JP2013233776A - Mold for producing developing blade and method for producing developing blade using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for producing a developing blade which can surely fill extension parts even when the developing blade has such a complicated shape that the extension parts are arranged at both ends of the blade beyond a notch part for circulating a developer and can improve a product yield, and to provide a method for producing the developing blade with the use of the mold.SOLUTION: In a mold for producing a developing blade, a cavity corresponding to the shape of a blade member is provided, a gate part for injecting a material is formed on a side on which a first extension part is formed, on the side of an end side part of a cavity part which forms a second extension part located at a position opposite to the first extension part in the longitudinal direction, an air vent groove is formed in communication with the outside, when the length along the end side part of the second extension part is L and the width along the end side part of the air vent groove is Wa, the width Wa of the air vent groove is L/3 or below and a central position P dividing the width Wa of the air vent groove into two parts in the width direction is positioned at L/2 or on the side of a notch part for circulating a developer from L/2.

Description

  The present invention relates to a mold for manufacturing a developing blade, and more particularly to a mold for forming a developing blade used in a developing device of an electrophotographic image forming apparatus such as a laser printer, a copying machine, and a facsimile machine.

  An image forming apparatus using an electrophotographic image forming process includes a developing device for developing a latent image on a photosensitive drum. As this developing device, for example, as shown in FIG. 8, there is known a developing device 51 having a structure including a hopper 52, a developing roller 53, a rotatable stirring plate 54, and a developing blade 55 (see FIG. 8). Patent Document 1).

  In such a developing device 51, the developer 56 stored in the hopper 52 is supplied to the developing roller 53 side by a rotating stirring plate 54, and the developing roller is caused by frictional charging between the developing blade 55 and the developing roller 53. The developer is uniformly supported in a thin layer on the peripheral surface of 53, and excess developer not supported is returned into the hopper 52. Then, the development is carried out by transferring the developer 56 from the developing roller 53 to the photosensitive drum 57 on which the latent image is formed.

  In such development processing, in order to prevent excess developer scraped off by the development blade 55 from leaking out of the development region in the longitudinal direction of the development roller 53 without returning into the hopper 52, the following In Patent Documents 2 to 4, for example, as shown in FIG. 9, a support member 112 and a blade member 115 disposed along one end side portion 112A of the support member 112 are provided and supported. The member 112 has a developer circulation notch 113 in the vicinity of both end portions of the end side portion 112A, and the blade member 115 extends beyond the developer circulation notch portion 113 at both ends of the end side portion 112A. There has been proposed a developing blade 55 that extends to the vicinity of the portion, and the blade member 115 has a notch 116 corresponding to the developer circulation notch 113.

JP 2003-43812 A JP 2008-216275 A JP 2009-122384 A JP 2010-110949 A

  However, in such a complicated shape of the developing blade, it is difficult to sufficiently fill the corners 114a and 114b of the extending portion 114 disposed at both ends of the blade after injection molding with a molding material such as rubber, and the edge shape. There is a tendency that a problem that the above becomes unclear (short) is likely to occur (see FIG. 10).

  The present invention has been invented based on such a situation, and the object thereof is to have a complicated shape having extended portions arranged beyond the developer circulation notches at both ends of the blade as described above. It is an object of the present invention to provide a mold for manufacturing a developing blade that can reliably fill the extended portion even with the developing blade of the above, and improve the product yield, and a method for manufacturing the developing blade using the same. .

  In Patent Document 3 and Patent Document 4, there are descriptions relating to the gas vent portion and rough surface processing on the set surface of the mold plate, respectively. It cannot be said that measures are being taken.

  In order to solve the above-described problems, according to the present invention, a blade member is formed on a long support member along the longitudinal direction of one end side portion of the support member. A developer circulation notch is provided in the vicinity of both end portions in the longitudinal direction of the side portion, and the blade member extends to both ends of the longitudinal direction beyond the developer circulation notch portion, respectively. And a developing blade having a first extending portion and a second extending portion extending to the vicinity of both end portions in the longitudinal direction of the end side portion. And a cavity corresponding to the shape of the blade member, and a gate portion for injecting material is formed on the side where the first extending portion is formed, opposite to the first extending portion in the longitudinal direction. The end side of the cavity part forming the second extension in position The air vent groove is formed in communication, the length of the second extending portion along the end side portion is L, and the width of the air vent groove along the end side portion is Wa. In this case, the width Wa of the air vent groove is L / 3 or less, and the center position P that bisects the width Wa of the air vent groove in the width direction is more than L / 2 or L / 2. It is configured to be set in an area δ located on the notch side.

