JP2008233495A - Developing blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing blade designed so as not to disturb developer circulation in an electrophotographic image forming apparatus. <P>SOLUTION: The developing blade includes: a support member 12; and a blade member 15 disposed along one edge 12A of the support member 12 so as to cover the edge 12A except both ends of the edge 12A. Thus, the developing blade is free from an area where developer remains, and extra developer scraped from the developing roller by the developing blade is efficiently circulated and recovered into a hopper without staying on the developing blade. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a developing blade, and more particularly to 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. 13, a developing device 101 having a structure including a hopper 102, a developing roller 103, a rotatable stirring plate 104, and a developing blade 105 is known (see FIG. 13). Patent Document 1). In the developing device 101, the developer 106 in the hopper 102 is supplied to the developing roller 103 by the stirring plate 104, and the developer is thinly formed on the peripheral surface of the developing roller 103 by frictional charging between the developing blade 105 and the developing roller 103. And the excess developer is returned to the hopper 102. The developer 106 is transferred from the developing roller 103 to the photosensitive drum 107 on which the latent image is formed, and development is performed.

As a conventional developing blade 105, for example, as shown in FIG. 14, a rubber blade member 115 is provided along an end side portion 112A of a metal support member 112 having a thickness of about 0.1 mm. Things are known.
Conventionally, excess developer scraped off by the developing blade does not return to the hopper and stays in the vicinity of the developing roller and the developing blade, thereby causing deterioration of the developer and thinning of the developer on the developing roller. In order to prevent generation of streaks and unevenness in layers, it has been studied to provide a guide member or a magnet roll (Patent Documents 2 and 3).
JP 2003-43812 A JP 2004-93924 A JP-A-10-301396

However, in the conventional developing blade 105 as described above, the end side portion 112A of the support member 112 and the tip end portion 115A of the blade member 115 do not coincide with each other, and as shown in FIG. When the side portion 112A protrudes from the front end portion 115A of the blade member 115, a state occurs in which the developer accumulates at this step portion and does not circulate. When the developer stays in such a portion, there is a problem that the developer is deteriorated, the developer thin layer on the developing roller is streaked, and unevenness occurs. Therefore, a developing blade that can circulate the developer more reliably is desired.
The present invention has been made in view of such a situation, and an object thereof is to provide a developing blade that does not hinder the circulation of the developer in the electrophotographic image forming apparatus.

In order to achieve such an object, the present invention is provided with a support member and one end side portion of the support member so as to cover the end side portion except for both end portions thereof. And a blade member.
As another aspect of the present invention, the support member is configured to include a plurality of protruding support portions on the end side portion.
As another aspect of the present invention, the protruding support portion protrudes from a tip portion of the blade member, and a protruding length of the protruding support portion protruding from the tip portion of the blade member is 1 mm or less, and the protrusion Of the support portions, the protrusion support portions located at the end portions on both sides of the blade member have a width of 10 mm or less protruding from the tip end portion of the blade member, and of the protrusion support portions, The projecting support portions excluding the projecting support portions located at the end portions were configured such that the total width projecting from the tip portion of the blade member was 100 mm or less.
As another aspect of the present invention, the blade member is configured to have a developer circulation notch in the vicinity of both end portions.
As another aspect of the present invention, the blade member is arranged on both surfaces of the support member.

  According to the present invention, since the blade member is disposed so as to cover the end side portion of the support member, the developing blade has no portion where the developer stays, and is scraped off from the developing roller by the developing blade. The excess developer thus produced is efficiently circulated and collected in the hopper without staying on the developing blade. Further, when the support member includes a plurality of projecting support portions, the blade member disposed so as to cover the end side portion of the support member can be reliably supported to prevent deformation, and the developing blade The function as a more stable. Further, even if the protruding support portion protrudes from the tip end portion of the blade member, the protruding length and the protruding width are within a predetermined range, so the step portion between the protruding support portion and the blade member Residual of the developer in the is prevented. Further, when the blade member has a notch for circulating the developer, the developer is sent to the opposite surface of the developing blade (the surface opposite to the surface that is in contact with the developing roller) and further into the hopper. It is efficiently circulated and recovered.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view showing an embodiment of the developing blade of the present invention, FIG. 2 is a cross-sectional view of the developing blade shown in FIG. 1, and (A) is an enlarged cross-sectional view taken along line I-I, (B) is an enlarged sectional view taken along line II-II. As shown in FIG. 1 and FIG. 2, the developing blade 11 has a supporting member 12 and one end side 12 </ b> A in the longitudinal direction (the direction indicated by the arrow a in FIG. 1) on one side of the supporting member 12. And a blade member 15 formed along. The blade member 15 covers the end side portion 12A of the support member 12 except for both end portions thereof.
The material of the support member 12 constituting the developing blade 11 is not 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), PBT, or the like. Examples thereof include a resin substrate such as (polybutylene terephthalate). Further, the thickness of the support member 12 is preferably about 0.1 mm if it is stainless steel, for example.

