for dynamic hardness DHs are in the range 0.12 to 0.35.

It is more preferable that the position showing DHm on the straight line is within the range where the distance L from the edge is 20 μm or more and 100 μm or less. When the position indicating DHm exists within a distance of 20 μm to 100 μm from the edge, the occurrence of edge chipping can be suppressed more effectively. As a more preferable range, the position showing DHm is within a distance of 20 μm to 80 μm from the edge.

Further, when the maximum value of the dynamic hardness on the straight line that divides the angle forming the edge of the cross section orthogonal to the longitudinal direction of the elastic member into two equal parts is DHm and the distance from the edge is Pmax (μm), the dynamic hardness Is even more preferable to gradually increase from the edge to the position of Pmax. This is because if the hardness is gradually increased in this way, there is no region having extremely high hardness at a position between 20 μm from the surface, so that edge chipping is unlikely to occur even during long-term use.

Further, the DHm is preferably 1.1 times or more the dynamic hardness DHs of the cured surface. When the DHm is 1.1 times or more the DHs, the contact pressure on the member to be cleaned can be applied more reliably.

Further, DHm is preferably 10 times or less of DHs. When DHm is 10 times or less of DHs, the hardness of the hardened region inside the contact surface is not too large, so that the rubber elasticity at the tip of the elastic member is not easily impaired. An even more preferable range of DHm is 1.2 times or more and 8 times or less of DHs.

It is more preferable that the cured region is formed on both the first surface and the second surface forming an edge that comes into contact with the member to be cleaned of the elastic member. This is because, as shown in FIG. 3, both the first surface and the second surface may come into contact with the member to be cleaned during cleaning.

[Method of measuring hardness in hardened area]
In the present invention, the hardness of the cured region can be measured by the following method. As the measuring machine, "Shimadzu Dynamic Ultra-Micro Hardness Meter DUH-W211S" manufactured by Shimadzu Corporation can be used. As an indenter, a 115 ° triangular cone indenter is used, and the dynamic hardness can be calculated from the following formula.
Dynamic hardness: DH = α × P / D ²
In the formula, α represents a constant due to the shape of the indenter, P represents the test force (mN), and D represents the amount of indenter penetrating into the sample (pushing depth) (μm).

The measurement conditions are as follows.
α: 3.8584,
P: 1.0 mN,
Load speed: 0.03mN / sec,
Retention time: 5 seconds,
Measurement environment: temperature 23 ° C, relative humidity 55%,
Aging of measurement sample: Leave for 6 hours or more in an environment with a temperature of 23 ° C and a relative humidity of 55%.

The method for preparing the measurement sample is as follows. The measurement sample is 4 mm in the longitudinal direction (2 mm in both directions from the midpoint) from each of the three intermediate points (three points) in the image forming region divided into three equal parts in the longitudinal direction, and the edge 7 to 2 mm in the lateral direction. Cut out to the dimensions of (see FIG. 5).

For the dynamic hardness DHs of the cured surface, the sample is placed so that the indenter vertically hits the cured surface (first surface, second surface) of the cured region of the measurement sample, and the longitudinal direction is 2 mm from the end, short. The manual direction or the thickness direction is measured at a position separated from the edge by 100 μm or more and 500 μm or less. FIG. 6A is a view in which the indenter is arranged so as to vertically hit the second surface of the sample. This measurement is performed on three measurement samples, and the average value is defined as the dynamic hardness DHs ₂ of the surface of the second surface. Similarly, the indenter is arranged so as to vertically hit the first surface of the three measurement samples, and the average value of the three measurement values is defined as the dynamic hardness DHs ₁ of the surface of the first surface. Then, from the dynamic hardness DHs ₁ of the surface of the first surface and the dynamic hardness DHs ₂ of the surface of the second surface, a higher value is defined as the dynamic hardness DHs (mN / μm ² ) of the cured surface.

The measurement of the dynamic hardness inside the vicinity of the surface of the cured region at the tip of the elastic member within the cross section orthogonal to the longitudinal direction of the elastic member is performed by the following procedure. Each sample after the above measurement is cut at a position of 2 mm in the longitudinal direction, and the samples are arranged so that the indenter vertically hits the cut surface (see FIG. 6B). The measurement position is on a straight line that bisects the angle of the edge, and the distance L from the edge is set at an interval of 10 μm (see FIG. 7). The measurement is sequentially performed at each of these positions, and the measured value is measured up to the point where the dynamic hardness of the elastic member in which the cured region is not formed becomes. This measurement is performed on three measurement samples, and the average value thereof is taken as the dynamic hardness inside the free end. Then, the maximum value of these measured values of dynamic hardness is DHm (mN / μm ² ).