  Further, as a preferable aspect of the developing blade manufacturing mold of the present invention, the width Wa of the air vent groove is formed so as to be within the area δ on the developer circulation notch portion side than L / 2. .

  As a preferred embodiment of the developing blade manufacturing mold of the present invention, the air vent groove has a width Wa of L / 20 to L / 6.

  As a preferred embodiment of the developing blade manufacturing mold of the present invention, the depth H of the air vent groove is configured to be 0.03 to 0.07 mm.

  Further, as a preferred embodiment of the developing blade manufacturing mold of the present invention, the length L along the end side portion of the second extending portion is configured to be 0.8 to 1.5 mm.

  Further, as a preferred embodiment of the developing blade manufacturing mold of the present invention, the mold is mounted on the lower mold for positioning and mounting the long support member, and on the lower mold An upper die attached to the elongated support member, and the upper die has a cavity corresponding to the shape of the blade member and a gate portion and an air vent for injecting material It is configured to have a groove.

  As a preferred embodiment of the developing blade manufacturing mold of the present invention, the outermost position of the air vent groove is a gap generated when the lower mold and the upper mold are combined through a long support member. It is arranged to be communicated with.

  Further, as a preferred embodiment of the developing blade manufacturing mold of the present invention, a structure for evacuating the periphery of the cavity according to the shape of the blade member is not provided.

  Further, as a preferred embodiment of the mold for producing a developing blade of the present invention, the cavity is set to be multi-cavity so that a plurality of developing blades can be molded simultaneously.

  The developing blade manufacturing method of the present invention is configured to manufacture a developing blade by injecting a material into the above-described developing blade manufacturing mold.

  In a preferred embodiment of the developing blade manufacturing method of the present invention, the material is a rubber material.

  As a preferred embodiment of the developing blade manufacturing method of the present invention, the rubber material is a liquid silicone rubber.

  Moreover, the preferable aspect of the manufacturing method of the image development blade of this invention is comprised from the injection molding method.

  Moreover, as a preferable aspect of the manufacturing method of the developing blade of this invention, it is comprised so that the viscosity of the injected liquid silicone rubber may be 50-1000 P (poise).

  In the developing blade manufacturing mold of the present invention, a blade member is formed on a long support member along the longitudinal direction of one end side portion of the support member, and the support member is on the end side. The blade member has a notch for circulating the developer in the vicinity of both end portions in the longitudinal direction of the part, and the blade member extends beyond the notch for circulating the developer at both ends in the longitudinal direction. A mold used for manufacturing a developing blade having a first extension part and a second extension part extended to the vicinity of both end parts in the longitudinal direction of the end side part, wherein the mold is A cavity corresponding to the shape of the blade member is provided, and a gate portion for injecting material is formed on the side where the first extension portion is formed, and is opposite to the first extension portion in the longitudinal direction. On the end side portion side of the cavity portion forming the second extending portion at The air vent groove is formed in communication, the length along the end side portion of the second extending portion is L, and the width along the end side portion of the air vent groove is Wa. In this case, the width Wa of the air vent groove is equal to or less than L / 3, and the center position P that bisects the width Wa of the air vent groove in the width direction is less than L / 2 or L / 2. Since it is set so as to be located on the notch portion side, even if the developing blade has a complicated shape and has an extending portion arranged at both ends of the blade beyond the notch portion for developer circulation, the extending portion is not provided. Filling can be ensured, and the product yield can be improved.