Further, the support member 12 includes a plurality of holes 13 along the end side portion 12B facing the end side portion 12A. The hole 13 can be arbitrarily set for attachment, positioning, and the like, and is not limited to the illustrated example.
The material of the blade member 15 constituting the developing blade 11 is not limited, and examples thereof include silicone rubber, nitrile rubber, fluorine rubber, urethane rubber, epichlorohydrin rubber, and hydrogenated nitrile rubber. The blade member 15 in the illustrated example has a shape in which the contact area with the developing roller has a curved surface and the thickness gradually decreases from the front end portion 15A toward the rear end portion 15B. Further, the length S (see FIG. 2A) where the blade member 15 protrudes from the support member 12 can be set, for example, in the range of 0 to 1.5 mm, preferably in the range of 0 to 1 mm. If the length S at which the blade member 15 protrudes from the support member 12 exceeds 1.5 mm, the tip portion 15A of the blade member 15 is likely to be deformed, which may hinder the function of the developing blade.

In the illustrated example, skirt portions 16A and 16B are disposed at both ends of the rear end portion 15B of the blade member 15. One of the skirt portions 16A and 16B is a portion where the gate is located in the manufacturing by injection molding described later, and the other is a portion where excess molding material flowing in the cavity of the mold is accumulated.
In such a developing blade 11, since the blade member 15 is disposed so as to cover the end side portion 12A of the support member 12, the developing blade 11 has no portion where the developer stays, and the developing blade The excess developer scraped off from the developing roller 11 is efficiently circulated and collected in the hopper without the developing blade staying.

  FIG. 3 is a plan view showing another embodiment of the developing blade of the present invention, FIG. 4 is a cross-sectional view of the developing blade shown in FIG. 3, and (A) is an enlarged cross-sectional view taken along line II. (B) is an II-II line arrow expanded sectional view. As shown in FIGS. 3 and 4, the developing blade 21 has a supporting member 22 and one end side 22A in the longitudinal direction (the direction indicated by the arrow a in FIG. 3) on one side of the supporting member 22. And a blade member 25 formed along. The blade member 25 covers the end side portion 22A of the support member 22 except for both end portions thereof.

  The support member 22 constituting the developing blade 21 includes projecting support portions 24 at both end portions of the end side portion 22 </ b> A, and the projecting support portions 24 are located at both end portions of the blade member 25. Such a projecting support portion 24 is a member for supporting the blade member 25 to prevent deformation, and in the illustrated example, the tip end of the projecting support portion 24 projects from the tip end portion 25 </ b> A of the blade member 25. The length T (see FIG. 4 (A)) that the protruding support portion 24 protrudes from the tip portion 25A of the blade member 25 is 1 mm or less, and the width W1 (see FIG. 3) that protrudes from the tip portion 25A is 10 mm or less. It is preferable. If the length T and the width W1 at which the tip of the protruding support 24 protrudes exceed the above range, the developer tends to stay in the step portion between the protruding support 24 and the blade member 25, which is not preferable.

Such a support member 22 can be the same as the support member 12 of the developing blade 11 described above except that the protrusion support portion 24 is provided.
Further, the blade member 25 constituting the developing blade 21 can be the same as the blade member 15 of the developing blade 11 described above, including the length S (see FIG. 4B) protruding from the support member 22. .
Also in the developing blade 21, skirt portions 26A and 26B are disposed at both ends of the rear end portion 25B of the blade member 25.

  FIG. 5 is a plan view showing another embodiment of the developing blade of the present invention, FIG. 6 is a sectional view of the developing blade shown in FIG. 5, and (A) is an enlarged sectional view taken along line I-I. , (B) is an enlarged sectional view taken along line II-II, and (C) is an enlarged sectional view taken along line III-III. The developing blade 31 shown in FIG. 5 and FIG. 6 is formed along one end side portion 32A in the longitudinal direction (the direction indicated by the arrow a in FIG. 5) on one side of the supporting member 32 and the supporting member 32. The blade member 35 is provided. The blade member 35 covers the end side portion 32A of the support member 32 except for both end portions thereof.

