Electrophotographic blade, process cartridge and electrophotographic image forming apparatus

Abstract

To provide a blade for electrophotography that contributes to stable formation of a high-quality electrophotographic image, a process cartridge that can contribute to stable formation of a high-quality electrophotographic image, and an electrophotographic image forming apparatus that can stably form a high-quality electrophotographic image.SOLUTION: A blade for electrophotography is brought into contact with a contact target member, and has a leaf spring material and a resin layer that covers at least part of a surface of the leaf spring material with the resin layer to form at least a contact part with the contact target member. When a portion on one end of the leaf spring material is fixed such that the length (L) from a fixed end to the other end becomes 5 mm or more and 20 mm or less, a force required to displace the other end by 1 mm is 5 N / m or more and 100 N / m or less. In the resin layer, (1) the thickness of the resin layer is 0.05 mm or more and 2.00 mm or less; (2) the value of tanδ at 5°C to 40°C of the resin layer is 0.05 or more and 0.70 or less; (3) the modulus of elasticity of the resin layer is 1.0 to 60.0 MPa or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an electrophotographic blade, a process cartridge for use in an electrophotographic image forming apparatus, and an electrophotographic image forming apparatus. [Background technology]

[0002] In electrophotographic image formation, an electrophotographic blade is used as a means for restricting the thickness of the layer of developer (hereinafter also referred to as "toner") carried and conveyed by a developer carrier to an image carrier to a thin layer. The electrophotographic blade is brought into contact with the developer carrier, and the toner passes through the contact area to regulate the toner layer thickness. Such an electrophotographic blade has a resin layer that is pressed against the developer carrier and a leaf spring material for pressing the blade against the developer carrier with a predetermined pressure. The electrophotographic blade having the above-mentioned configuration can be easily pressed against the developer carrier with a uniform pressure over its entire length. Patent Document 1 discloses an electrophotographic blade made of a leaf spring material and a resin layer, in which a thermoplastic polyester elastomer is used as the resin layer. In recent years, there has been a demand for high speed, high durability, and high image quality for electrophotographic devices, but in printers with medium or higher speeds, vibrations within the electrophotographic image forming device and vibrations of the developer carrier increase. These vibrations may cause the contact portion of the electrophotographic blade against the developer carrier to vibrate, making the contact state unstable. As a result, the layer thickness of the developer on the developer carrier becomes non-uniform, and an electrophotographic image with horizontal stripe-like uneven density (hereinafter also referred to as a "banding image") may occur. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication 2008-00160 Summary of the Invention [Problem to be solved by the invention]

[0004] One aspect of the present disclosure is directed to providing an electrophotographic blade that contributes to the stable formation of high-quality electrophotographic images. Another aspect of the present disclosure is directed to providing a process cartridge that can contribute to the stable formation of high-quality electrophotographic images. Still another aspect of the present disclosure is directed to providing an electrophotographic image forming apparatus that can stably form high-quality electrophotographic images. [Means for solving the problem]

[0005] According to one aspect of the present disclosure , electric A blade for a child photograph, The electrophotographic blade is a developer amount regulating blade that is brought into contact with a developer carrying member, The electrophotographic blade comprises: Leaf spring material and 、 At least a portion of the surface of the leaf spring material is coated, Developer Carrier A resin layer that constitutes the contact portion with 、 having When the leaf spring material is fixed at one end thereof such that the length (L) from the fixed end to the other end is 5 mm to 20 mm, the force required to displace the other end by 1 mm is 5 N / m or more and 100 N / m or less, The resin layer satisfies the following requirements (1) to (3): 、 An electrophotographic blade characterized by: Requirement (1) The thickness of the resin layer is 、 0.05mm or more and 2.00mm or less, Requirement (2) Measured at a frequency of 10Hz The tan δ value of the resin layer at 5°C to 40°C is 、 0.05 or more and 0.70 or less, Requirement (3) Resin layer storage Elastic modulus 、 The pressure is 1.0 MPa or more and 60.0 MPa or less.

[0006] According to another aspect of the present disclosure, A developer carrier; a developer amount regulating blade in contact with the developer carrying member; An electrophotographic image forming apparatus comprising: The developer amount regulating blade is the above-mentioned electrophotographic blade. An electrophotographic imaging apparatus is provided. Further, according to another aspect of the present disclosure, current an image carrier; a developer amount regulating blade in contact with the developer carrying member; A process cartridge detachably mountable to a main body of an electrophotographic image forming apparatus, comprising: The developer amount regulating blade is the above-mentioned electrophotographic blade. A process cartridge is provided. Effect of the Invention