FIG. 1 is a plan view showing an embodiment of a developing blade that is a molding object manufactured using the mold of the present invention. 2A is a cross-sectional view taken along the line II of FIG. 1, FIG. 2B is a cross-sectional view taken along the line II-II of FIG. 1, and FIG. FIG. 3 is a cross-sectional view taken along line III. FIG. 3 is a plan view simply and schematically showing a state in which the blade member is filled from the gate portion at one end to the other end in the cavity corresponding to the shape of the blade member, and finally the material of the blade member is It is the elements on larger scale of the 2nd extension part which flows in. FIG. 4 is a plan view schematically showing the mold structure. The shape of the cavity in which the blade member is filled (substantially the same as the shape of the blade member) is indicated by a dotted line. Although the support member 20 inserted in the mold is originally hidden and cannot be seen, it is indicated by a solid line for convenience in order to clarify the shape of the cavity. FIG. 5 is an end view taken along line IV-IV of the mold structure shown in FIG. FIG. 6 is an end view taken along line VV of the mold structure shown in FIG. FIG. 7 is a drawing showing the positions and widths of the air vent grooves 40 that are specifically arranged in the experimental example, and in particular, the length along the end side of the second extending portion is L, and the air It is drawing which showed the width along the end side part of a vent groove clearly with respect to Wa. A-I, A-II, A-III; B-I, B-II, B-III; C-I, C-II, C-III; D-I, D-II, D-III; E- I, E-II, E-III; F-I, F-II, F-III; GI, G-II, G-III; J1, J2; K1, K2, K3, K4; The width Wa of the formed air vent groove 40 is shown. It is a figure which shows an example of the structure of a developing device. It is a top view which shows an example of a developing blade. FIG. 10 is a view for visually explaining a conventional problem, and is an enlarged plan view in the vicinity of an extended portion of a developing blade.

  Hereinafter, a plurality of embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the form demonstrated below, In the range which does not deviate from a technical thought, it can implement in various deformation | transformation. In the accompanying drawings, the vertical and horizontal scales may be exaggerated for the sake of explanation, and the actual scales may differ.

  The present invention relates to a developing blade manufacturing die and a developing blade manufacturing method using the same. First, the form and the like of the developing blade to be molded and manufactured will be described with reference to FIGS.

<Description of development blade>
FIG. 1 is a plan view showing an embodiment of a developing blade manufactured (molded) using the mold of the present invention. 2A is a cross-sectional view taken along the line II of FIG. 1, FIG. 2B is a cross-sectional view taken along the line II-II of FIG. 1, and FIG. FIG. 3 is a cross-sectional view taken along line III. FIG. 3 is a plan view simply and schematically showing a state in which the blade member is filled from the gate portion at one end to the other end in the cavity corresponding to the shape of the blade member, and finally the material of the blade member is It is the elements on larger scale of the 2nd extension part which flows in.

  As shown in FIG. 1, the developing blade 10 to be molded and manufactured according to the present invention has a blade member 30 formed of an elastic member on a long support member 20. In FIG. 1, the blade member 30 is displayed with dots (points) so that the existence thereof is clear.

  As shown in FIG. 1, the blade member 30 is formed along the longitudinal direction of one end side portion 2 </ b> A of the support member 20. The support member 20 has a developer circulation notch 23 in the vicinity of both end portions in the longitudinal direction of the end side portion 2A. The blade member 30 includes a blade cutout portion 33 formed along the developer circulation cutout portion 23, and extends at both ends in the longitudinal direction beyond the developer circulation cutout portion 23. A first extending portion 35 and a second extending portion 36 are provided extending to the vicinity of the end portions on both sides in the longitudinal direction of the end side portion 2A.

  The material of the support member 20 constituting the developing blade 10 is not particularly limited. For example, a metal substrate made of stainless steel such as SUS301 or SUS304, phosphor bronze for springs such as C5210, a ceramic substrate, PC (polycarbonate), Examples thereof include a resin substrate such as PBT (polybutylene terephthalate). Moreover, the thickness of the support member 20 can be about 0.1 mm if it is stainless steel, for example.

  The developer circulation notch 23 formed in the support member 20 removes the excess developer existing between the developing blade 10 and the development roller from the opposite surface of the support member 20 (via the support member 20. To the surface opposite to the roller) for efficient circulation and collection in the hopper. The size and shape of the developer circulation notch 23 can be set as appropriate. For example, in the case of a rectangular notch, the width is 1 to 5 mm and the depth is 0.5 to 2. It can be set within a range of 5 mm.

  Further, the support member 20 includes a plurality of hole portions 14 along the end side portion 2B which is the other end facing the end side portion 2A. The holes 14 can be arbitrarily set for mounting, positioning, and the like, and are not limited to the illustrated form and number.