  The support member 32 constituting the developing blade 31 includes projecting support portions 34a at both end portions of the end side portion 32A. The projecting support portions 34a are located at both end portions of the blade member 35, and The blade member 35 is provided with two protruding support members 34b at positions where the blade member 35 is divided into about three. These protruding support portions 34a and protruding support members 34b are members for supporting the blade member 35 to prevent deformation, and in the illustrated example, the tips thereof protrude from the tip portion 35A of the blade member 35. The length T (see FIG. 6A) at which the protruding support portion 34a protrudes from the tip portion 35A of the blade member 35 is 1 mm or less, and the width W1 (see FIG. 5) protruding from the tip portion 35A is 10 mm. The following is preferable. Further, the length T (see FIG. 6C) that the protruding support portion 34b protrudes from the tip portion 35A of the blade member 35 is 1 mm or less, and the width W2 (see FIG. 5) that protrudes from the tip portion 35A is 50 mm or less. It is preferable that If the length T and the widths W1 and W2 at which the tips of the projecting support portions 34a and 34b project exceed the above range, it is not preferable because the developer tends to stay in the step portion between the projecting support portions and the blade member 35. .

In the present invention, the number of protruding support members 34b arranged to divide the blade member 35 is not limited, and may be one, or three or more, for example, as shown in FIG. As shown in the figure, it may be provided with five protruding support members 34b. However, the total of the width W2 (see FIG. 7) from which the protruding support member 34b protrudes from the tip portion 35A is preferably 100 mm or less.
Such a support member 32 can be the same as the support member 12 of the developing blade 11 described above except that the protrusion support portions 34a and 34b are provided.
Further, the blade member 35 constituting the developing blade 31 may be the same as the blade member 15 of the developing blade 11 described above, including the length S (see FIG. 6B) protruding from the support member 32. .
In the developing blade 31, skirt portions 36 </ b> A and 36 </ b> B are disposed at both ends of the rear end portion 35 </ b> B of the blade member 35.

  When the support member has a plurality of protruding support portions like the developing blades 21 and 31, the blade member disposed so as to cover the end side portion of the support member is reliably supported and deformed. Can be prevented, and the function as a developing blade is further stabilized. Further, even if the protruding support portion protrudes from the tip end portion of the blade member, the developer is prevented from staying in the step portion between the protruding support portion and the blade member.

  FIG. 8 is a plan view showing another embodiment of the developing blade of the present invention, FIG. 9 is a cross-sectional view of the developing blade shown in FIG. 8, and (A) is an enlarged cross-sectional view taken along the line I-I. (B) is an II-II line arrow expanded sectional view. As shown in FIGS. 8 and 9, the developing blade 41 has a support member 42, one side of the support member 42, and one end side portion 42A in the longitudinal direction (the direction indicated by the arrow a in FIG. 8). And a blade member 45 formed along the edge. The blade member 45 covers the end side portion 42A of the support member 42 except for both ends thereof, and the developer circulation notch portion 47 is provided in the vicinity of the end portions 45a and 45a on both sides of the blade member 45. have. The developer circulation notch 47 of the blade member 45 removes excess developer existing between the developing blade 41 and the developing roller from the opposite surface of the developing blade 41 (the developing roller via the support member 42). To the opposite side) for efficient circulation recovery in the hopper. The size and shape of the developer circulation notch 47 can be appropriately set. For example, in the case of a rectangular notch, the width W ′ is 1 to 3 mm and the depth D is 0.5 to 0.5. It can be set within a range of 1.5 mm. Further, the length S (see FIG. 9B) from which the blade member 45 protrudes from the support member 42 is set in the range of 0 to 1.5 mm, preferably 0 to 1 mm, as in the above-described embodiment. Can do.

The support member 42 may be provided with a developer circulation notch so as to correspond to the developer circulation notch 47 so that the developer circulation notch 47 enters the support member 42. Good. In this case, the depth D of the developer circulation notch 47 can be set in the range of 0.5 to 3 mm, for example.
The supporting member 42 and the blade member 45 constituting the developing blade 41 are the same as the supporting member 12 and the blade member 15 of the developing blade 11 described above except that the developer circulating cutout portion 47 is provided. it can.
In the developing blade 41, skirt portions 46A and 46B are disposed at both ends of the rear end portion 45B of the blade member 45.

In such a developing blade 41, since the blade member has a notch for circulating the developer, the developer is fed to the opposite surface of the developing blade (the surface opposite to the surface in contact with the developing roller). And more efficiently circulated and recovered in the hopper.
The above-described embodiments are examples, and the present invention is not limited to these embodiments.
For example, the cross-sectional shape of the blade members 15, 25, 35, 45 is not limited to that of the above-described embodiment.