[0007] According to one aspect of the present disclosure, it is possible to obtain an electrophotographic blade that can maintain a stable contact state even when a contacted member such as a developer carrier is vibrated, and contributes to the stable formation of high-quality electrophotographic images. According to another aspect of the present disclosure, it is possible to obtain a process cartridge and an electrophotographic image forming apparatus that can provide stable electrophotographic images. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is an explanatory diagram of an electrophotographic blade according to one embodiment of the present disclosure. [Diagram 2] 2 is a diagram showing an example of a state in which the blade shown in FIG. 1 is in contact with the surface of a developer carrier. FIG. [Diagram 3] 3(a) to 3(c) are diagrams showing examples of the blade different from that shown in FIG. [Figure 4] FIG. 1 is a diagram showing an example of an apparatus for manufacturing an electrophotographic blade according to an embodiment of the present disclosure. [Diagram 5] FIG. 2 is a schematic cross-sectional view of a molding drum of an example of an apparatus for manufacturing an electrophotographic blade according to an embodiment of the present disclosure. [Figure 6] 2 illustrates an example of a developing device according to an embodiment of the present disclosure. [Figure 7] 2 is an example of a process cartridge according to an aspect of the present disclosure. [Figure 8] 1 illustrates an example of an image forming apparatus according to an aspect of the present disclosure. [Figure 9]FIG. 2 is a schematic diagram of an apparatus for measuring vibration damping properties of an electrophotographic image forming blade. [Figure 10] FIG. 1 is a diagram showing an example of an apparatus for manufacturing an electrophotographic blade according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] One aspect of the present disclosure is , electric A blade for a child photograph, The electrophotographic blade is a developer amount regulating blade that is brought into contact with a developer carrying member, and the electrophotographic blade is A leaf spring material and at least a part of the surface of the leaf spring material are covered, Developer Carrier and a resin layer that constitutes a contact portion between the plate spring material and the plate spring. When a portion on one end side of the plate spring material is fixed so that the length (L) from the fixed end to the other end is 5 mm or more and 20 mm or less, the force required to displace the other end by 1 mm is 5 N / m or more and 100 N / m or less. Furthermore, the resin layer satisfies the following requirements (1) to (3). Requirement (1) The thickness of the resin layer is 0.05 mm or more and 2.00 mm or less. Requirement (2) Measured at a frequency of 10Hz The resin layer has a tan δ value of 0.05 or more and 0.70 or less at 5° C. or more and 40° C. or less. Requirement (3) Resin layer storage The elastic modulus is 1.0 MPa or more and 60.0 MPa or less. Hereinafter, the present disclosure will be described in detail with reference to the case where the present disclosure is used as an electrophotographic blade. Note that the embodiments of the present disclosure are for explaining the present disclosure, but the present disclosure is not limited to these embodiments.

[0010] [Configuration of Developer Amount Regulating Blade] FIG. 1 shows a schematic cross-sectional view of an example of an electrophotographic blade according to one embodiment of the present disclosure. The electrophotographic blade 2 has at least a leaf spring material 4 and a resin layer 3, and the resin layer 3 constitutes an abutment portion that abuts against a contacted member 1 such as a developer carrier. The leaf spring material 4 is fixed to a support member 44 at one end. When the fixed end 41 is the position closest to the other end 42 of the fixed portion 400 of the leaf spring material 4 to the support member 44, the length from the fixed end 41 to the other end 42, which is the free end, is defined as the length L. The thickness of the resin layer 3 is defined as the thickest part based on the surface of the resin layer 3 facing the leaf spring material 4. As shown in FIG. 2, the electrophotographic blade 2 has the leaf spring material 4 fixed to the support member 44, and the other end 42 abuts against the surface of the contacted member 1 (developer carrier) with the fixed point 40 as a fulcrum.

[0011] [Resin Layer] The resin layer 3 is (1) Its thickness is 0.05 mm or more and 2.00 mm or less, (2) Measured at a frequency of 10Hz. The value of tan δ over the entire temperature range of 5 to 40°C is 0.05 to 0.70, and (3) Over the entire temperature range of 5 to 40°C storage The elastic modulus is 1.0 MPa or more and 60.0 MPa or less. The present inventors have found that by optimizing the thickness of the resin layer and the elastic modulus and tan δ of the resin layer at the actual use temperature, it is possible to prevent the thickness of the toner layer on the developer carrier from becoming non-uniform, even when the developer carrier is vibrated. In order to suppress the non-uniformity of the toner layer thickness, for example, it is effective to achieve both a high level of reduction in the initial amplitude of vibration caused by the developing roller and early attenuation of the vibration.

[0012] <tanδ> Adjusting the tan δ of the resin layer is effective for early damping of vibrations transmitted to the electrophotographic blade. Tan δ is the value obtained by dividing the loss modulus E" by the storage modulus E' in a polymer compound that is a viscoelastic body, and is a parameter that indicates the ability of a viscoelastic body to lose energy as heat when it deforms. The lower limit of tan δ of the elastic layer is 0.05 or more, preferably 0.10 or more, in the temperature range of 5° C. to 40° C., which is the actual use environment. This allows the vibration caused by the developing member to be efficiently lost as heat energy by deformation of the elastic layer. The upper limit of tan δ is 0.70 or less, preferably 0.50 or less, and particularly preferably 0.30 or less, in order to prevent the time it takes for the deformed resin to return to its original shape from becoming longer and the thickness of the toner layer from becoming non-uniform.

[0013] <Storage modulus E' (elastic modulus)> In order to reduce the initial amplitude, it is effective to use a resin layer with a small storage elastic modulus E' (hereinafter also simply referred to as "elastic modulus"). Specifically, in the temperature range of 5 to 40°C, which is the actual usage environment, the initial amplitude of vibration transmitted to the developing blade can be reduced by setting the elastic modulus to 60.0 MPa or less, preferably 50.0 MPa or less, and particularly 15.0 MPa or less. The lower limit of the elastic modulus is 1.0 MPa or more, preferably 2.0 MPa or more, and particularly 5.0 MPa or more, from the viewpoint of preventing unevenness in the contact pressure of the electrophotographic blade against the developer carrier.

[0014] <Thickness of resin layer> The thickness of the resin layer is 0.05 mm or more, more preferably 0.10 mm or more. The resin layer has a thickness of 0.05 mm or more, so that the amount of resin capable of absorbing vibrations can be sufficiently secured, and the vibrations can be efficiently converted into thermal energy. As a result, this contributes to the achievement of early attenuation of the vibrations caused by the developing member. On the other hand, the upper limit of the thickness of the resin layer is 2.00 mm or less, more preferably 1.00 mm or less. By making the thickness of the resin layer 2.00 mm or less, the regulating force of the toner layer on the surface of the developing member by the electrophotographic blade can be made more uniform, and the thickness of the toner layer can be made uniform. As a result, the occurrence of image unevenness caused by the non-uniformity of the thickness of the toner layer can be prevented. In an electrophotographic blade that satisfies all of the above three requirements, the resin layer can quickly absorb vibrations of the developer carrier, and the occurrence of banding in an electrophotographic image can be prevented. In addition, the electrophotographic blade can make the thickness of the toner layer on the surface of the developing roller more uniform, and therefore can prevent the occurrence of uneven density and streaks in an electrophotographic image.

