JP4530355B2 - Developer amount regulating blade - Google Patents

Description

  The present invention relates to a developer amount regulating blade (hereinafter also simply referred to as “blade”), and in particular, develops an electrostatic latent image formed on an image carrier in various image forming apparatuses such as a copying machine, a printer, and a facsimile machine. And a developer amount regulating blade for regulating the amount of developer used for visualization.

  In electrophotographic or electrostatic recording type image forming apparatuses such as copiers, facsimiles, printers, etc., particularly for color, a non-magnetic developer is charged, and the developer is transferred to the photosensitive drum by the charge. In this method, the developer is carried on the outer periphery of the developing roller, and the amount of the developer is regulated by a blade attached in a state facing the outer peripheral surface of the developing roller. This is done by frictionally charging the developer.

  FIG. 4 is a cross-sectional view showing a state in which the blade is attached to the image forming apparatus. The blade 101 includes a thin strip-shaped leaf spring portion 102 and a rubber portion 103 extending in the length direction of the leaf spring portion. It consists of an elastic member 104 and a support member 105. The leaf spring portion 102 is usually made of metal, for example, stainless steel, and the rubber portion 103 is attached only to one surface in the thickness direction of the leaf spring portion 102 (see Patent Document 1).

  The blade 101 is attached in a state where the one surface of the leaf spring portion 102 provided with the rubber portion 103 is opposed to the peripheral surface of the developing roller 106, and is carried on the peripheral surface by the rotation of the developing roller 106. The amount of developer acts to be regulated by the rubber part 103.

  When the elastic member 103 constituting the blade 101 is manufactured, if the rubber part 103 is a thermosetting material such as silicone rubber, the high-temperature mold cavity in which the leaf spring part 102 is loaded is provided. A rubber material is injected and thermally cured in the cavity, and then cooled integrally with the leaf spring portion to form the elastic member 104. If the rubber portion 103 is thermoplastic, the rubber material heated and fluidized is injected into a mold cavity similarly loaded with the leaf spring portion, and then integrated with the leaf spring portion 102. The elastic member 104 is formed by cooling and solidifying.

  In the elastic member 104 formed in this manner, the rubber portion 103 is integrated with the leaf spring portion 102 in a thermally expanded state, so that the rubber portion 103 of the thin leaf spring portion 102 is thermally contracted during the cooling process. Shrinks one surface where the rubber is pasted, but the other surface where the rubber part is not pasted does not act on the other surface. As shown in FIGS. 5A and 5B, the elastic member 104 of FIG. 5 is warped with the one surface facing inward, and the both sides in the longitudinal direction are lifted. It becomes a shape.

  When the elastic member 104 has a shape that floats on both sides in the length direction in this way, the pressure for pressing the toner at both ends in the length direction becomes larger than the central portion, and the toner layers at both ends of the developing roller are not uniform, Density unevenness occurs at both ends. For this reason, the blade 101 is formed by joining the elastic member 104 to the highly rigid support member 105 by screwing, adhesive, welding, or the like, thereby keeping the elastic member straight and the contact pressure with the developing roller. Has been made constant in the longitudinal direction.

Further, as an improved technique related to the blade, for example, Patent Document 2 discloses a developer amount regulating member having an elastic layer that regulates the amount of charge on a support layer that regulates pressure, in the longitudinal direction. By forming the both ends in a shape that is curved in an arc shape on the elastic layer side, the pressure that presses the toner at both ends in the longitudinal direction of the developer amount regulating member is prevented from lowering than the center, and toner leakage occurs. A technique is disclosed that enables uniform application of toner at both ends where the above occurs.
JP 2001-117358 A Japanese Patent No. 3275226

  However, by simply joining the elastic member with the warp to the highly rigid support member, the warp in the resulting blade could not be sufficiently eliminated. In addition, as described in Patent Document 2, even in a technique in which the shape of the elastic member is intentionally warped without using a support member, a uniform toner application state is not necessarily obtained at both ends and the center of the blade. This is not a problem, and the toner layer at both ends of the developing roller may become thin due to the contact pressure at both ends becoming stronger than at the center, which causes density unevenness at both ends. Could not be solved sufficiently. Further, the warping of the elastic member deteriorates handling properties, and further deteriorates work efficiency for attaching the support member.

  Therefore, the object of the present invention is to make the contact pressure between the developer amount regulating blade and the developing roller uniform over the longitudinal direction, and obtain a good image without density unevenness in the longitudinal direction of the developer amount regulating blade, An object of the present invention is to provide a developer amount regulating blade excellent in work efficiency in the manufacturing process.

  As a result of intensive studies in view of the above problems, the present inventors have found that the above problems can be solved by making the amount of warping of the elastic member less than a certain value, and have completed the present invention.