  The material of the blade member 30 constituting the developing blade 10 is not limited, and examples thereof include silicone rubber, nitrile rubber, fluorine rubber, urethane rubber, epichlorohydrin rubber, and hydrogenated nitrile rubber. As shown in FIGS. 2A to 2C, the blade member 30 has a slightly curved contact area with the developing roller. The shape of the blade notch 33 included in the blade member 30 is not particularly limited as long as the developer circulation notch 23 included in the support member 10 is exposed without being blocked. For example, the blade cutout portion 33 may have the same shape as the developer circulation cutout portion 23. Further, it may be slightly larger than the developer circulation notch 23 (for example, the width is within 1 mm and the support member 10 is exposed to the notch 33).

  In such a developing blade 10, of the excess developer scraped off from the developing roller, the excess developer existing between the developing blade 10 and the developing roller without falling into the hopper is not circulated in the developer. It is sent to the opposite surface of the support member 20 by the notch 23 for use, and then falls into the hopper and efficiently circulated and recovered. A first extending portion 35 and a second extending portion 36 are formed at both ends of the blade member 30 in the longitudinal direction (the direction indicated by the arrow a in FIG. 1) beyond the developer circulation notch 23. Therefore, the developer existing between the developing blade 10 and the developing roller is prevented from leaking out of the developing region in the longitudinal direction of the developing blade 10.

  As described above, the first extending portion 35 and the second extending portion 36 extend beyond the developer circulation notch 23 and both ends of the blade member 30 in the longitudinal direction (the direction indicated by the arrow a in FIG. 1). Are approximately the same size. In the present invention, when the blade member 30 is molded, the side close to the gate portion g (see FIG. 1) is referred to as a first extending portion 35 for convenience and is located far from the gate portion g, and finally the blade member. For convenience, the side on which 30 materials flow is considered to be referred to as a second extending portion 36.

  In FIG. 1, the second extending portion 36 is disposed on the left side position, and the first extending portion 35 is disposed on the right side. In FIG. 1, the gate portion g may be disposed near the left end, and the second extending portion 36 and the first extending portion 35 may be interchanged formally.

  The size of the first extending portion 35 and the second extending portion 36 is L when the length along the end side portion 2A is L and the back region length is D as shown in FIGS. = 0.8 to 1.5 mm, and D = 1.0 to 2.0 mm.

  Note that reference numeral 30 a shown in FIGS. 1 and 2 is a thin rectangular piece (skirt portion) that constitutes a part of the blade member 30. The small piece portion 30a is normally formed at a position where it does not come into contact with the developing roller as shown in the figure. For example, a gate is a place where a material flows into the small piece portion 30a first when the blade member 30 is formed. Cavity No. in the case of providing a part g or taking multiple pieces. It is possible to attach a symbol for identifying

<Description of mold for developing blade>
As shown in FIGS. 3 to 6, the developing blade manufacturing mold according to the present invention includes a cavity Cv corresponding to the shape of the blade member 30, and the side of the cavity portion 35 ′ that forms the first extending portion 35. In addition, a gate portion g for injecting a material is formed.

  On the other hand, the air vent groove 40 is formed on the end side portion 2A side of the cavity portion 36 ′ that forms the second extending portion 36 that is opposite to the first extending portion 35 in the longitudinal direction (arrow a direction). Is formed in communication with the cavity portion 36 '(see FIGS. 3 and 6).

  The setting specifications of the cavity portion 36 ′ will be described with reference to a partially enlarged view of the second extending portion 36 (cavity portion 36 ′) shown below in FIG.

  As shown in FIG. 3, the length of the second extending portion 36 (cavity portion 36 ') along the end side portion 2A is L, and the air vent groove 40 (because it is an extremely small area, it is hatched. When the width along the end side portion 2A is designated as Wa, the width Wa of the air vent groove 40 is L / 3 or less, and the center position that bisects the width Wa of the air vent groove 40 in the width direction P is configured to be set in an area δ located closer to the developer circulation notch 23 than L / 2 or L / 2.