[0015] <Constituent materials of resin layer> The type of resin used in the resin layer is not particularly limited, but it is preferable to use a thermosetting urethane elastomer. A resin with a large tan δ converts vibrations into thermal energy, but as the resin temperature increases, tan δ decreases. For this reason, it is necessary to quickly dissipate the converted heat. Since thermosetting urethane elastomers have high thermal conductivity, they can efficiently dissipate the heat converted from vibration energy. The thermosetting urethane elastomer is obtained from a urethane raw material containing at least a polyisocyanate and a polyol. As the thermosetting urethane elastomer, a thermosetting urethane elastomer obtained by reacting a polyol containing at least one of a polyether polyol or a polyester polyol with 4,4'-diphenylmethane diisocyanate is preferable. These raw materials are described in detail below.

[0016] (Polyisocyanate) Examples of polyisocyanates include the following: 4,4'-diphenylmethane diisocyanate (MDI), 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), xylene diisocyanate (XDI), 1,5-naphthylene diisocyanate (1,5-NDI), p-phenylene diisocyanate (PPDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), tetramethylxylene diisocyanate (TMXDI), carbodiimide-modified MDI, and polymethylene phenyl polyisocyanate (PAPI). Among these, MDI is preferred because it can give polyurethane elastomers with excellent mechanical properties.

[0017] (Polyol) Examples of polyols include the following: polyester polyols such as polyethylene adipate polyol, polybutylene adipate polyol, polyhexylene adipate polyol, (polyethylene / polypropylene) adipate polyol, (polyethylene / polybutylene) adipate polyol, and (polyethylene / polyneopentylene) adipate polyol; polycaprolactone-based polyols obtained by ring-opening polymerization of caprolactone; polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol; and polycarbonate polyols. These can be used alone or in combination of two or more. In addition, acrylic polyols obtained by polymerizing acrylic acid esters or methacrylic acid esters with the above polyols, and polyols obtained by chemically modifying a portion of silicone such as polydimethylsiloxane with multiple hydroxyl groups can also be used. The thermal conductivity of thermosetting urethane elastomers is greatly affected by the type of polyol. Thermal conduction in resins that do not have free electrons is carried out by phonons, which are quantized lattice vibrations, and increasing the mean free path of phonons increases thermal conductivity. The crystalline parts of the resin have high lattice vibration harmonicity, so phonon scattering is less likely to occur. Therefore, it is preferable to select a polyol with high crystallinity in order to increase thermal conductivity. Among these, polyester polyols and polyether polyols, which have high crystallinity, are preferred. Among them, polyether polyol is preferable, and polytetramethylene ether glycol is more preferable. Also, when the average molecular weight is large, the hard part (hard segment) formed by polyisocyanate and the soft part (soft segment) formed by polyol tend to be localized, and phonon scattering occurs at the interface, resulting in a low thermal conductivity. For this reason, the average molecular weight of the polyol is preferably 2000 or less, more preferably 380 or more and 1600 or less. That is, the most preferable polyol is polytetramethylene glycol (PTMG) with an average molecular weight of 650 or more to 1000 or less. Therefore, the thermosetting urethane elastomer according to one embodiment of the present disclosure preferably has a structure represented by the following formula (1) between two adjacent urethane bonds. -[(CH2) n O]m- (1) In formula (1), n ​​is an integer of 2 or more, and m is an integer of 1 or more, provided that n+m is a number necessary for the average molecular weight of the alkylene oxide structure portion in formula (1) in the thermosetting urethane elastomer to be 380 to 1600. The thermosetting urethane elastomer preferably contains the polyether polyol in a proportion of 50 wt% or more and 80 wt% or less. If the proportion of the polyether polyol is 50 wt% or more, the required crystallinity can be obtained, and if the proportion is 80 wt% or less, the required elastic modulus can be obtained. That is, the thermosetting urethane elastomer according to one embodiment of the present disclosure contains a component (polyol) represented by formula (2) as a hydrolyzate, and the proportion of the component relative to the hydrolyzate is preferably 50 to 80 wt%. HO-[(CH2)nO]mH (2) In formula (2), n is an integer of 2 or more, and m is an integer of 1 or more, provided that n+m is a number necessary for the average molecular weight of the alkylene oxide structure portion in formula (1) in the thermosetting urethane elastomer to be 380 to 1600. In the present disclosure, the molecular weight of the polyether polyol refers to a value obtained by measuring the average molecular weight of the hydrolyzate described in the Examples described later.

[0018] (Chain extender) The chain extender added to the urethane raw material as required is not particularly limited as long as it has a molecular weight of 200 or less and can extend the polyurethane elastomer chain, 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), and triethylene glycol. In addition to the above glycols, other polyhydric alcohols can also be used, such as trimethylolpropane, glycerin, pentaerythritol, and sorbitol. These can be used alone or in combination of two or more. It is preferable to use a small amount of chain extender. Polyisocyanate tends to be concentrated around the chain extender, and hardness increases locally. When the amount of chain extender increases, many places with clearly different hardness are present, and phonon scattering occurs at the interface, resulting in a decrease in thermal conductivity. Therefore, from the viewpoint of improving thermal conductivity, it is preferable not to use a chain extender. However, from the viewpoint of improving productivity, it is preferable to add a small amount of chain extender because adding an appropriate amount of chain extender is expected to improve the curing speed, and the amount added in this case is preferably 0.25 mmol / g or less, particularly 0.0 mmol / g. That is, in the thermosetting urethane elastomer according to one embodiment of the present disclosure, the content of alcohol having a molecular weight of 200 or less in the hydrolyzate is preferably 0.25 mmol / g or less, particularly 0.0 mmol / g, relative to the hydrolyzate.

