JP2009090496A - Method for manufacturing blade for office automation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a blade for office automation capable of suppressing a protruded rubber from a runner from being generated in manufacturing the blade for office automation and prevent even a part of the protruded rubber from remaining when tearing up the runner rubber. <P>SOLUTION: The injection pressure during injecting an elastomer material is not larger than the pressure P<SB>0</SB>in the term S<SB>0</SB>from the time t<SB>1</SB>when at least a leading part of the elastomer material reaches the runner on a plate to the time t<SB>2</SB>when the leading part finishes passing through the runner on the plate, and the injection pressure is a pressure higher than the pressure P<SB>0</SB>in the term S<SB>1</SB>from the time t<SB>0</SB>after the start of injection to the time t<SB>1</SB>, and in the term S<SB>2</SB>from the time t<SB>2</SB>to the time t<SB>4</SB>thereafter. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an OA blade used in an OA image forming apparatus such as a developer regulating blade, and more particularly to a method capable of reducing burrs during injection molding.

  In electrophotographic or electrostatic recording type image forming apparatuses such as copying machines, facsimiles, printers, etc., particularly for color, there is a method in which a non-magnetic developer is charged and the developer is transferred to the photosensitive drum by the charge. In this system, the developer is carried on the outer periphery of the developing roller, and the amount of developer supplied by the rotating developing roller is attached in a posture facing the outer peripheral surface, and the developer amount is regulated. The blade is regulated by the blade and the developer is triboelectrically charged by the blade.

  As the developer amount regulating blade, an elastomer member having sufficient flexibility to form a gap through which the developer passes and characteristics necessary for frictionally charging the developer are bonded to a thin metal plate. Often used.

  Further, in the image forming apparatus, a cleaning blade for cleaning the surface of the photosensitive drum is one in which an elastomer member is bonded to one side of a thin metal plate, and the elastomer member is pressed against the rotating photosensitive drum. Thus, the developer attached to the photosensitive drum is scraped off.

  A blade (hereinafter referred to as “OA blade” in the present specification) having a structure in which an elastomer member is bonded to the metal plate, such as a developer amount regulating blade and a cleaning blade, which is attached to an OA apparatus is conventionally known. Then, an injection molding method is used to inject an elastomer member into a mold cavity, and the elastomer member is adhered to a metal plate with an adhesive previously disposed in the mold to be molded (for example, , See Patent Document 1).

  As an example of such an OA blade, FIG. 1 is an attachment view showing a state in which a developer amount regulating blade is mounted on the apparatus. The developer amount regulating blade 1 includes a thin metal plate 2 and one side thereof. It is composed of an elastomer member bonded to the surface, for example, a rubber member 3, and the rubber member 3 is arranged in a posture in contact with the peripheral surface 5 a of the rotating developing roller 5 or in a posture having a slight gap with the peripheral surface 5 a. It functions to regulate the layer thickness of the developer 4 on the developing roller peripheral surface 5a.

  FIG. 2 is a cross-sectional view showing a mold for injection molding the developer amount regulating blade 1. The mold 10 includes a metal plate 2 disposed in a cavity 11 surrounded by an upper mold 12 and a lower mold 13. The material for forming the rubber member 3 is passed through the on-plate runner 14 formed on a part of the surface of the metal plate 2, passed through the gate 15 and the tab 16, and injected into the cavity 11. After filling with the material for forming the member 3, this is formed by curing by applying heat.

FIG. 3 is a sectional view showing the developer amount regulating blade 1 formed by such a method in a state before finishing, and FIG. 4 is a plan view showing the developer amount regulating blade 1 as a mold. Immediately after being taken out from the metal plate 2, the metal plate 2 has a rubber member 3, a runner rubber 24 corresponding to the on-plate runner 14, a protruding rubber 28 associated with the runner rubber 24, a gate 16 and a tab 16, as shown in the figure. Although the gate rubber 25 and the tab rubber 26 corresponding to each are formed together, the runner rubber 24, the protruding rubber 28, and the gate rubber 25 are formed in a portion of the metal plate 2 where the adhesive is not applied. By removing the runner rubber 24 by hand, these rubbers 25 and 28 can also be removed together.
JP 2002-61953 A

  However, as shown in the figure, when the rubber leak range from the gap 18 between the upper mold 12 and the lower mold 13 is wide and the protruding rubber 28 reaches the edge 2a of the metal plate or the portion where the adhesive is applied. Even if the runner rubber 24 is peeled off, a part of the protruding rubber 28 as illustrated as the portion S in FIG. 1 may remain, and in this case, it is very difficult to remove the remaining rubber. It took a lot of time. In order to improve this, it is important to suppress leakage from the gap 18 between the upper mold 12 and the lower mold 13, but no countermeasure has been found so far.