  When the width Wa of the air vent groove 40 exceeds L / 3, no matter how the depth H (see FIG. 6) of the air vent groove 40 is adjusted, burrs are generated from the cavity portion in contact with the air vent groove 40. In other words, it is difficult to sufficiently fill the corner portion 36a on the end side portion 2A side of the second extending portion 36 with the material. That is, no matter how the depth H (see FIG. 6) of the air vent groove 40 is adjusted, burrs are generated or the edge shape of the corner portion 36a on the end side portion 2A side of the second extending portion 36 is formed. Tends to be inconvenient (so-called short circuit, rounded edges). A more preferable range of the width Wa of the air vent groove 40 is L / 20 to L / 6.

  Further, when the center position P that bisects the width Wa of the air vent groove 40 is out of the area δ located on the developer circulation notch 23 side than L / 2 or L / 2, Similarly to the above, no matter how the depth H (see FIG. 6) of the air vent groove 40 is adjusted, the end of the second extending portion 36 is generated without generating burrs from the cavity portion in contact with the air vent groove 40. It becomes difficult to sufficiently fill the corners 36a on the side 2A side. The width W of the air vent groove 40 is preferably formed so as to be within the area δ on the developer circulation notch 23 side than L / 2.

  The depth H of the air vent groove 40 can be set as appropriate so as to achieve the effects of the present invention, and is particularly preferably set within a range of H = 0.03 to 0.07 mm.

  The length L along the end side portion 2A of the second extending portion 36 (cavity portion 36 ') is 0.8 to 1.5 mm, preferably 0.9 to 1.1 mm. The lengths along the end side portion 2A of the first extending portion 35 (cavity portion 35 ') located on the opposite side are also equal. It is sufficient that the developer existing between the developing blade 10 and the developing roller is long enough to prevent the developer from leaking out of the developing region in the longitudinal direction of the developing blade 10 and should be longer than necessary. Is not desirable from the viewpoint of cost reduction.

  The structure of the developing blade manufacturing mold of the present invention will be further described. As shown in FIGS. 5 and 6, the mold is a lower mold for positioning and mounting the long support member 20. A mold 70 and an upper mold 80 attached to the long support member 20 placed on the lower mold 70 are provided. The upper mold 80 has a cavity Cv corresponding to the shape of the blade member 30 and a gate portion g (FIG. 5) and an air vent groove 40 (FIG. 6) for injecting material. As shown in FIG. 6, the outermost position 40 a of the air vent groove 40 communicates with a gap 75 generated when the lower mold 70 and the upper mold 80 are combined through the long support member 20. Are arranged and formed. Thereby, the air vent groove 40 can reliably communicate the inside of the cavity Cv and the outside atmosphere. Moreover, with the illustrated structure, the length of the air vent groove 40 (the length for communicating with the external atmosphere) can be made extremely short, for example, about 0.3 to 0.5 mm.

  In the mold structure according to the present invention, a mechanism for evacuating the periphery of the cavity Cv is not provided around the cavity Cv corresponding to the shape of the blade member 30.

  This is because if the vacuuming configuration is adopted, the structure itself becomes complicated, and extra processing and parts (for example, packing or the like) are required, which may be inconvenient.

  Further, although the cavity Cv is one piece due to the limitation of the size of the paper surface, it can be set to a large number of pieces so that a plurality of developing blades 10 can be molded simultaneously.

  Normally, a pin (not shown) for positioning the long support member 20 is formed on the upper part of the lower mold 70, and the hole 14 formed in the support member 20 is formed in the pin. Can be inserted and positioned and fixed.

<Developing blade manufacturing method>
The developing blade is manufactured using the developing blade manufacturing mold described above. A preferred embodiment of the manufacturing method is an injection molding method, and it is desirable that the material to be molded is a liquid silicone rubber.

  That is, the long support member 20 is positioned, fixed and placed on the lower mold 70, and the upper mold 80 is deposited on the upper mold 80. Rubber is injected, and liquid silicone rubber is filled into the cavity Cv corresponding to the shape of the blade member 30. A schematic flow in which the liquid silicone rubber is filled is indicated by arrows in FIG.

  That is, when viewed roughly, the liquid silicone rubber injected from the gate part g is substantially from the one end side where the gate part g exists to the substantially other end opposite to the gate part g where the air vent groove 40 exists. To the side, along the longitudinal direction. Finally, since the predetermined air vent groove 40 of the present application is formed in the second extending portion 36 filled with liquid silicone rubber, the air vent groove 40 and / or the second extending portion 36 (cavity The material can be sufficiently filled in the corner portion 36a on the end side portion 2A side of the second extending portion 36 (cavity portion 36 ') without generating burrs from the portion 36').