[0019] (catalyst) As the catalyst that may be added to the urethane raw material, a catalyst generally used for curing polyurethane elastomers can be used, for example, a tertiary amine catalyst can be mentioned, specifically, the following can be exemplified. Amino alcohols such as dimethylethanolamine, N,N,N'-trimethylaminopropylethanolamine, and N,N-dimethylaminohexanol; trialkylamines such as triethylamine; tetraalkyldiamines such as N,N,N'N'-tetramethyl-1,3-butanediamine; triethylenediamine, piperazine compounds, and triazine compounds. In addition, organic acid salts of alkali metals such as potassium acetate and potassium octylate can also be used. Furthermore, metal catalysts that are usually used for urethane formation, such as dibutyltin dilaurate, can also be used. These can be used alone or in combination of two or more.

[0020] Other materials that may be added to the urethane raw material include additives such as pigments, plasticizers, waterproofing agents, antioxidants, UV absorbers, light stabilizers, etc. These additives can be blended into the raw material composition as necessary.

[0021] [Leaf spring material] The leaf spring material is a member that generates a contact pressure of the electrophotographic blade against the developer carrier. In other words, by adjusting the rigidity of the leaf spring material, the electrophotographic blade can be brought into contact with the developer carrier with a more appropriate pressure. As a result, the thickness of the toner layer on the developer carrier can be better controlled. Therefore, when one end of the leaf spring material is fixed so that the length (L) from the fixed end to the other end is 5 mm to 20 mm, the force required to displace the other end by 1 mm is 5 N / m to 100 N / m. By making the force 5 N / m or more, the electrophotographic blade can be given sufficient springiness to apply an appropriate contact pressure to the developer carrier. The force is preferably 10 N / m or more. Furthermore, by making the force 100 N / m or less, excessive stress can be prevented from being applied to the toner on the developer carrier. The leaf spring material is preferably made of metal or resin. As the metal, a surface-treated steel plate with chromate treatment and lubricating resin, stainless steel (e.g., SUS304, etc.), phosphorus, bronze, aluminum, etc. can be used. Among them, stainless steel is more preferable because it can be brought into contact with the developer carrier with an appropriate contact pressure. The resin may be a thermosetting resin such as an acrylic resin, a polyethylene resin, a polyester resin, etc. If the leaf spring material is required to have electrical conductivity, a conductive material may be added to the resin. Examples of the conductive agent include ionic conductive agents and electronic conductive agents such as carbon black. The thickness of the leaf spring material is not particularly limited, but is preferably 0.05 mm or more and 0.15 mm or less. By setting the thickness of the leaf spring material to 0.05 mm or more and 0.15 mm or less, the leaf spring material can have an appropriate leaf spring property. In addition, as shown in FIG. 1, the leaf spring material is preferably fixed so that the length (L) from the fixed end 41 to the other end 42 of the leaf spring material 4 is 5 mm or more and 20 mm or less. By fixing the leaf spring so that the length (L) is 5 mm or more, the electrophotographic blade can be stably abutted against the developer carrier. In addition, by fixing the leaf spring material so that the length (l) is 20 mm or less, the vibration of the leaf spring itself can be suppressed.

[0022] When the material of the leaf spring material is a thermoplastic resin, the leaf spring material can be molded by extrusion molding, injection molding, etc. Specifically, when extrusion molding is used, the leaf spring material can be molded by injecting the thermoplastic resin that has been heated and melted into a molding die. When injection molding is used, the leaf spring material can be molded by injecting the thermoplastic resin into a die cavity and cooling it.

[0023] Specific examples of the electrophotographic blade made of a resin layer and a leaf spring material include the form shown in FIG. 2 and the forms shown in FIGS. 3(a) to 3(c). 2 and 3(a) to 3(c), the electrophotographic blade 2 has a support member 44 fixed to a frame 603 of a developing device 601, as shown in FIG. 6, for example. Then, the blade 2 is brought into contact with the surface of the developer carrier 1, which is a contacted member, with the fixed point 40 of the leaf spring material 4 to the support member 44 as a fulcrum. Then, the thickness of the toner layer 605 formed on the surface of the developer carrier 1 is regulated. The toner layer 605 on the developer carrier develops the electrostatic latent image formed on the electrophotographic photosensitive member 5. The resin layer 3 constituting the contact portion that contacts the surface of the contacted member 1 may be provided as a coating that integrally covers the surface of the leaf spring material 4 facing the contacted member 1, the tip surface, and the back surface, as shown in Figures 3(a) and (b). Alternatively, as shown in Figures 2 and 3(c), the resin layer 3 may be provided only on the surface of the leaf spring material 4 facing the contacted member. The shape of the resin layer 3 at the contact point with the contacted member 1 is not particularly limited, and may be a flat shape as shown in Figure 3(a), a curved shape as shown in Figure 2, a convex shape as shown in Figures 3(b) and (c), or a concave shape.