[Manufacturing method of cleaning blade]
[Manufacturing of cleaning blade precursor]
The method for producing the cleaning blade according to the present invention is not particularly limited as long as a suitable method may be selected from known methods. Further, as a method for manufacturing the elastic member, a suitable one may be selected from known methods such as a mold molding method and a centrifugal molding method. For example, in a cleaning blade mold provided with a cavity for forming an elastic member, a support member coated with an adhesive on a contact portion with the elastic member is arranged. On the other hand, a prepolymer in which polyisocyanate and a polyol are partially polymerized, and a curing agent containing a polyol, a chain extender, a catalyst, and other additives are put into a casting machine, and mixed and stirred at a constant ratio in a mixing chamber. Then, a raw material composition such as a polyurethane elastomer is obtained. This raw material composition is injected into the mold to form a cured molded product (elastic member) on the adhesive-coated surface of the support member, and the mold is removed after reaction curing. If necessary, a cleaning blade precursor in which the support member and the elastic member are integrally formed by appropriately cutting the elastic member in order to secure a predetermined size and the edge dimensional accuracy of the contact portion of the elastic member is obtained. Can be manufactured.

When the elastic member is manufactured by a centrifugal molding machine, a prepolymer obtained by partially polymerizing polyisocyanate and a polyol and a curing agent containing a polyol, a chain extender, a catalyst, and other additives are mixed and stirred. A raw material composition such as a polyurethane elastomer is put into a rotating drum to obtain a polyurethane elastomer sheet. This polyurethane elastomer sheet is cut to ensure predetermined dimensions and edge dimensional accuracy of the abutting portion of the elastic member. The polyurethane elastomer sheet (elastic member) thus obtained can be attached to a support member coated with an adhesive to produce a cleaning blade precursor.

[Formation of hardened area]
The formation of the cured region can be performed by the method already described. That is, first, a material for forming a cured region is applied to the first surface, the second surface, and the like of the tip of the elastic member of the cleaning blade precursor. Next, the tip of the elastic member is heat-treated at, for example, at a temperature of 80 ° C. or higher for 3 minutes or longer. As a result, a cured region can be formed on the surface and inside of the tip of the elastic member.

When it is necessary to cut the elastic member in order to form an edge for contacting the member to be cleaned on the cleaning blade, the hardened region may be formed before or after the cutting. In the case of centrifugal molding, a cured region can be formed before being joined to the support member. As described above, the cleaning blade can be obtained.

<Process cartridge and electrophotographic image forming device>
The cleaning blade according to the present invention can be used by being incorporated into a process cartridge for an electrophotographic image forming apparatus, or can be used by being incorporated into an electrophotographic image forming apparatus.

The present invention will be described below with reference to Production Examples, Examples and Comparative Examples, but the present invention is not limited to these Examples. Reagents or industrial chemicals were used as raw materials other than those shown in Examples and Comparative Examples.

[Example 1]
In this example, the integrally molded type cleaning blade shown in FIG. 1 was manufactured and evaluated.

1. 1. Support member A galvanized steel sheet with a thickness of 1.6 mm was prepared and processed to obtain a support member having an L-shaped cross section shown by reference numeral 3 in FIG. An adhesive for bonding polyurethane resin (trade name: Chemlock 219, manufactured by Lord Corporation) was applied to a portion of the support member where the elastic member contacts.

2. 2. Preparation of Raw Materials for Elastic Members The materials of the type and amount shown in the column of component 1 in Table 1 were reacted at 80 ° C. for 3 hours with stirring to obtain a prepolymer having a molar concentration of isocyanate of 8.50%. A polyurethane elastomer having a molar ratio (α value) of 0.60 of hydroxyl groups to isocyanate groups is mixed with 1000 g of this prepolymer by mixing 212.9 g of a curing agent consisting of the types and amounts of materials shown in the column of component 2 in Table 1. A composition was prepared and used as a raw material for an elastic member.

3. 3. Integral molding of support member and elastic member The polyurethane elastomer composition is injected into a molding die for cleaning blades arranged so that the adhesive application portion of the support member protrudes into the cavity, and cured at 130 ° C. for 2 minutes. After that, the mold was removed to obtain an integrally molded body of the elastic member and the support member.

This integrally molded body is appropriately cut before forming the cured region, and the distances of the edge angle of 90 degrees, the lateral direction (lower surface 5), the thickness direction (elevation 6), and the longitudinal direction of the elastic member are 7.5 mm, respectively. It was set to 1.8 mm and 240 mm.