  That is, the developer amount regulating blade of the present invention includes an elastic member in which a rubber portion is fixed to one end portion in the width direction of a thin strip-shaped leaf spring portion by integral molding along the longitudinal direction, and the elastic member. And a support member that sandwiches the other end portion in the width direction of the leaf spring portion along the longitudinal direction from both sides in the thickness direction, wherein the elastic member is used for the developer amount restriction blade The amount of warpage at one end when the manufactured integrally molded product is placed on a surface plate so that the center in the longitudinal direction of the leaf spring part lands and both ends warp to the rubber part side to approximately the same dimension. The measured value is 0 mm or more and less than 5.0 mm, the leaf spring part is made of stainless steel, the thickness of the leaf spring part is 0.08 to 0.12 mm, and the rubber part is silicone. It is made of rubber and the thickness of the rubber part 1.0 to 2.0 mm, the tensile elastic modulus at 10% stretching of the rubber part is 0.6 MPa or more and less than 2.0 MPa, and the elastic modulus and self-weight of the leaf spring part are the elastic modulus of the rubber part. It is characterized by winning.

  In the developer amount regulating blade of the present invention, the rubber portion preferably has a micro hardness of less than 70 °. More preferably, the oil content of the rubber part is 2.0% by weight or less, and the thickness of the elastic member is constant.

  According to the present invention, by making the amount of warping of the elastic member less than a certain value, the contact pressure with the developing roller can be made uniform, and a good image without density unevenness in the blade longitudinal direction can be obtained. Can do. At the same time, since the amount of warping of the elastic member is small, handling properties can be improved, and work efficiency for attaching the support member can also be improved.

Hereinafter, an embodiment of the developer amount regulating blade of the present invention will be described in detail.
FIG. 1 is a perspective view of a developer amount regulating blade. The developer amount regulating blade 1 includes an elastic member 4 in which a rubber portion 3 is fixed to one end portion in the width direction of the thin-plate-shaped leaf spring portion 2 by integral molding along the longitudinal direction, and a leaf spring portion 2. It consists of the supporting member 5 which clamps the other edge part of the width direction of a width direction along a longitudinal direction. FIG. 2 is a front view showing the elastic member taken out of them.

In FIG. 2, D represents the amount of warpage in the longitudinal direction of the elastic member 4 when the plate spring portion 2 side is left on the surface plate 6 as shown in the drawing. More specifically, D is an integrally molded product of the elastic member 4 manufactured for the developer amount regulating blade, and the center of the leaf spring portion 2 in the longitudinal direction is landed and both ends are substantially the same size. It is a value measured as the amount of warp at one end when it is placed on the surface plate 6 so as to warp. The present invention is characterized in that the warpage amount D of the elastic member 4 before being sandwiched by the support member is 0 mm or more and less than 5.0 mm, and the warpage amount D is preferably as close to 0 as possible. When the amount of warpage before being integrated with the support member is 5.0 mm or more, the amount of warpage of the elastic member (the amount of warpage of the blade) when the developer amount regulating blade is configured with the support member is increased. Accordingly, the contact pressure with respect to the developing roller at both ends of the blade becomes stronger than that at the central portion, and the toner layers at both ends of the image roller become thin. As a result, the image density at both ends becomes thin, and density unevenness occurs in the longitudinal direction.
It is preferable to be within the range of 2.0 mm.

  The length of the developer amount regulating blade is preferably about 200 to 230 mm in consideration of A4 plate correspondence.

  The rubber portion 3 is fixed to the leaf spring portion 2 by integral molding, but an adhesive layer may be provided between the leaf spring portion 2 and the rubber portion 3 as necessary. The leaf spring portion 2 can be formed of a metal or a resin. Examples of the metal include iron, copper, white, stainless steel, phosphor bronze, etc., and preferably have a thickness of 0 for controlling the pressing force to the developing roller. 0.08 to 0.12 mm.

  The rubber part 3 is made of isoprene rubber, butadiene rubber, styrene / butadiene rubber, acrylonitrile / butadiene rubber, chloroprene rubber, ethylene / propylene rubber, ethylene / propylene terpolymer (EPDM), butyl rubber, acrylic rubber, chlorosulfone. Rubber materials such as chlorinated polyethylene, silicone rubber, fluoro rubber, polyether rubber, epichlorohydrin rubber, urethane rubber, polyurethane, silicone, polystyrene / polybutadiene block polymer, polyolefin, polyethylene, chlorinated polyethylene, ethylene / vinyl acetate copolymer And the like, and silicone rubber is preferably used. Moreover, it is preferable that the thickness of the rubber part 3 exists in the range of 1.0-2.0 mm.

