JP4298037B2 - Developer amount regulating member and developing device - Google Patents

Description

表１に示されるように、実施例１〜４では、空回転が８時間までトナーの漏れが起こらなかったのに対し、比較例２、３では、現像ブレード４と現像スリーブ３間の端部の隙間が原因と思われるトナー漏れが、試験の初期から発生した。また比較例１では、空回転１時間で現像ブレード端部へのトナー融着が原因と思われるトナー漏れが発生した。
【００５４】
本実施の形態においては、長手方向長さ３００mmの現像ブレード４を用いたが、上記の反り量は２００〜３５０mmの範囲でも適用できる。
【００５５】
以上説明したように、現像剤担持体（現像スリーブ）３に向けて付勢される弾性部材（摩擦帯電部材）４ｂと、前記弾性部材４ｂを支持している支持部材４ａとを有し、現像剤担持体３上の現像剤の量を規制する現像剤量規制部材（現像ブレード）４において、前記支持部材４ａの短手方向端部を支持した際に、前記弾性部材４ｂの長手方向端部が前記支持部材側に反る。
【００５６】
前記反り量は、１０μｍ以上４５０μｍである。
【００５７】
好ましくは、前記支持部材４ａの厚さは、０．０５mm以上０．５mm以下である。
【００５８】
好ましくは、前記弾性部材４ｂの厚さは、０．５mm以上３mm以下である。
【００５９】
【発明の効果】
以上説明したように、本発明によると、現像剤量規制部材の両端部で現像剤担持体との間に軽圧当接を実現して、トナーの融着を防ぐことができ、トナーの融着によるトナー漏れを防止することができる。
【図面の簡単な説明】
【図１】本発明の現像装置１４一実施の形態を示す縦断面図である。
【図２】現像ブレードの反り量の測定方法を示す説明図である。
【図３】現像装置１４を採用するのに適した電子写真装置の一例の縦断面図である。
【図４】現像装置における現像スリーブ上トナーの現像ブレードによる規制を示す説明図である。
【符号の説明】
１ 像担持体（感光ドラム）
２ 現像容器
３ 現像剤担持体（現像スリーブ）
４ 現像剤量規制部材（現像ブレード）
４ａ 支持部材
４ｂ 弾性部材（摩擦帯電部材）
５ 弾性ローラ
６ トナー
１４ 現像装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a developing device used for visualizing an electrostatic latent image formed on an image carrier of an image forming apparatus, and a developer amount regulating member for regulating the amount of developer on the developer carrier. It is.
[0002]
[Prior art]
In an electrophotographic image forming apparatus, the latent image is visualized (developed) by developing the electrostatic latent image formed on the image carrier with a developer using a developer.
[0003]
In this developing device, as shown in FIG. 4, a developing unit that carries toner (developer) (not shown) on the surface of a developing sleeve 103 that rotates in the direction of an arrow as a developer carrying member and that faces the image carrying member. In the course of the conveyance, toner is allowed to pass between the developing sleeve 103 and the rubber or metal developer amount regulating blade (developing blade) 104 abutted on the surface of the developing sleeve 103 and regulated. A thin layer of toner is formed on the developing sleeve 103, and triboelectric charge (tribo) suitable for developing the latent image is applied to the toner.
[0004]
As the rubber development blade 104, there is one using a single rubber sheet such as urethane rubber, but as shown in the figure, the rubber sheet 104b is supported by a metal support member 104a as a friction charging member. It is used a lot.
[0005]
[Problems to be solved by the invention]
In recent years, in order to cope with various toners including a new type of toner, it has become an important issue for developing blades to improve performance such as tribocharging and toner fusion prevention.
[0006]
Recent toners include low-melting-point toners (sharp melt toners) that can be fixed at lower temperatures than conventional ones, or non-magnetic toners (non-mag toners) and polymerized toners that are associated with colorization. Has appeared.
[0007]
For these toners, particularly high-performance triboelectric charging is required. For example, if the contact pressure of the developing blade 104 to the developing sleeve 103 is increased, the necessary triboelectric chargeability can be ensured.