  Thereafter, the liquid silicone rubber is cured to such an extent that the liquid silicone rubber can maintain its shape, and then the lower mold 70 and the upper mold 80 are opened, and the developing blade 10 as a product is taken out. The viscosity of the injected liquid silicone rubber is 50 to 1000 P (poise), more preferably 100 to 500 P. This is because the effect of the mold structure of the present invention has been confirmed with a viscosity in this range.

  Note that transfer molding may be used instead of the injection molding method.

Hereinafter, the present invention will be described in more detail with reference to specific experimental examples.
A developing blade manufacturing die as shown in FIGS. 3 to 6 is prepared, and as shown in FIG. 3, from the substantially one end side where the gate portion g is present to the substantially other end side where the air vent groove 40 is present ( The developing blade 10 was manufactured by injecting liquid silicone rubber into the cavity Cv corresponding to the shape of the blade member 30 toward the opposite side of the gate portion g). The long support member 20 was SUS304 stainless steel (thickness: 1.0 mm). The length in the longitudinal direction of the support member 20 was 240 mm.

  As shown in Table 1 below, various forms of air vent grooves 40 are formed in the second extending portion 36, which is finally filled with the liquid silicone rubber, with various positions to be installed. Whether or not a so-called short-circuit defect occurs in the corner portion 36a on the end side portion 2A side of the portion 36 and whether or not burrs are generated in the cavity portion in contact with the air vent groove 40 were confirmed.

  That is, as shown in FIG. 7, the length L (here, L = 1 mm) along the end side portion 2A of the second extending portion 36 is divided into six equal lengths, and the second length as shown in FIG. The position of the outermost line Z1 of the extending part 36 is the A part, and in that order, the B part, the C part, the D part, the E part, the F part, and the G part that is the position of the innermost line Z2 did.

  And about the B part, the C part, the D part, the E part, and the F part, the air vent groove 40 of the following Table 1 is arranged so that the line passing through them becomes the center of the width Wa of the air vent groove 40 as illustrated. It set as follows. That is, for the B part, the C part, the D part, the E part, and the F part, the center position P that bisects the width Wa of the air vent groove in the width direction is the B part, the C part, the D part, the E part, and the F part. To match each line. In addition, the width Wa of the air vent groove of the A part and the B part on both sides is the distance from the lines Z1 and Z2 at the end parts (A-I, A-II, A-III and G- in FIG. 7). I, G-II, G-III). A-I, A-II, A-III; B-I, B-II, B-III; C-I, C-II, C-III; D-I, D-II, D-III; E- I, E-II, E-III; F-I, F-II, F-III; GI, G-II, G-III; J1, J2; K1, K2, K3, K4; The width Wa of the formed air vent groove 40 is shown. For example, A-I corresponds to the width Wa of the A-I-1, A-I-2, and A-I-3 samples in Table 1 below. The same relationship applies to other samples related to A to G.

  The results are shown in Table 1 below.

  From the results shown in Table 1, the following can be understood.

  That is, when the length along the end side portion 2A of the second extending portion 36 (cavity portion 36 ') is L and the width along the end side portion 2A of the air vent groove 40 is Wa, the air vent groove 40 has a width Wa equal to or less than L / 3, and the center position P that bisects the width Wa of the air vent groove 40 in the width direction is closer to the developer circulation notch than L / 2 or L / 2. For the sample set in the area δ, the depth H (see FIG. 6) of the air vent groove 40 is set to a predetermined depth so that no burrs occur and no short-circuit defect occurs. Thus, the developing blade 10 having the blade member 30 can be obtained.

  On the other hand, a sample in which the center position P that bisects the width Wa of the air vent groove 40 in the width direction does not exist in L / 2 or in the area δ located closer to the developer circulation notch than L / 2. Regarding (samples of A part, B part, and C part), no matter how the depth H (see FIG. 6) of the air vent groove 40 is adjusted, burrs are generated or the second extending part 36 This causes a so-called short circuit in which the edge shape of the corner portion 36a on the end side portion 2A side is not clear. The results shown in Table 1 above were confirmed to have the same tendency in the viscosity range of 50 to 1000 P (poise).