4. Formation of hardened region Modified MDI (trade name: Millionate MTL, manufactured by Tosoh Corporation) was prepared as a material for forming the hardened region. The material for forming the cured region is heated to 80 ° C., and the integrally molded body is immersed in the material so that the other five surfaces except the surface facing the support member (reference numeral 11 in FIG. 2) are immersed in the material. The elastic member was immersed for 20 seconds to coat each surface with the material. Then, the material for forming a cured region on the surface of the elastic member was wiped off with a sponge soaked with butyl acetate as a solvent. Next, a heat treatment was performed in an electric furnace at a temperature of 130 ° C. for 40 minutes so that the material for forming a cured region impregnated in the elastic member was further diffused and cured inside the elastic member. In this way, hardened regions were formed on the five surfaces of the elastic member (first surface, second surface, surface facing the first surface, both end surfaces in the longitudinal direction) and inside under those surfaces. A cleaning blade 1 was obtained. The cured region was formed 1 hour after molding the elastic member.

The obtained cleaning blade was evaluated by the following method. The results of each evaluation are shown in Table 4.

<1. Hardness measurement of hardened area>
The hardness was measured on the first surface and the second surface by the hardness measuring method of the cured region, and the dynamic hardness DHs was determined. Moreover, the maximum value DHm of the dynamic hardness was measured.

<2. Evaluation of cleaning performance>
The cleaning blade 1 was incorporated into a black cartridge of a color laser beam printer (trade name: HP LaserJet Enterprise Color M553dn, manufactured by Hewlett-Packard Co., Ltd.) as a cleaning blade for a photosensitive drum to be cleaned. Next, 12,500 images, which is the number of printable sheets, were formed in a low temperature and low humidity environment (temperature 15 ° C., relative humidity 10%) (hereinafter, referred to as "normal evaluation"). Further, the developing machine was replaced with a new black cartridge developing machine, and 12,500 images, which is the number of printable sheets, were formed again (hereinafter, referred to as "double evaluation"). In addition, the waste toner was evaluated by making a hole in the back surface of the cartridge and sucking it out at appropriate times. The performance of the obtained images was ranked according to the following evaluation criteria.
A: Image defects (streaks on the image) caused by the cleaning blade do not occur in either the normal evaluation or the double evaluation.
B: Image defects (streaks on the image) caused by the cleaning blade do not occur in the normal evaluation, but occur slightly in the double evaluation, but there is no problem in actual use.
C: Image defects (streaks on the image) caused by the cleaning blade do not occur in the normal evaluation, but occur in the double evaluation.
D: Image defects (streaks on the image) caused by the cleaning blade occur slightly in both the normal evaluation and the double evaluation, but there is no problem in actual use.
E: Image defects (streaks on the image) caused by the cleaning blade occur in both normal evaluation and double evaluation.

<3. Cleaning blade edge chipping evaluation>
After the above cleaning performance evaluation is completed (double evaluation), the cleaning blade is removed from the cartridge and magnified 1000 times with a digital microscope (trade name: main body VHX-5000, lens VH-ZST, manufactured by KEYENCE). Observation was made. The tip of the first surface (lower surface 5) of the elastic member of the cleaning blade was used as the observation surface, and as shown in FIG. 8, the support member was tilted at an angle of 45 ° so as to be upward and the tip of the elastic member was downward. It was installed at the position and the whole area in the longitudinal direction was observed. As shown in the partially enlarged view of FIG. 8, the maximum value of the distance of the edge chipped portion in the lateral direction was measured as the “edge chipped amount”, and the performance was ranked according to the following evaluation criteria.
A: Edge chipping does not occur.
B: The amount of edge chipping is less than 2 μm.
C: The amount of edge chipping is 2 μm or more and less than 5 μm.
D: The amount of edge chipping is 5 μm or more.

<4, Comprehensive evaluation>
Based on the rank of the image evaluation of the cleaning performance and the rank of the evaluation result of the edge chipping evaluation of the cleaning blade, the comprehensive evaluation was performed as follows.
A: The evaluation result is A / A, A / B, or a combination of B / A.
B: The evaluation result is a combination of A / C, C / A, B / B, B / C, or C / B.
C: The evaluation result is a combination of C / C.
D: There is no E in the evaluation result, but there is one or more Ds.
E: There is one or more E in the evaluation result.