[0008]
However, when the contact pressure is increased, the toner easily adheres to the surface of the developing blade 104, and particularly, the toner pool is formed at the end portion of the developing blade 104, so that toner fusion occurs remarkably. When toner fusing occurs on the surface of the developing blade, the triboelectric chargeability of the developing blade 104 is reduced, and insufficiently charged toner is generated. The toner leaks from the developing device, and not only in the developing device but also in the entire image forming apparatus. Contamination problems can occur.
[0009]
Therefore, for a surface layer material that can satisfy the triboelectric chargeability even when the contact pressure is light, for example, a negative toner, a nylon resin that is easily positively charged can be used for the triboelectric charging member 104b. However, if the developing blade 104 having a high flatness of the surface layer material is used, a difference occurs in the contact pressure between the central portion and the end portion along the longitudinal direction of the developing sleeve 103 of the developing blade 104, so that a good friction is obtained. The range of the developing blade 104 that can realize the contact pressure that can acquire the charging property is reduced. For this reason, it is necessary to assemble the developing blade 104 and the like with high accuracy, and there is a problem in that the cost of the developing device, and hence the image forming apparatus, is increased.
[0010]
An object of the present invention is to provide a developer amount regulating member capable of preventing toner fusion at an end portion, and a developing device including the same.
[0011]
[Means for Solving the Problems]
The main aspect of the present invention is a flat plate-like support member attached to the developer container so as to have a spring property and located along the longitudinal direction of the developer carrier, and the amount of developer on the developer carrier. An elastic member for regulating the developer, and the elastic member is injected and filled with an elastomer in the mold in a state where the support member is inserted into the mold, whereby the developer carrier longitudinally over by the developer carrying member and the abutment surface for abutment, on one side of the support member in the longitudinal direction of the contact surface and is a surface on the opposite side front Symbol support member and the support surface for being supported, with is shaped to have a, by mechanically compressed before cooling and solidifying the injection-filled elastomer into the mold, the support member is the developer container The length of the elastic member when attached to Wherein the opposite ends of the direction is shaped such that the warps from the contact surface side to the supported side.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic configuration diagram showing an embodiment of a developing device of the present invention.
[0013]
The developing device 14 shown in FIG. 1 includes a developing sleeve 3 as a developer carrier at an opening facing the photosensitive drum 1 as an image carrier of a developing container 2 containing toner (developer) 6. The developing sleeve 3 protrudes into the developing container 2 with a substantially right half-periphery surface as viewed in the figure, and a substantially half left-hand circumferential surface is exposed to the outside of the developing container 2 so as to face the photosensitive drum 1. It is installed horizontally so that it can rotate freely. A slight minute gap is provided between the developing sleeve 3 and the photosensitive drum 1. The developing sleeve 3 is driven to rotate in the arrow b direction with respect to the rotation of the photosensitive drum 1 in the arrow a direction.
[0014]
In the developing container 2, a developing blade 4 is installed above the developing sleeve 3, and an elastic roller 5 is provided at a position upstream of the developing blade 4 in the rotation direction of the developing sleeve 3.
[0015]
The developing blade 4 includes a support member 4a and a friction charging member (elastic member) 4b provided near the tip in the direction perpendicular to the longitudinal direction (the same direction as the longitudinal direction of the developing sleeve 3) (width direction). Have. The thickness of the support member 4a is preferably 0.05 mm or more and 0.5 mm or less. The thickness of the friction charging member 4b is preferably 0.5 mm or more and 3 mm or less. The developing blade 4 is attached to the developing container 2 via the support member 4 a so as to be inclined so as to be lowered toward the upstream side in the rotation direction of the developing sleeve 3, and the friction charging member 4 b is disposed on the upper outer periphery of the developing sleeve 3. The surface is elastically biased to abut against the surface in the rotational direction.
[0016]
According to the present embodiment, the developing blade 4 is formed in a shape in which both end portions in the longitudinal direction have a height difference in flatness of the contact surface within 30 mm from each end surface. This will be described later.
[0017]
The elastic roller 5 is a toner stripping / supplying member for the developing sleeve 3, is in contact with a portion of the developing sleeve 3 opposite to the photosensitive drum 1, and is rotatably supported.