  Furthermore, as shown in FIG. 7, for J1 having a width Wa = L / 3 between E and G and J2 having a width Wa = L / 3 between D and F, by adjusting the depth H, It was confirmed that the occurrence of burrs can be avoided (of course, short circuit was avoided).

  Further, as shown in FIG. 7, K1 having a width Wa = L / 2 between D and G, K2 having a width Wa = L / 2 between C and F, and a width Wa = (2 between C and G. / 3) For K3 having L and K4 having a width Wa = (5/6) between B and G, the occurrence of burrs could not be avoided by adjusting the depth H.

  The present invention can be used for a technique related to a developing blade used in a developing device of an electrophotographic image forming apparatus.

DESCRIPTION OF SYMBOLS 10 ... Developing blade 14 ... Hole part 20 ... Support member 23 ... Notch part for a developer circulation 30 ... Blade member 30a ... Small piece part 33 ... Blade notch part 35 ... First extension part 35 '... Cavity part 36 ... First 2 Extension part 36a ... Corner part 36 '... Cavity part 40 ... Air vent groove 70 ... Lower mold 75 ... Gap 80 ... Upper mold g ... Gate part 2A ... End side part Cv ... Cavity

Claims (13)

On the long support member, a blade member is formed along the longitudinal direction of one end side portion of the support member, and the support member is in the vicinity of both end portions in the longitudinal direction of the end side portion. And the blade member is disposed at both ends in the longitudinal direction at both ends in the longitudinal direction of the end side portion beyond the developer circulation notch. A mold used in the manufacture of a developing blade having a first extension part and a second extension part extended to the vicinity of the part,
The mold includes a cavity corresponding to the shape of the blade member, and a gate portion for injecting a material is formed on a side where the first extending portion is formed. What is the first extending portion? An air vent groove is formed in communication with the end side portion side of the cavity portion forming the second extending portion at a position opposite to the longitudinal direction,
When the length along the end side portion of the second extending portion is L and the width along the end side portion of the air vent groove is Wa, the width Wa of the air vent groove is L / 3 or less. In addition, the center position P that bisects the width Wa of the air vent groove in the width direction is set in L / 2 or in the area δ located on the developer circulation notch portion side than L / 2. A mold for manufacturing a developing blade.   2. The developing blade manufacturing die according to claim 1, wherein a width Wa of the air vent groove is formed so as to be within an area δ closer to the developer circulation notch than L / 2. 3.   The mold for manufacturing a developing blade according to claim 1 or 2, wherein a width Wa of the air vent groove is L / 20 to L / 6.   The mold for manufacturing a developing blade according to any one of claims 1 to 3, wherein a depth H of the air vent groove is 0.03 to 0.07 mm.   The mold for manufacturing a developing blade according to any one of claims 1 to 4, wherein a length L along the end side portion of the second extending portion is 0.8 to 1.5 mm.   The mold includes a lower mold for positioning and placing a long support member, and an upper mold attached to the long support member placed on the lower mold. The upper die has a cavity corresponding to the shape of the blade member, and has a gate portion and an air vent groove for injecting a material. Mold for developing blade.   7. The outermost position of the air vent groove is disposed so as to communicate with a gap generated when a lower mold and an upper mold are combined through a long support member. The mold for manufacturing a developing blade according to any one of the above.   The mold for manufacturing a developing blade according to any one of claims 1 to 7, wherein a mechanism for evacuating the periphery of the cavity is not provided around the cavity corresponding to the shape of the blade member.   The mold for manufacturing a developing blade according to any one of claims 1 to 8, wherein the cavity is set in a multi-cavity so that a plurality of developing blades are simultaneously formed.   10. A method of manufacturing a developing blade by injecting a material into the developing blade manufacturing mold according to claim 1, wherein the material is a rubber material. Manufacturing method.   The method for producing a developing blade according to claim 10, wherein the rubber material is liquid silicone rubber.   The method for producing a developing blade according to claim 11, wherein the developing blade is formed by an injection molding method.   The method for producing a developing blade according to claim 12, wherein the injected liquid silicone rubber has a viscosity of 50 to 1000 P (poise).

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