[0024] The resin layer 3 can be formed by a method such as casting, coating, or laminating a sheet. Specifically, when casting is used, a leaf spring material 4 for an electrophotographic blade is placed in a metal mold, and then a mixture of a base agent and a hardener is injected into the metal mold, heated to react and harden, and then demolded to form the resin layer. The mixture of the base agent and the hardener before being heated and hardened is hereinafter referred to as a "resin layer forming mixture." As another example of casting, a method of continuous casting can be used using a molding drum 101 equipped with a molding groove 108 continuous to the outer circumferential cross section and a heating mechanism 109 for heating to a predetermined temperature, and a strip 102 of leaf spring material, as shown in Figures 4 and 5. In the basic manufacturing means of this method, the strip 102 of leaf spring material wound in a coil shape and set in an uncoiler 103 is fed to the molding drum 101 via a pressure contact section (guide roller) 104. While rotating the molding drum 101 about a horizontal axis, a resin layer forming mixture is continuously cast from a casting head 105 into the molding groove 108 on the outer circumferential part of the molding drum, or onto the strip 102 of leaf spring material. The strip 102 of leaf spring material is moved in synchronization with the peripheral speed of the outer peripheral groove of the molding drum along the molding groove 108 so as to seal the groove, and the strip 102 of leaf spring material with the resin layer integrally molded therein is released from the molding groove 108 of the molding drum downstream in the rotation direction of the molding drum. The released strip 102 of leaf spring material passes through guide rollers 104 and conveying rollers 106, and is cut to an appropriate length by a cutting machine 107 provided in a post-process, thereby obtaining an electrophotographic blade according to the present disclosure. In this manufacturing method, the molding groove 108 of the molding drum is covered with the strip 102 of leaf spring material from a position slightly downstream of the injection location of the mixture for forming the resin layer to the removal position, forming a molding cavity 116. The mixture for forming the resin layer is heated and cured while transferring the shape of the molding groove 108 within this covered section. If necessary, measures can be taken to prevent the resin layer forming mixture from leaking from the molding cavity 116. Specifically, tension can be applied to the strip 102 of leaf spring material upstream of the pouring location of the resin layer forming mixture and downstream of the removal position, or a backup belt can be abutted against the outer periphery of the strip 102 of leaf spring material to improve sealing performance. In the case of coating molding, the thermosetting polyurethane precursor solution dispersed in a solvent is applied to the leaf spring material using a coating device such as a sprayer, and then heated and cured to form the contact portion into the leaf spring material. In the case of sheet lamination molding, the thermoplastic resin formed into a sheet shape is laminated to the leaf spring material coated with an adhesive to form the contact portion. When forming the contact portion, an adhesive layer can be formed on the leaf spring material as necessary. Examples of the material for the adhesive layer include hot melt adhesives such as polyurethane, polyester, ethylene vinyl alcohol (EVA), and polyamide.

[0025] [Developing device] An example of a developing device according to another embodiment of the present disclosure is shown in Fig. 6. This developing device 601 is composed of a developer container 6 that stores developer 34, a developer carrier (contacted member, developing roller) 1 that transports the developer 34, and a developer abutting member 8 that regulates the thickness of the developer layer on the surface of the developer carrier. The developer abutting member 8 uses the electrophotographic blade of the present disclosure. The developing device may also be equipped with a developer supply roller 7 and the like, as necessary. In the developing device 601, the developer (toner) 34 is pressed onto the surface of the developer carrier 1 rotating in the direction of the arrow b by the rotation of the developer carrier 1 developer supply roller 7 in the direction of the arrow c. The developer (toner) 34 pressed onto the surface of the developer carrier 1 enters between the developer abutting member 2 and the developer carrier 1 as the developer carrier 1 rotates in the direction of the arrow b, and when passing through this, the toner is rubbed by the surface of the developer carrier 1 and the abutting portion of the developer abutting member 2 and is triboelectrically charged. At this time, the toner on the surface of the developer carrier 1 becomes a toner layer 605 having a predetermined thickness. Then, as the developer carrier 1 rotates in the direction of the arrow b, the toner layer 605 on the surface of the developer carrier 1 is transported to the nip portion with the photoconductor 5 rotating in the direction of the arrow a, and develops the electrostatic latent image (not shown) on the photoconductor 5. Toner remaining on developer carrier 1 that is not consumed in developing the electrostatic latent image is collected from the bottom of developer carrier 1 into developer container 6 as developer carrier 1 rotates, and is stripped off from developer carrier 1 at the nip with developer supply roller 7. At the same time, new toner from the developer container is supplied onto developer carrier 1 by the rotation of developer supply roller 7, and the new toner is used to develop the electrostatic latent image on the photoconductor in the same manner as above. Meanwhile, the toner stripped off from developer carrier 1 is mixed with toner in developer container 603 as developer supply roller 7 rotates.

[0026] [Process Cartridge] A process cartridge according to another embodiment of the present disclosure has a developing device and is configured to be detachably attached to the main body of an electrophotographic image forming apparatus. An example of a process cartridge according to another embodiment of the present disclosure is shown in FIG. 7. The process cartridge shown in FIG. 7 has a developing device 601, a photoconductor 5, a charging roller 11, and a cleaning device 12, which are arranged inside a frame 703 of the process cartridge. The process cartridge is detachably attached to the main body of an electrophotographic image forming apparatus. In addition to the above configuration, the process cartridge according to the present disclosure can also be configured to have a transfer member that transfers a developer image on the photoconductor 5 to a recording material, etc., integrally provided with the above members.