[0018]
In the developing device 14, the elastic roller 5 rotates in the direction of the arrow c, and the toner 6 is carried and supplied to the vicinity of the developing sleeve 3 by the rotation of the elastic roller 5. The toner 6 on the elastic roller 5 is rubbed against the developing sleeve 3 and is carried on the developing sleeve 3 at the contact portion (nip portion).
[0019]
The toner 6 carried on the developing sleeve 3 is conveyed to a contact portion with the developing blade 4 as the developing sleeve 3 rotates in the direction of arrow b, and enters between the developing blade 4 and the developing sleeve 3, where When it passes through, it is rubbed by the surfaces of both the developing sleeve 3 and the developing blade 4 and sufficiently charged by friction. Then, it passes between the developing blade 4 and the developing sleeve 3 and is formed on the developing sleeve 3 as a thin layer of toner 6.
[0020]
The toner 6 formed in a thin layer on the developing sleeve 3 is conveyed to a developing unit where the developing sleeve 3 and the photosensitive drum 1 are opposed to each other with a minute gap. In the developing unit, an alternating voltage in which an alternating current is superimposed on a direct current, for example, is applied as a developing bias between the developing sleeve 3 and the photosensitive drum 1, so that the toner 6 on the developing sleeve 3 becomes an electrostatic latent image on the photosensitive drum 1. The latent image is visualized as a toner image.
[0021]
The toner 6 remaining on the developing sleeve 3 without being consumed for development in the developing unit is collected into the developing container 2 from the lower portion of the developing sleeve 3 as the developing sleeve 3 rotates. The collected toner 6 is peeled off from the developing sleeve 3 by the elastic roller 5 at the contact portion with the developing sleeve 3. At the same time, new toner 6 is supplied onto the developing sleeve 3 by the rotation of the elastic roller 5, and the new toner 6 is conveyed again to the contact portion between the developing sleeve 3 and the developing blade 4.
[0022]
Most of the toner 6 thus peeled off is conveyed and mixed into the toner 6 in the developing container 2 as the elastic roller 5 rotates, and the charged charge of the peeled toner is dispersed.
[0023]
As the toner 6, a magnetic toner, a nonmagnetic color, or the like is used, and an average particle diameter of about 3 to 15 μm is preferable.
[0024]
In the present embodiment, the longitudinal end portion of the frictional charging member 4b warps toward the support member 4a when the short end portion of the support member 4a is supported. The developing blade 4 having such a shape can be obtained by forming the friction charging member 4b using a specific material and a molding method.
[0025]
According to the present embodiment, the developing blade 4 having a difference in flatness at both end portions has a predetermined amount of warping as follows.
[0026]
As shown in FIG. 2, the amount of warpage of the developing blade 4 when the supporting member 4a of the developing blade 4 is sandwiched between a pair of fixed metal plates 9a and 9b and attached to the developing container 2 of the developing device 14 of FIG. There can be a difference in flatness of the contact surface with the developing sleeve 3. The amount of warpage is defined as the difference between the highest value and the lowest value of the contact surface within 30 mm from each end face of both ends of the attached developing blade 4. In the present embodiment, the developing blade 4 takes the minimum value of the abutting surface at each end face at both ends, and the warping amount is in the range of 10 μm to 450 μm. The state shown in FIG. 2 is the same as the state in which the short-side end of the support member 4a is supported before the developing sleeve 3 is provided in the developing device 14.
[0027]
If the amount of warpage of the developing blade 4 is 10 μm or more and 450 μm or less, preferable light pressure contact with the developing sleeve 3 can be realized at both ends. If the amount of warpage is less than 10 μm, the effect of reducing the contact pressure may not be obtained. On the other hand, if it exceeds 450 μm, a gap is generated at the contact portion with the developing sleeve 3, and the toner is not sufficiently charged by friction and may cause toner leakage.
[0028]
The developing blade 4 having the above configuration is formed by injection compression molding an elastomer (rubber) of a thermoplastic resin into a mold in which a support member 4a made of a spring sheet metal is inserted, thereby forming a friction charging member 4b having elasticity. Thus, the shape warped toward the support member 4a, that is, the planar shape on the rubber side can be formed into a convex shape having a curvature. When the developing blade 4 is attached to the developing device 14, the flatness of the contact surface with the developing sleeve 3 has a difference in level, and can be formed in a shape having a minimum value at each end face of both ends.