  The present invention has been made in view of such a problem, and when the runner rubber 24 is peeled off by suppressing the spread of the protruded rubber 28 protruding from the runner 14, a part of the protruded rubber 28 remains. It is an object of the present invention to provide a method for manufacturing an OA blade that can be eliminated.

<1> is a method in which an elastomer material is injected through a plate runner formed on a part of a surface of the metal plate into a cavity in which the metal plate is disposed, thereby injecting the metal plate and one side thereof. In the manufacturing method of the blade for OA which forms the blade for OA consisting of the elastomer member adhered to the surface,
The injection pressure at the time of injecting the elastomer material is a period from at least a time t ₁ when the leading portion of the elastomer material reaches the on-plate runner to a time t ₂ when the leading portion finishes passing through the on-plate runner. and S ₀ in the pressure P ₀ or less, the period S ₁ from the time t ₀ after the start of injection to the said time t _1, the period S ₂ from the time t ₂ to time t ₄ later than this, the pressure P This is a method for manufacturing an OA blade having a pressure higher than ₀ .

<2> uses liquid silicone rubber as the elastomer material in <1>, and the injection pressure range in the period S ₀ when using this is 7 to 9 MPa, and the injection pressure pattern in the period S ₂ is This is a method for manufacturing an OA blade that injects the elastomer material so as to have a pattern that maintains a constant pressure P ₂ in the range of 18 to 30 MPa after monotonously increasing from the pressure at time t ₂ .

<3>, in <2>, the maximum pressure P ₁ in the period S ₁ is a method for manufacturing OA blade that emits the elastomeric material so as to be 12～30MPa.

<1> According to <1>, when the leading part of the highly fluid elastomer material passes through the above-mentioned runner on the plate where burrs are likely to occur, the pressure is as low as P ₀ or less. On the other hand, after the top part of the elastomer material passes through the runner on the plate, the injection pressure is set to a pressure higher than P ₀ to increase the filling rate of the material in the cavity and ensure the transfer performance. At this time, the material on the surface of the runner on the plate is already hardened, and even if high pressure is applied here, the protrusion from there is little.
In the period S ₁ from time t ₀ to time t ₁ , the injection pressure is set to a pressure higher than P ₀ , so if this pressure is low, air is entrained and the surface of the elastomer member becomes rough. Can be prevented.

According to <2>, when liquid silicone rubber is used as the elastomer material, the injection pressure range in the period S ₀ is 7 to 9 MPa, and the injection pressure pattern in the period S ₂ increases monotonously from the pressure at the time t ₂ . After that, the pattern that maintains the constant pressure P ₂ is used, so it is possible to more reliably prevent the protrusion from the on-plate runner and achieve excellent transfer performance, and the injection pressure range in the period S ₀ Is less than 7MPa, the injection rate is slower than the rate at which the reaction proceeds, so there is a risk of short-circuiting in a state where the end is not molded, whereas when this exceeds 9MPa Will cause burrs from the runner.

According to <3>, since the maximum pressure P ₁ in the period S ₁ is set to ₁₂ to 30 MPa, surface roughness of the elastomer member can be more reliably suppressed, and the maximum pressure P ₁ is set to less than 12 MPa. In this case, since the injection speed is slower than the reaction speed, the solidified material may flow in the mold, resulting in surface roughness. It becomes easier to burr.

Embodiments of the present invention will be described with reference to the drawings. In the present invention, as shown in a graph in FIG. 5 where the horizontal axis represents the elapsed time from the start of injection and the vertical axis represents the injection pressure, the injection pressure when injecting the elastomer material is at least the start of the elastomer material. In a period S ₀ from time t _{1 at which the} portion reaches the on-plate runner to time t _{2 at} which the leading portion finishes passing through the on-plate runner, the pressure is set to ₀ or less, and from time t ₀ after the start of injection to the time the period S ₁ until t _1, the period S ₂ from the time t ₂ to time t ₄ later than this, is characterized in that a pressure higher than the pressure P _0.