[0027] [Electrophotographic Image Forming Apparatus] An electrophotographic image forming apparatus according to another embodiment of the present disclosure has the developing device. An example of the electrophotographic image forming apparatus according to the present disclosure is shown in FIG. 8. In FIG. 8, image forming units a to d are provided for each color developer, i.e., yellow toner (developer), magenta toner (developer), cyan toner (developer), and black toner (developer). Each image forming unit a to d is provided with a photoconductor 5 as an electrostatic latent image carrier that rotates in the direction of the arrow. Around each photoconductor 5, there are provided a charging device 11 for uniformly charging the photoconductor 5, an exposure means (not shown) for irradiating the uniformly charged photoconductor 5 with laser light 10 to form an electrostatic latent image, and a developing device 9 for supplying developer to the photoconductor 5 on which the electrostatic latent image has been formed, and developing the electrostatic latent image. Meanwhile, a transfer conveyor belt 20 for conveying a recording material 22 such as paper supplied by a paper feed roller 23 is provided suspended around a driving roller 16, a driven roller 21, and a tension roller 19. An electric charge is applied to the transfer / transport belt 20 from an attraction bias power source 25 via an attraction roller 24, so that the recording material 22 is electrostatically attached to the surface thereof and transported. A transfer bias power supply 18 is provided which applies a charge to transfer the developer image on the photoconductor 5 of each of the image forming units a-d onto the recording material 22 transported by the transfer transport belt 20. The transfer bias is applied via a transfer roller 17 arranged on the back side of the transfer transport belt 20. The developer images of each color formed in each of the image forming units a-d are transferred in a superimposed manner in sequence onto the recording material 22 transported by the transfer transport belt 20 which moves in synchronization with each of the image forming units a-d. Furthermore, the color electrophotographic image forming apparatus is provided with a fixing device 15 that fixes the developer image transferred and superimposed onto the recording material 22 by heating or the like, and a conveying device (not shown) that discharges the recording material 22 with the image formed thereon outside the apparatus. On the other hand, each image forming unit is provided with a cleaning device 12 having a cleaning blade that removes residual developer that has not been transferred and remains on each photoconductor 5 and cleans the surface. The cleaned photoconductor 5 is placed in a standby state in which an image can be formed. The developing device 9 provided in each of the image forming units includes a developer container 6 containing developer 34, and a developer carrier 1 that is installed so as to close the opening of the developer container 6 and face the photoconductor 5 with the part exposed from the developer container 6. A developer supply roller 7 is provided in the developer container 6 to supply developer 34 to the developer carrier 1 and to scrape off unused developer remaining on the developer carrier 1 after development. The developer container 6 is also provided with a developer contact member 8 that forms the developer on the developer carrier 1 into a thin film and frictionally charges the developer. These are each disposed in contact with the developer carrier 1, and the developer carrier 1 and the developer supply roller 7 rotate in the forward direction. EXAMPLES

[0028] The electrophotographic blade of the present disclosure will be specifically described below with reference to Production Examples and Examples, but the technical scope of the present disclosure is not limited thereto.

[0029] Example 1 1. Preparation of thermosetting polyurethane composition (Prepolymer synthesis) 57.6 parts by mass of 4,4'-diphenylmethane diisocyanate (MDI) and 42.4 parts by mass of polytetramethylene ether glycol (PTMG) having a molecular weight of 1000 were reacted at 80°C for 3 hours in a nitrogen atmosphere to obtain a prepolymer having an NCO content of 15.8%. The MDI used was trade name "Millionate MT" (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.) The PTMG used was trade name "PTG1000" (trade name, manufactured by Hodogaya Chemical Co., Ltd.)

[0030] (Preparation of raw material mixture for forming thermosetting urethane) The PTMG, 1,4-butanediol (Kishida Chemical Co., Ltd.), trimethylolpropane (Kishida Chemical Co., Ltd.), and a urethane curing catalyst were mixed to obtain a raw material mixture for forming a thermosetting urethane. The curing catalysts used were "Polycat 46" (trade name, manufactured by Evonik Japan) as an isocyanurate catalyst, and "Kao Raiser No. 25" (trade name, manufactured by Kao Corporation) as a urethane catalyst. When the total amount of the raw material mixture after preparation, excluding the catalyst, is taken as 100 parts by mass, the composition of each material is as follows: ·PTMG 96.0 parts by mass 2.6 parts by weight of 1,4-butanediol Trimethylolpropane 1.4 parts by weight Polycat46 130ppm "Kaorizer No. 25" 850ppm

[0031] 2. Manufacturing method of electrophotographic blades An electrophotographic blade was manufactured using the manufacturing apparatus shown in Fig. 10. The prepolymer and curing agent were charged into tanks 110 and 111, respectively, and supplied to a mixing head 114 while being metered by metering pumps 112 and 113. A polyurethane composition was prepared while being uniformly stirred and mixed in the mixing head 114. The molding drum 101 is made of metal, and is supported rotatably and approximately horizontally by a rotating shaft 115. The molding drum 101 of the molding device has a continuous molding groove with a width of 6 mm and a depth of 0.1 mm in the rotation direction, which serves as a prototype of a blade member for an electrophotographic device, and the outer periphery of the molding drum is subjected to a fluorine-containing plating treatment. In this embodiment, the molding drum 101 is rotated at 1 rpm by a driving device. The strip 102 for the leaf spring material was made of stainless steel (SUS304) with a width of 15 mm and a thickness of 0.08 mm, and was placed so as to cover the molding groove on the molding drum 101. The strip 102 was supplied to the molding drum 101 while its running was adjusted by a guide 116 and a guide roller 104. The transport roller 106, which has a drive mechanism separate from the molding drum 101, and the guide roller 104, which adjusts the running of the strip 102, were rotated in accordance with the peripheral speed of the molding drum 101. The polyurethane composition was placed on the molding drum 101 at a position 50 mm upstream from the initial contact point between the molding drum 104 and the strip plate 102 of the leaf spring material in the direction of movement of the molding drum 101. The polyurethane composition was discharged from the above position 5 mm above in the vertical direction. The injected polyurethane composition was heated and cured for a predetermined time in the molding groove of the molding drum 101 by adjusting the temperature to 135°C using a heating mechanism 109 inside the molding drum 101. Thereafter, the polyurethane composition was released from the molding drum 101 and cut to a predetermined size by a cutter 107. Next, the leaf spring material on which the resin layer was formed was welded and fixed to an electrogalvanized steel sheet having a non-chrome surface treatment layer, ZINKOTE 21 (product name: manufactured by Nippon Steel Corporation), as a support member. At this time, the leaf spring material was fixed so that the length L from the fixed end of the leaf spring material to the support member to the other end of the leaf spring material was 12 mm. The force required to displace the other end of the leaf spring material opposite to the fixed end to the support member by 1 mm was 15 N / m. The electrophotographic blade thus obtained was evaluated for vibration absorption and image quality by the following methods.