[0029]
For example, if an elastomer is injected and filled into a mold having a cavity about 1.5 times the desired thickness of the rubber and the elastomer is mechanically compressed to the desired thickness before the elastomer cools and solidifies, the elastomer Becomes overfilled, and stress remains in the elastomer, resulting in a shape that warps to the support member side. That is, by changing the filling amount of the elastomer and the compressive force, it is possible to obtain a molded product of the developing blade 4 having an arbitrary amount of warpage.
[0030]
If the obtained molded product is annealed at an appropriate temperature, it tends to return to a flat surface due to relaxation of residual stress. Therefore, particularly when a crystalline thermoplastic elastomer is used, shrinkage occurs due to crystallization, so that the developing blade 4 can be formed into a shape having an arbitrary curvature.
[0031]
Here, as the thermoplastic elastomer, for example, polyether block amide which is a block copolymer of polyamide and polyether can be used. Examples of the polyamide component include polyamides 6, 6 · 6, 6 · 10, 6 · 12, 11, 12, 12 · 12, and polyamides obtained by polycondensation between different types of monomers of these polyamides, preferably, A polyamide having a terminal amino group carboxylated with a dibasic acid or the like is used.
[0032]
Dibasic acids include: aliphatic saturated dicarboxylic acids such as nitric acid, succinic acid, adipic acid, suberic acid, sebacic acid and dodecanedioic acid; aliphatic unsaturated dicarboxylic acids such as maleic acid; aromatics such as phthalic acid and terephthalic acid And polydicarboxylic acids synthesized from diols such as ethylene glycol, butanediol, hexanediol, octanediol, and decanediol.
[0033]
Polyether components include homopolymerized or copolymerized polyether diols such as polyethylene glycol, polypropylene glycol, and polytetotamethylene glycol, and polyether diamines that are aminated at both ends. Polyamide forms a block copolymer of polyether and polyamide having an ester bond (polyetherpolyesteramide) or amide engagement (polyetherpolyamide).
[0034]
Since the developing device 14 of the present embodiment uses the developing blade 4 having the above-described configuration, light pressure contact can be realized at both ends of the developing sleeve 3, toner fusion at the end can be prevented, and toner fusion can be achieved. The resulting toner leakage can be prevented.
[0035]
An example of an electrophotographic apparatus suitable for adopting the developing device 14 of the present embodiment is shown in FIG.
[0036]
In FIG. 3, a photosensitive drum 1 is a drum-type electrophotographic photosensitive member having a conductive support such as aluminum and a photosensitive layer formed on the outer peripheral surface thereof as basic constituent layers. The photosensitive drum 1 is rotationally driven around the support shaft at a predetermined peripheral speed in the clockwise direction in FIG.
[0037]
The surface of the photosensitive drum 1 is uniformly charged to a predetermined polarity and potential by the corona discharger 12, and the charged photosensitive drum 1 is then exposed to the desired image information by the exposure means L (laser beam scanning). The electrostatic latent image 13 corresponding to the image information is formed on the surface upon exposure and slit exposure of the original image. The electrostatic latent image 13 is developed as a toner image by the developing device 14.
[0038]
The transfer material P is conveyed from a supply unit (not shown) to the photosensitive drum 1 and conveyed to a transfer unit between the photosensitive drum 1 and the transfer unit 15 with an appropriate timing synchronized with the rotation of the photosensitive drum 1. . The toner image formed on the photosensitive drum 1 is transferred to the surface of the transfer material P by the action of the transfer means 15.
[0039]
The transfer material P that has received the transfer of the toner image is separated from the photosensitive drum 1 and sent to the heat fixing roller 18 where the toner image is fixed to the transfer material P and output as a print image. After the toner image is transferred, the photosensitive drum 1 is cleaned by removing contaminants such as transfer residual toner from the surface by the cleaning means 16 and then used again for image formation.