<5. Evaluation of turning over the cleaning blade (reference)>
In the above evaluation of cleaning performance, no turning or abnormal noise was generated, but as a reference, the turning evaluation of the cleaning blade under a harsher environment than normal use was carried out as follows.

The cleaning blade of this example is incorporated as a cleaning blade for a photosensitive drum, which is a member to be cleaned, in a new black cartridge that is different from the evaluation of cleaning performance, and is used in a high temperature and high humidity environment (temperature 30 ° C, relative humidity 80%). Below, 10,000 images were formed. After that, the cartridge from which the developing machine was removed was set in an idle rotating machine (a device equipped with a jig for holding the cartridge while rotating the photosensitive drum). In the same environment, the photosensitive drum was rotated idle at 170 rpm, and the state of the tip of the cleaning blade was observed for 10 minutes. The tip of the cleaning blade was observed by processing the cartridge and installing a CCD camera or the like. Performance was ranked according to the following evaluation criteria.
A: No turning or abnormal noise (chattering noise) occurs.
B: No turning is generated, but abnormal noise (chattering noise) is generated.
C: Turns occur.

[Examples 2-7, 10-12 and 15-16]
Same as in Example 1 except that the temperature, immersion time, heating conditions (temperature / time), and elapsed time after molding of the elastic member in the formation of the cured region were changed to the conditions shown in Table 2. Then, cleaning blades 2 to 7, 10 to 12 and 15 to 16 in which a cured region was formed on the five surfaces of the elastic member and the inside under these surfaces were obtained. The evaluation results are shown in Table 4.

[Example 8]
The temperature, immersion time, and heating conditions (temperature / time) of the material for forming the cured region in the formation of the cured region were changed to the conditions shown in Table 2. Further, in forming the cured region, the immersion surfaces were set to four surfaces (contact surface, top surface, and both end surfaces in the longitudinal direction). Other than these, in the same manner as in Example 1, a cleaning blade 8 having a cured region on these four surfaces and under the surfaces thereof was obtained. The evaluation results are shown in Table 4.

[Example 9]
In the formation of the cured region, the integrally molded body was formed in the same manner as in Example 1 except that the temperature, immersion time, and heating conditions (temperature / time) of the material for forming the cured region were changed to the conditions shown in Table 2. Hardened areas were formed on the five surfaces and within these surfaces. Next, the integrally molded body is cooled, both ends of the elastic member are cut so that the distance in the longitudinal direction is 240 mm, and the three surfaces (first surface, second surface, and first surface are opposed to each other). A cleaning blade 9 having a surface) and a cured region under the surface thereof was obtained. The evaluation results are shown in Table 4.

[Example 13]
An integrally molded body of a support member and an elastic member was manufactured in the same manner as in Example 1. The same material for forming a cured region as in Example 1 was heated to 70 ° C., the spray discharge amount was set to 20 mg in 2 seconds, and the lower surface of the tip of the elastic member (a region having a distance of 3 mm from the edge in the Z direction, the first Spray coating was performed on one surface) while moving the elastic member at 50 mm / s. Next, the integrally molded body was left to stand in an environment having a temperature of 25 ° C. and a relative humidity of 50% for 10 minutes, and then heat-treated in an electric furnace at a temperature of 180 ° C. for 3 minutes. Next, cooling was performed, and the elastic member was cut so that the lateral direction and the longitudinal direction had predetermined dimensions to obtain a cleaning blade 13. The hardened region is formed on only one surface of the lower surface (first surface) of the elastic member. The evaluation results are shown in Table 4.

[Example 14]
An integrally molded body of a support member and an elastic member was manufactured in the same manner as in Example 1. Next, before forming the cured region, the elastic member was cut so that the lateral direction was a predetermined size. Next, the same material for forming the cured region as in Example 1 was heated to 80 ° C., the coating amount was set to 18 mg with 20 drops, and a dispenser was used to apply the material to the elevation (second surface) of the elastic member. The elastic member was applied while moving at 100 mm / s. Next, the integrally molded body was left to stand in an environment having a temperature of 25 ° C. and a relative humidity of 50% for 10 minutes, and then heat-treated in an electric furnace at a temperature of 130 ° C. for 30 minutes. Next, cooling was performed, and the elastic member was cut so that the distance in the longitudinal direction was 240 mm to obtain a cleaning blade 14. The formation of the cured region is only one surface of the elevation surface (second surface) of the elastic member. The evaluation results are shown in Table 4. Table 3 shows the differences in the manufacturing conditions between Examples 13 and 14.