[0032] 3. Dynamic Viscoelasticity Measurement Measurements were carried out under the following conditions using a dynamic viscoelasticity measuring device (product name: Iplexer 500N, manufactured by GABO). The resin layer for measurement was prepared by cutting the resin layer out from a leaf spring material. The evaluation results at temperatures of 5°C, 25°C, and 40°C are shown in Tables 5 to 7. Static load: 1.5% Dynamic Load: 0.25% Measurement temperature range: -30℃~50℃ Frequency: 10Hz Sampling: Every 2°C Heating rate: 0.5℃ / min

[0033] 4. Measurement of number average molecular weight of hydrolyzate of polyurethane composition The resin layer cut from the leaf spring material was placed in an aqueous sodium hydroxide solution and subjected to thermal hydrolysis at a temperature of 80°C to obtain a hydrolyzate. Next, the solution was neutralized with 1N hydrochloric acid and then dried to obtain a solid hydrolyzate. Next, the solid was dissolved in THF to prepare a 0.1% by mass THF solution. Using this THF solution, the molecular weight distribution of the hydrolyzate was measured under the following conditions. Measuring equipment: HLC-8120GPC (Tosoh Corporation) Column: TSKgel SuperHZMM (Tosoh Corporation) x 2 Solvent: THF (20mmol / L triethylamine added) Temperature: 40℃ THF flow rate: 0.6 ml / min Detector: RI (refractive index) detector.

[0034] A calibration curve was created using TSK standard polystyrenes A-1000, A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40, F-80, and F-128 (manufactured by Tosoh Corporation) as standard samples for creating a calibration curve. Based on this, the proportion of polyether polyol in the hydrolysate and its number average molecular weight, as well as the amount of alcohol with a molecular weight of 200 or less per gram of the hydrolysate, were determined from the retention times of the measurement samples obtained.

[0035] 5. Measurement of vibration damping properties of electrophotographic image forming blades The vibration damping measurement of the developer regulating blade was carried out using the device shown in FIG. 9. That is, the electrophotographic blade 2 was brought into contact with the metal roller 51 via the spacer 50 at a linear pressure of 40 gf / cm. The spacer 50 was present over the entire longitudinal area of ​​the metal roller 51 and the electrophotographic blade 2, and had a thickness of 1 mm. The non-contact side end of the electrophotographic blade 2 was fixed at a position where the above-mentioned contact pressure was applied to the metal roller 51. In addition, the displacement of the back side of the contact part of the electrophotographic blade 2 was obtained using a micro vibration meter 52 (laser Doppler vibrometer LV-1800: manufactured by Ono Sokki). In this state, the spacer 50 was pulled out from the contact part in the tangential direction of the metal roller 51, and the electrophotographic blade 2 was made to collide with the metal roller 51. After the collision, the electrophotographic blade 2 bounced off the metal roller 51 and collided again, repeating the vibration, and the time T (milliseconds (msec)) until the amplitude became 10 μm or less (hereinafter also referred to as the "vibration absorption time") was measured. This evaluation was carried out under environmental conditions of temperatures of 5°C, 25°C, and 40°C.

[0036] 6. Image Assessment First, a color laser printer (product name: SateraLBP5400, manufactured by Canon Inc.) was prepared as an electrophotographic image forming apparatus. However, the output speed of the recording medium was modified to 200 mm / sec (A4 portrait output). The image resolution was 600 dpi, and the output of the primary charge was a DC voltage of -1100 V. In addition, an electrophotographic process cartridge for the color laser printer was prepared as an electrophotographic process cartridge. The developer amount control blade attached to this electrophotographic process cartridge was replaced with the electrophotographic blade according to this embodiment. At this time, the displacement of the other end of the leaf spring opposite to the fixed end 41 relative to the support member was adjusted to 1 mm. The electrophotographic process cartridge was loaded into the color laser printer, and an electrophotographic image was formed. As the image, an image (hereinafter also referred to as an "E letter image") was formed in which the alphabetic letter "E" of 4 points was printed with a coverage rate of 1% of the area of ​​A4 size paper. The image was formed by so-called intermittent printing, in which two E letter images were continuously printed and then stopped for 3 seconds. Then, after printing 20,000 E letter images, one halftone image (an image in which horizontal lines with a width of 1 dot and an interval of 2 dots are drawn in the direction perpendicular to the rotation direction of the electrophotographic photoreceptor) was printed. The obtained halftone image was visually observed, and the presence and degree of banding caused by vibration of the developing roller and uneven density or streaks caused by poor regulation of the toner layer by the electrophotographic blade were judged according to the criteria described below. This evaluation was performed under environments of temperatures of 5°C, 25°C, and 40°C.

[0037] Evaluation criteria: <Banding> Rank A: No banding observed. Rank B: Banding can be seen in some parts of the halftone image at the pitch of the developing roller. Rank C: Banding is observed throughout the halftone image. <Uneven density, streaks> Rank A: No uneven density or streaks are observed. Rank B: Uneven density and streaks are observed.

[0038] [Examples 2 to 19] An electrophotographic blade was obtained in the same manner as in Example 1, except that at least one of the thickness of the leaf spring, the urethane raw material for forming the resin layer, and the thickness of the resin layer was changed as shown in Tables 1 to 3.