[0040]
A plurality of process elements of the electrophotographic apparatus such as the photosensitive drum 1, the charger 12, the developing device 14, and the cleaning means 16 can be integrated into a process cartridge. The process cartridge is detachably installed in the apparatus main body using guide means such as a rail provided in the image forming apparatus main body.
[0041]
Examples of the electrophotographic apparatus that can use the developing device 14 of the present embodiment include electrophotographic application apparatuses such as a copying machine, a laser beam printer, an LED printer, and an electrophotographic plate making system.
[0042]
In the above description, the case of an electrophotographic apparatus in the case of a single color has been described. However, in a color LBP that forms a color image using toner of four colors, a developing device similar to the developing device 14 is installed for four colors. Each time a latent image of each color is developed on the photosensitive drum 1 and a toner image of each color is obtained, the toner image is temporarily transferred to an intermediate transfer member such as a roller or a belt, and then transferred onto the intermediate transfer member 4. A color image is obtained by collectively transferring and fixing a color toner image onto a transfer material.
[0043]
Hereinafter, a specific example of the present embodiment will be described.
[0044]
[Example 1]
A phosphor bronze plate having a thickness of about 0.1 mm as a support member 4a was mounted in the mold, and a polyamide elastomer of thermoplastic elastomer (Daiamide PAE E40-S3 manufactured by Daicel Huls) was dried at 70 ° C. for 6 hours. This was injection compression molded into a mold having a mold temperature of 40 ° C. at a melting temperature of 250 ° C. to obtain a molded product in which a polyamide elastomer friction charging member 4b having a thickness of about 1 mm was formed on the support member 4a. The molded product was annealed in an electric furnace at 70 ° C. for 60 minutes, and then cut into a predetermined size to obtain the developing blade 4.
[0045]
[Example 2]
A developing blade 4 was obtained in the same manner as in Example 1 except that the annealing temperature was 60 ° C.
[0046]
[Example 3]
A developing blade 4 was obtained in the same manner as in the first embodiment except that the annealing temperature was 50 ° C.
[0047]
[Example 4]
A developing blade 4 was obtained in the same manner as in Embodiment 1 except that the annealing temperature was 40 ° C.
[0048]
[Comparative Example 1]
A developing blade 4 was obtained in the same manner as in Embodiment 1 except that the annealing temperature was 80 ° C.
[0049]
[Comparative Example 2]
A developing blade 4 was obtained in the same manner as in Embodiment 1 except that the annealing temperature was 40 ° C. and the time was 30 minutes.
[0050]
[Comparative Example 3]
The molded product obtained in the first embodiment was not annealed but was cut as it was to obtain the developing blade 4.
[0051]
The development blade 4 and the development sleeve 3 of Examples 1 to 4 and Comparative Examples 1 to 3 are developed as shown in FIG. 1 so that the contact pressure between the development blade 4 and the development sleeve 3 is 18 gf / cm, respectively. The device 14 was attached. As the developing sleeve 3, a 10-point average roughness Rz = 2.5 μm was used by blasting an aluminum tube. The developing container 2 was equipped with a foamed urethane sponge roller as the elastic roller 5. This sponge roller is suitable for sufficiently applying the toner to the developing sleeve 3 and peeling off the remaining toner without being developed and returning it to the developing container 2 again.
[0052]
The developing device 14 was installed in an idle rotating machine of a laser beam printer (Lasershot manufactured by Canon), and an 8 hour idling durability test was performed using non-magnetic black toner in a room temperature environment. The toner leakage due to the fusion of the toner to the developing blade 4 at that time was visually observed. The results are shown in Table 1. In Table 1, the symbol ◯ indicates that there is no phenomenon for each observation item, and × indicates that there is a phenomenon.
[0053]
[Table 1]

As shown in Table 1, in Examples 1 to 4, toner leakage did not occur until 8 hours, whereas in Comparative Examples 2 and 3, the end between the developing blade 4 and the developing sleeve 3 was used. The toner leakage that seems to be caused by this gap occurred from the beginning of the test. Further, in Comparative Example 1, the toner leakage that seems to be caused by the toner fusion to the end of the developing blade occurred in 1 hour of idling.
[0054]
In the present embodiment, the developing blade 4 having a length of 300 mm in the longitudinal direction is used. However, the above warpage amount can be applied in the range of 200 to 350 mm.