  In addition, it is preferable that the tensile elasticity modulus (Young's modulus) at the time of 10% extending | stretching of the rubber part 3 at room temperature is less than 2.0 MPa, More preferably, it is 0.5-1.8 MPa. More preferably, it is 0.6 MPa or more. Thereby, since the elastic modulus and self-weight of a leaf | plate spring part are superior to the elastic modulus of rubber | gum, it becomes possible to make the curvature amount of an elastic member small. In the present invention, the tensile elastic modulus of the rubber part 3 is a value measured by peeling the rubber part 3 of the elastic member 4 obtained by integral molding from the leaf spring part 2. Further, the micro hardness of the rubber part 3 is preferably 44 ° or more and less than 70 °, and the micro hardness is measured by using a micro hardness meter MD-1 type (type A) manufactured by Kobunshi Keiki Co., Ltd. Measurements can be made.

  Further, the rubber part 3 can contain a filler such as carbon, a plasticizer such as oil, or the like, if necessary. In this case, the oil content of the rubber part is 2.0% by weight or less, particularly preferably close to 0, and the volume compressed by using the rubber part having an elastic modulus of less than 2.0 MPa. Even when becomes larger, contamination of the developing roller due to oil seepage from the rubber member can be prevented. The oil content includes oil contained in the polymerization process.

  The support member 5 needs to be formed of a highly rigid material. Specifically, for example, the same metal as that used for the plate spring portion 2 described above can be used. This thickness is about 1.0 to 2.0 mm.

  When manufacturing the elastic member, if the rubber part is a thermosetting material such as silicone rubber, liquid silicone rubber is injected into a high-temperature mold cavity preloaded with a leaf spring part. Then, the elastic member is formed by cooling integrally with the leaf spring portion. If the rubber part is thermoplastic, the rubber material heated and fluidized in the same manner is injected into the mold cavity loaded with the leaf spring part, and then integrally with the leaf spring part. The elastic member is formed by cooling and solidifying. A preferred example of manufacturing the elastic member will be described below. FIG. 3A is a cross-sectional view showing a two-cavity mold for molding the elastic member 4, and FIG. 3B is a cross-sectional view showing the AA cross section of FIG. Although FIG. 3 shows a two-ply mold, it is not particularly limited to two-pick and may be a single ply.

The mold 11 includes a main mold 13 and an insert mold 14 that are spaced apart and displaced along an arrow T ₃ , and a sprue plate that is relatively spaced and displaced along the arrow T ₁ with respect to the molds 13 and 14. The sprue plate 15 is provided with a first sprue 22 and a runner 23 for allowing the injected liquid silicone rubber to pass therethrough. The main mold 13 corresponds to the rubber portion 3. A cavity 17 and a gate 25 and a second sprue 24 for injecting liquid silicone rubber into the cavity 17 are provided. The insert mold 14 is provided with a recess 21 for arranging the leaf spring portion 2.

In the figure, reference numeral 12 denotes an injection head of a molding machine for injecting liquid silicone rubber, and reference numeral 19 denotes a liquid silicone rubber conduit. The injection head 12 is relatively spaced and displaced along the arrow T ₂ with respect to the sprue plate 15, and the liquid silicone rubber conduit 19 and the first sprue 22 communicate with each other at a position where the injection head 12 contacts the sprue plate 15. Are arranged as follows.

  The main mold 13, the insert mold 14, the sprue plate 15 and the injection head 12 are arranged separately from each other. First, the leaf spring portion 2 is arranged in the recess 21 of the insert mold 14.

  Next, the main mold 13 and the insert mold 14 are moved closer to each other, and the sprue plate 15 is moved closer to the molds 13 and 14 to close the mold 11. Next, the injection head 12 is brought into contact with the sprue plate 15, and in this state, liquid silicone rubber is injected. The injected liquid silicone rubber sequentially passes through the liquid silicone rubber conduit 19, the first sprue 22, the runner 23, the second sprue 24 and the gate 25 and is injected into the cavity 17. Thereafter, the elastic member 4 can be obtained by thermosetting.

Hereinafter, the present invention will be described in detail according to examples.
Example 1
As the leaf spring portion 2, a 1.5 mm thick silicone rubber (tensile elasticity when stretched by 10%) is formed along one longitudinal end of a 0.1 mm thick stainless steel metal foil (SUS301) in the width direction. A rubber portion 3 having a rate of 0.6 MPa and a micro hardness of 44 ° was formed by integral molding to obtain an elastic member 4.

  In the production of the elastic member 4, liquid silicone rubber was injected into a high-temperature mold shown in FIG.