[Comparative Example 1]
This comparative example is an example in which a hardened region is not formed on the elastic member. An integrally molded body of a support member and an elastic member was manufactured in the same manner as in Example 1. Next, the elastic member was cut so that the lateral direction was 7.5 mm and the longitudinal direction was 240 mm to obtain a cleaning blade 21. The evaluation results are shown in Table 4.

[Comparative Examples 2 and 3]
Same as in Example 1 except that the temperature, immersion time, heating conditions (temperature / time), and elapsed time after molding of the elastic member in the formation of the cured region were changed to the conditions shown in Table 2. Then, the cleaning blades 22 and 23 in which the five surfaces of the elastic member and the cured region were formed inside these surfaces were obtained. The evaluation results are shown in Table 4.

[Comparative Example 4]
The temperature and immersion time of the material for forming the cured region in the formation of the cured region were changed to the conditions shown in Table 2. No heat treatment was performed. Except for these, in the same manner as in Example 1, a cleaning blade 24 having five surfaces of the elastic member and a cured region formed inside under the surfaces thereof was obtained. A cured region was formed 24 hours after the elastic member was molded. The evaluation results are shown in Table 4.

In Examples 1 to 14, the dynamic hardness DHs on the surface of the cured region satisfies the condition of the formula (1), and the maximum value DHm of the dynamic hardness inside the free end satisfies the condition of the formula (2). Therefore, the contact pressure required for cleaning the surface of the member to be cleaned is secured, thereby maintaining the cleaning performance, and the edge chipping at the tip of the cleaning blade is reduced even after long-term use. Results were obtained. Among them, Examples 1, 8, 15 and 16 were better.
In Examples 1 to 12, the cured region is formed on both the first surface and the second surface forming the edge to be abutted against the member to be cleaned of the elastic member, so that the tip at the time of cleaning is formed. The behavior of the part was stable, and the result with better cleanability was obtained.
In Examples 1 to 11, since the DHm is 10 times or less of the DHs, the hardness of the cured region inside the contact surface is not too large, so that the rubber elasticity at the tip of the elastic member is not easily impaired, and the cover is covered. The followability with the cleaning member was improved, and the result of better cleaning property was obtained.
In Examples 1 to 10, since the dynamic hardness gradually increases from the edge to the position showing the DHm, there is no region having an extremely high hardness between the edge and the position showing the DHm, and the period is longer. The result was that edge chipping was less likely to occur even during use.
In Examples 1 to 8 and 10 to 12, since both end faces in the longitudinal direction have a cured surface, the rigidity of both ends can be improved, and the result that the turning of the cleaning blade can be further reduced can be obtained. Was done.

1 Cleaning blade 2 Elastic member 3 Support member 4 Tip 5 Lower surface of elastic member 6 Elevation of elastic member 7 Edge 8 Cleaned member 9 End X Longitudinal direction Y Thickness direction Z Short direction R Rotation direction of the member to be cleaned

Claims (9)

A cleaning blade including an elastic member and a support member that supports the elastic member.
The free end portion of the elastic member has an edge and a first surface and a second surface constituting the edge.
One or both of the first surface and the second surface has a cured surface and
The dynamic hardness of the cured surface was defined as DHs (mN / μm ² ).
Within the cross section orthogonal to the longitudinal direction of the elastic member, the maximum value of the dynamic hardness at each position where the distance L from the edge on the straight line that bisects the angle of the edge is 0 μm <L ≦ 100 μm. When is DHm (mN / μm ² )
Cleaning blades that satisfy the relationships represented by the following equations (1) and (2):
Equation (1) 0.1 ≤ DHs ≤ 0.4
Equation (2) DHs <DHm. The cleaning blade according to claim 1, wherein the position showing the maximum value of the dynamic hardness at each position on the straight line is at a distance of 20 μm or more and 100 μm or less from the edge. The cleaning blade according to claim 1 or 2, wherein the dynamic hardness on the straight line gradually increases from the edge to the position indicating the DHm. The cleaning blade according to any one of claims 1 to 3, wherein the DHm is 1.1 times or more the DHs. The cleaning blade according to any one of claims 1 to 4, wherein the DHm is 10 times or less the DHs. The cleaning blade according to any one of claims 1 to 5, wherein both end faces in the longitudinal direction of the elastic member have a cured surface. The cleaning blade according to any one of claims 1 to 6, wherein the cured surface is present on both the first surface and the second surface. A process cartridge having the cleaning blade according to any one of claims 1 to 7. An electrophotographic image forming apparatus having the cleaning blade according to any one of claims 1 to 7.

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