[0055]
As described above, the elastic member (friction charging member) 4b biased toward the developer carrying member (developing sleeve) 3 and the support member 4a supporting the elastic member 4b are provided. In the developer amount regulating member (developing blade) 4 that regulates the amount of developer on the agent carrier 3, the longitudinal end portion of the elastic member 4 b is supported when the short end portion of the support member 4 a is supported. Warps toward the support member.
[0056]
The amount of warpage is 10 μm or more and 450 μm.
[0057]
Preferably, the thickness of the support member 4a is 0.05 mm or more and 0.5 mm or less.
[0058]
Preferably, the thickness of the elastic member 4b is not less than 0.5 mm and not more than 3 mm.
[0059]
【The invention's effect】
As described above, according to the present invention, light pressure contact can be realized between the developer carrying member at both ends of the developer amount regulating member, and toner fusion can be prevented. It is possible to prevent toner leakage due to wearing.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a developing device 14 of the present invention.
FIG. 2 is an explanatory diagram showing a method for measuring the amount of warping of the developing blade.
FIG. 3 is a longitudinal sectional view of an example of an electrophotographic apparatus suitable for employing the developing device 14;
FIG. 4 is an explanatory diagram illustrating a restriction by a developing blade of toner on a developing sleeve in a developing device.
[Explanation of symbols]
1 Image carrier (photosensitive drum)
2 Developing container 3 Developer carrier (developing sleeve)
4 Developer amount regulating member (developing blade)
4a Support member 4b Elastic member (friction charging member)
5 Elastic roller 6 Toner 14 Developing device

Claims (5)

In a developer amount regulating member used in a developing device having a developing container and a developer carrying member that carries and carries the developer,
A flat plate-shaped support member that has springiness and is attached to the developer container in the longitudinal direction of the developer carrier;
An elastic member for regulating the amount of developer on the developer carrier ,
The elastic member is abutted against the developer carrier along the longitudinal direction of the developer carrier when the elastomer is injected and filled in the die with the support member inserted into the die. to have a contact surface for contact, and a supported surface for being supported on one side of the support member in the longitudinal direction of the front Symbol support a surface opposite to the abutment surface The elastomer injected into the mold is mechanically compressed before being cooled and solidified, so that when the support member is attached to the developing container, developer amount regulating member, characterized in that both end portions are shaped such that the warps from the contact surface side to the supported side.   One end side in the short direction of the support member supports the supported surface across the longitudinal direction of the support member, and the other end side in the short direction of the support member extends across the longitudinal direction of the support member. The warping of the central portion in the longitudinal direction of the elastic member is smaller than the warping of both ends in the longitudinal direction of the elastic member by being attached to the developing container while being sandwiched between a pair of fixing plates. The developer amount regulating member according to claim 1, wherein   3. The developer amount regulating member according to claim 1, wherein the elastic member is one that is annealed after the elastomer is mechanically compressed and cooled and solidified. 4. In a developing device used in an image forming apparatus,
A developer container;
A developer carrier for carrying and conveying the developer;
A flat plate-shaped support member that has springiness and is attached to the developer container in a longitudinal direction of the developer carrier;
An elastic member for regulating the amount of developer on the developer carrier ,
The elastic member is abutted against the developer carrier along the longitudinal direction of the developer carrier when the elastomer is injected and filled in the die with the support member inserted into the die. to have a contact surface for contact, and a supported surface for being supported on one side of the support member in the longitudinal direction of the front Symbol support a surface opposite to the abutment surface The elastomer injected into the mold is mechanically compressed before being cooled and solidified, so that when the support member is attached to the developing container, developing apparatus is characterized in that both end portions are shaped such that the warps from the contact surface side to the supported side.   One end side in the short direction of the support member supports the supported surface across the longitudinal direction of the support member, and the other end side in the short direction of the support member extends across the longitudinal direction of the support member. The warping of the central portion in the longitudinal direction of the elastic member is smaller than the warping of both ends in the longitudinal direction of the elastic member by being attached to the developing container while being sandwiched between a pair of fixing plates. The developing device according to claim 4, wherein:

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