  As shown in FIG. 2, the obtained elastic member 4 supports the elastic member 4 as shown in FIG. 1 and the amount of warpage D of the elastic member 4 when the plate spring portion 2 is placed downward. The amount of warpage of the developer amount regulating blade 1 obtained by integrating with the member 5 (galvanized steel sheet) is shown in Table 1 below. In addition, the tensile elasticity modulus at the time of 10% extending | stretching of the rubber part 3 is the value which cut out the sample of length 50-100mm from the rubber part 3 peeled off from the leaf | plate spring part 2, and measured at room temperature with the tensile tester (below). The same applies to the above).

Example 2
An elastic member 4 was produced in the same manner as in Example 1 except that the rubber part 3 was formed as a silicone rubber having a tensile elastic modulus of 1.8 MPa when stretched by 10% and a micro hardness of 68 °.

  The amount of warping of the elastic member and the amount of warping of the developer amount regulating blade 1 measured in the same manner as in Example 1 are shown in Table 1 below.

Comparative Example 1
An elastic member 4 was produced in the same manner as in Example 1 except that the rubber part 3 was formed as a silicone rubber having a tensile elastic modulus of 2.0 MPa at 10% stretching and a micro hardness of 70 °.

  The amount of warping of the elastic member and the amount of warping of the developer amount regulating blade 1 measured in the same manner as in Example 1 are shown in Table 1 below.

Comparative Example 2
An elastic member 4 was produced in the same manner as in Example 1 except that the rubber part 3 was formed as a silicone rubber having a tensile elastic modulus of 3.5 MPa at 10% stretching and a micro hardness of 79 °.

  The amount of warping of the elastic member and the amount of warping of the developer amount regulating blade 1 measured in the same manner as in Example 1 are shown in Table 1 below.

  The developer amount regulating blades obtained in the examples and comparative examples were mounted on a commercially available printer, the printing operation was repeated, and a durability test of 20000 sheets of A4 paper was performed. The results were evaluated for image quality and are shown in Table 1 below. In addition, the oil content of the rubber part and the presence or absence of contamination of the developing roller due to the oil seepage from the rubber member are shown.

  As shown in Table 1, good images could be obtained in Examples 1 and 2 in which the amount of warping of the elastic member was 0.6 mm and 4.0 mm, but the amount of warping of the elastic member was 5. In Comparative Examples 1 and 2 with 0 mm and 10.0 mm, the density decreased at both ends of the image, resulting in density unevenness. Further, it was confirmed that contamination of the developing roller can be prevented by setting the oil content to 2.0% by weight or less.

  The present invention can be applied to a developer amount regulating blade used in an electrophotographic or electrostatic recording type image forming apparatus such as a copying machine, a facsimile, or a printer.

FIG. 3 is a perspective view of a developer amount regulating blade of the present invention. It is a front view which shows the elastic member of this invention. It is sectional drawing which shows the metal mold | die for 2 picking which shape | molds the elastic member of this invention. FIG. 10 is a cross-sectional view illustrating a state in which a conventional developer amount regulating blade is attached to an image forming apparatus. It is the front view and sectional drawing which show the conventional developer amount regulation blade.

Explanation of symbols

1 101 Developer amount regulating blade (blade)
2 102 Leaf spring portion 3 103 Rubber portion 4 104 Elastic member 5 105 Support member 6 Surface plate 11 Mold 12 Injection head 13 Main die 14 Insert die 15 Sprue plate 17 Cavity 19 Liquid silicone rubber conduit 21 Recess 22 First sprue 23 runner 24 second sprue 25 gate 106 developing roller

Claims (4)

An elastic member in which a rubber portion is fixed to one end portion in the width direction of the thin strip-shaped leaf spring portion by integral molding along the longitudinal direction, and the other end portion in the width direction of the leaf spring portion of the elastic member In a developer amount regulating blade comprising a support member that is sandwiched from both sides in the thickness direction along the longitudinal direction,
The elastic member is an integrally molded product manufactured for the developer amount regulating blade on the surface plate so that the center in the longitudinal direction of the leaf spring portion lands and both end portions warp to the rubber portion side to approximately the same size. The value measured as the amount of warping at one end when placed is 0 mm or more and less than 5.0 mm,
The leaf spring part is made of stainless steel, and the thickness of the leaf spring part is 0.08 to 0.12 mm;
The rubber part is made of silicone rubber , and the rubber part has a thickness of 1.0 to 2.0 mm;
Wherein when stretched 10% in the tensile modulus of the rubber portion is Ri 2.0MPa less der than 0.6 MPa,
A developer amount regulating blade , characterized in that the elastic modulus and its own weight of the leaf spring portion are superior to the elastic modulus of the rubber portion . The developer amount regulating blade according to claim 1, wherein the rubber portion has a micro hardness of 44 ° or more and less than 70 °.   The developer amount regulating blade according to claim 1 or 2, wherein the oil content of the rubber part is 2.0 wt% or less.   The developer amount regulating blade according to claim 1, wherein the elastic member has a constant thickness.

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