In the above description, FIG. 6 schematically shows the leading portion of the elastomer material passing through the flow path in the mold, the position at time t ₁ in FIG. 6, and the position at time t ₂ in FIG. Further, the leading portion 19 of the elastomer material injected from the head 8 of the injection machine has a flow path provided in the mold 10 formed in a portion without the metal plate 2 (on the non-plate), the runner 17 and the plate The runner 14, the gate 15, and the tab 16 are sequentially passed and injected into the cavity 11, but the leading portion 19 of the elastomeric material is at the entrance A1 of the on-plate runner 14 at time t ₁ and at time t ₂ . is situated respectively at the outlet A2 of plate runner 14, the present invention is, leading portion 19 of the elastomeric material moving as described above for a period S ₀ to proceed to FIG 7. FIG 6 Injection pressure as compared to the period of one behind this period S ₀ is characterized in that it is suppressed low.

  Then, by injecting the elastomer material with such an injection pressure pattern, the pressure is reduced while the leading portion 19 of the elastomer material passes through the on-plate runner 14 where burrs are likely to occur, thereby suppressing protrusion. If the leading portion 19 of the material passes through the outlet A2 of the on-plate runner 14, the material on the on-plate runner surface 14 has already hardened at this time. Conversely, by making this high pressure, it is possible to eliminate the unfilled portion in the cavity and contribute to the transfer performance of the cavity surface to the product.

  In addition, said injection pressure is a pressure added to material when pressing a material with a screw in the cylinder of an injection machine.

  Liquid silicone rubber is used as the elastomer material, and this liquid silicone rubber is injected with multiple different injection pressure patterns, and the quality of the protrusion from the runner on the plate (runner flash on the plate) and other product appearance is judged visually. did. The filling time from the start of injection to the end of filling was also measured. The injection pressure conditions and determination results are shown in Table 1.

Note that “A” in the pressure pattern is the pattern shown in FIG. 5, “B” means the pattern shown in FIG. 8, and “C” means the pattern shown in FIG. Further, regarding the determination of runner flash on the plate, “◯” represents “good”, “x” represents “not good”, and “xx” represents “very bad”. In addition, regarding the appearance of the product, all items that were not “◯” were “x”.

  The developer regulating blade 1 has been described above as an example, but the above description can be applied to other OA blades such as a cleaning blade having the same configuration.

FIG. 6 is a schematic view of attachment showing a developer regulating blade. It is sectional drawing which shows the injection mold for developer control blade formation. It is sectional drawing of the developer control blade taken out from the metal mold | die. It is a top view of the developer control blade taken out from the mold. It is a graph which shows the injection pressure pattern in the manufacturing method of the blade for OA of the embodiment concerning the present invention. It is a schematic diagram showing the position at the time t ₁ of the leading portion of the elastomer material that passes through the flow path in the mold. The leading portion of the elastomeric material passing through the flow path in the mold is a schematic diagram showing the position at time t _2. It is a graph which shows the pressure pattern corresponding to Comparative Examples 3-6. It is a graph which shows the pressure pattern corresponding to the comparative examples 1 and 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Developer control blade 2 Metal plate 3 Rubber member 4 Tab 5 Developing roller 5a Developing roller peripheral surface 8 Injection machine head 10 Mold 11 Cavity 12 Upper mold 13 Lower mold 14 Plate runner 15 Gate 16 Tab 19 Leading elastomer material Part 24 Runner rubber 25 Gate rubber 26 Tab rubber 28 Extruded rubber

Claims (3)

The elastomeric material was bonded to the metal plate and one side of the metal plate by injecting it through a plate runner formed on a part of the surface of the metal plate into the cavity where the metal plate was placed. In the manufacturing method of the blade for OA which forms the blade for OA composed of the elastomer member,
The injection pressure at the time of injecting the elastomer material is a period from at least a time t ₁ when the leading portion of the elastomer material reaches the on-plate runner to a time t ₂ when the leading portion finishes passing through the on-plate runner. and S ₀ in the pressure P ₀ or less, the period S ₁ from the time t ₀ after the start of injection to the said time t _1, the period S ₂ from the time t ₂ to time t ₄ later than this, the pressure P OA blade manufacturing method with a pressure higher than ₀ . As the elastomer material, liquid silicone rubber was used, and when this was used, the injection pressure range in the period S ₀ was 7 to 9 MPa, and the injection pressure pattern in the period S ₂ monotonically increased from the pressure at the time t ₂ . The method for manufacturing an OA blade according to claim 1, wherein the elastomer material is injected so as to have a pattern that maintains a constant pressure P ₂ in a range of 18 to 30 MPa. Method for manufacturing OA blade of claim 2, the maximum pressure P ₁ in the period S ₁ is emitted the elastomeric material so as to be 12～30MPa.

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