[0039] [Comparative Examples 1 to 6] An electrophotographic blade was obtained in the same manner as in Example 1, except that at least one of the thickness of the leaf spring, the urethane raw material for forming the resin layer, and the thickness of the resin layer was changed as shown in Table 4. The evaluation results of the electrophotographic blades according to Examples 1 to 19 and Comparative Examples 1 to 6 are shown in Tables 5 to 7. As shown in Tables 5 and 6, the electrophotographic blades according to Examples 1 to 19 had a vibration absorption time T of 3.0 msec or less at all measurement temperatures, and no banding, uneven density, or streaks were observed. The electrophotographic blade according to Comparative Example 1 had an elastic modulus of 0.8 MPa at a temperature of 40° C. In addition, uneven density and streaks were observed in the output image in the same temperature environment. This is believed to be because the resin layer was too soft at that temperature, resulting in a weak deformation recovery force and an uneven thickness of the toner layer. The electrophotographic blade according to Comparative Example 2 had an elastic modulus of 63.2 MPa at a temperature of 5° C. The vibration absorption time T at the same temperature was 3.1 msec, and banding was observed in a halftone image output in the same temperature environment. This is believed to be because the vibration was not sufficiently alleviated at a temperature of 5° C., resulting in periodic thin portions in the thickness of the toner layer, causing the banding. The electrophotographic blade according to Comparative Example 3 had a tan δ of 0.03 at a temperature of 40° C. The vibration absorption time T at the same temperature was 3.2 msec, and banding was observed in a halftone image output in the same temperature environment. This is believed to be because vibration was not sufficiently alleviated at a temperature of 40° C., resulting in periodic thin portions in the thickness of the toner layer, causing banding. The electrophotographic blade according to Comparative Example 4 had a tan δ of 0.71 at a temperature of 5° C. In addition, halftone images output in the same temperature environment had uneven density and streaks. This is believed to be because the resin layer took a long time to recover from deformation at the same temperature, resulting in an uneven thickness of the toner layer. The electrophotographic blade according to Comparative Example 5 had excellent vibration absorption ability, but density unevenness and streaks were observed in halftone images output under all temperature environments, as shown in Table 7. This is believed to be because the resin layer had a thickness of 2.10 mm, so the force applied to the toner layer on the surface of the developing roller varied depending on the location, causing variation in the thickness of the toner layer. As shown in Table 7, the electrophotographic blade according to Comparative Example 6 had a seismic intensity absorption time T exceeding 3.0 msec at temperatures of 25°C and 40°C, and banding was observed in halftone images output in the same temperature environment. This is believed to be because the resin layer was thin at 0.04 mm, and was unable to sufficiently mitigate the vibration caused by the developing roller, resulting in periodic thin areas in the thickness of the toner layer. In Comparative Examples 1, 4, and 5, it became impossible to form a uniform thin layer of developer, and poor regulation occurred.

[0040] [Table 1]

[0041] [Table 2]

[0042] [Table 3]

[0043] [Table 4]

[0044] [Table 5]

[0045] [Table 6]

[0046] [Table 7] [Explanation of symbols]

[0047] 1 Contact member (developer carrier) 2, 8 Electrophotographic image forming blade 3 Resin layer 4 Leaf spring material 41: Fixed end 42: Other end (free end)

Claims

1. An electrophotographic blade, comprising: The electrophotographic blade is a developer amount regulating blade that is brought into contact with a developer carrying member, The electrophotographic blade comprises: A leaf spring material; a resin layer that covers at least a portion of the surface of the leaf spring material and forms a contact portion with a developer carrier; having When the leaf spring material is fixed at one end thereof such that the length (L) from the fixed end to the other end is 5 mm to 20 mm, a force required to displace the other end by 1 mm is 5 N / m or more and 100 N / m or less, The resin layer satisfies the following requirements (1) to (3): An electrophotographic blade characterized by: Requirement (1) The thickness of the resin layer is 0.05 mm or more and 2.00 mm or less. Requirement (2) The value of tan δ of the resin layer at 5° C. or more and 40° C. or less, measured under a frequency condition of 10 Hz, is 0.05 or more and 0.70 or less. Requirement (3) The storage modulus of the resin layer is 1.0 MPa or more and 60.0 MPa or less.

2. 2. The electrophotographic blade according to claim 1, wherein said resin layer is a thermosetting urethane elastomer.

3. 3. The electrophotographic blade according to claim 2, wherein the thermosetting urethane elastomer has a structure represented by the following formula (1) between two adjacent urethane bonds: Formula (1) -[(CH ２ ) ｎ O] ｍ - (n represents an integer of 2 or more, and m represents an integer of 1 or more, provided that n+m is a number necessary for making the average molecular weight of the alkylene oxide structure portion in formula (1) 380 or more and 1600 or less).

4. The hydrolyzate of the thermosetting urethane elastomer contains a component represented by the following formula (2): The ratio of the component to the hydrolysate is 50 wt % or more and 80 wt % or less. The electrophotographic blade according to claim 2 : Formula (2) H. ２ ) ｎ O] ｍ -H (n represents an integer of 2 or more, and m represents an integer of 1 or more, provided that n+m is a number necessary for making the average molecular weight of the alkylene oxide structure portion in formula (2) 380 or more and 1600 or less).

5. 5. The electrophotographic blade according to claim 4, wherein the hydrolysate does not contain alcohol having a molecular weight of 200 or less.

6. 5. The electrophotographic blade according to claim 4, wherein the content of alcohol having a molecular weight of 200 or less in said hydrolysate is 0.25 mmol / g or less.

7. A developer carrier; a developer amount regulating blade in contact with the developer carrying member; An electrophotographic image forming apparatus comprising:

7. An electrophotographic image forming apparatus, wherein the developer amount regulating blade is the electrophotographic blade according to claim 1.

8. A developer carrier; a developer amount regulating blade in contact with the developer carrying member; A process cartridge detachably mountable to a main body of an electrophotographic image forming apparatus, comprising:

7. A process cartridge, wherein the developer amount regulating blade is the electrophotographic blade according to claim 1.

Images