The developing blade of the present invention may be provided with blade members on both sides of the support member. FIG. 10 is a cross-sectional view corresponding to FIG. The developing blade 11 ′ shown in FIG. 10 includes blade members 15 formed along one end side portion 12 </ b> A in the longitudinal direction on both surfaces of the support member 12. Also in this case, the blade member 15 covers the end side portion 12A of the support member 12 except for both end portions thereof. Further, the developing blade having the blade members on both sides as described above may be provided with the above-described protruding support member, or may be provided with the developer circulation notch as described above.
The developing blade of the present invention can be manufactured by either injection molding or transfer molding.

Here, a manufacturing example by injection molding will be described with the developing blade 11 described above as an example.
FIGS. 11 and 12 are views for explaining an example of a mold used when the developing blade of the present invention is manufactured by injection molding. FIG. 11 is a view of FIG. 2A of the developing blade 11 described above. FIG. 12 is a cross-sectional view corresponding to the portion shown in FIG. 2B of the developing blade 11 described above.

  11 and 12, a mold 51 to be used includes an upper mold 52 and a lower mold 53 having a flat mold surface. The upper mold 52 includes a mold surface provided with a cavity 55 for forming the blade member 15, and a gate 57 communicating with the cavity 55. The gate 57 is disposed at a portion corresponding to the skirt portion 16A of the developing blade 11 described above. Then, the upper mold 42 and the lower mold 43 are mold-matched and clamped so as to sandwich the support member 12. Then, the developing blade 11 is manufactured by injecting a molding material from the gate 57 to fill the cavity 55.

  It can be used for a developing blade used in a developing device of an electrophotographic image forming apparatus.

It is a top view which shows one Embodiment of the image development blade of this invention. 2A and 2B are cross-sectional views of the developing blade shown in FIG. 1, in which FIG. 1A is an enlarged cross-sectional view taken along line II and FIG. 1B is an enlarged cross-sectional view taken along line II-II. It is a top view which shows other embodiment of the image development blade of this invention. 4A and 4B are cross-sectional views of the developing blade shown in FIG. 3, in which FIG. It is a top view which shows other embodiment of the image development blade of this invention. FIG. 6 is a cross-sectional view of the developing blade shown in FIG. 5, (A) is an enlarged cross-sectional view taken along line II, (B) is an enlarged cross-sectional view taken along line II-II, and (C) is an III-III line arrow. FIG. It is a top view which shows other embodiment of the image development blade of this invention. It is a top view which shows other embodiment of the image development blade of this invention. It is sectional drawing of the image development blade shown by FIG. 8, (A) is an II-II arrow expanded sectional view, (B) is an II-II arrow expanded sectional view. FIG. 5 is a cross-sectional view corresponding to FIG. 2 showing another embodiment of the developing blade of the present invention. It is a figure for demonstrating the metal mold | die used for manufacture of the image development blade of this invention. It is a figure for demonstrating the metal mold | die used for manufacture of the image development blade of this invention. It is a figure which shows an example of the structure of the conventional image development apparatus. It is a perspective view which shows an example of the conventional developing blade.

Explanation of symbols

11, 21, 31, 41, 11 '... developing blade 12, 21, 32, 42 ... support member 12A, 22A, 32A, 42A ... end side portion 15, 25, 35, 45 ... blade member 24, 34a, 34b ... Protruding support 47 ... Notch for developer circulation

Claims (5)

  A developing blade, comprising: a support member; and a blade member disposed along one end side portion of the support member so as to cover the end side portion except for both end portions thereof.   The developing blade according to claim 1, wherein the support member includes a plurality of projecting support portions on the end side portion.   The protruding support portion protrudes from the tip end portion of the blade member, and the protruding length of the protruding support portion protruding from the tip end portion of the blade member is 1 mm or less. Of the protruding support portions, the blade member The protruding support portions positioned at the ends on both sides of the blade have a width protruding from the tip end portion of the blade member of 10 mm or less, and of the protruding support portions, the protruding support portions positioned at the ends on both sides of the blade member 3. The developing blade according to claim 2, wherein the projecting support portion excluding the width of the projecting support portion projects from the tip of the blade member is 100 mm or less.   The developing blade according to claim 1, wherein the blade member has a developer circulation notch in the vicinity of both end portions.   The developing blade according to claim 1, wherein the blade member is disposed on both surfaces of the support member.

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