JP2018180467A - Developing sleeve and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a developing roller to selectively nap developer and favorably convey developer.SOLUTION: A developing sleeve comprises: a sleeve substrate for a developing sleeve; and a developer holding layer that is provided on the sleeve substrate, where the developer holding layer has a concavo-convex part that holds developer along a surface direction of the sleeve substrate, and has non-magnetic layers 5 formed on concave parts of the concavo-convex part. The non-magnetic layers may cover at least the concave parts. An image forming apparatus may include the developing sleeve.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a developing sleeve (developing roller) used in, for example, a copying machine, a facsimile, a printer, etc. More specifically, the developer carried on the developing sleeve is opposed to the photosensitive drum with the developing sleeve with a gap. The present invention relates to a developing sleeve which is conveyed to a developing area and develops an electrostatic latent image on the photosensitive drum to form a toner image.

  In an image forming apparatus such as a copying machine using an electrophotographic method, a developer is attached to an electrostatic latent image formed on an image carrier such as a photosensitive drum to make a visible image. Among such image forming apparatuses, one using a two-component developer composed of toner and magnetic carrier is known.

  In such an image forming apparatus, while a two-component developer is magnetically held on a rotating developing sleeve, the two-component developer is conveyed to the vicinity of the image carrier, and the electrostatic latent image of the photosensitive member is developed with the toner in the developer. Visualize.

  In the method of visualizing in this manner, the developer is held by the magnetic force on the developing sleeve by providing the magnet fixedly disposed inside the rotating developing sleeve, and the developer is regulated to the developing sleeve. The blades are arranged to face each other at a predetermined interval. By so doing, the two-component developer is conveyed to the vicinity of the photosensitive member on the developing sleeve while regulating the developer amount to a desired amount.

  At this time, in order to stably transport the developer, conventionally, a developing sleeve having concavities and convexities formed by sandblasting with abrasive grains and a plurality of grooves extending parallel to the rotational axis of the developing sleeve are formed on the surface. I use a sleeve.

JP 2014-235343 A

  In the developing sleeve described in Patent Document 1 described above, it is shown that a large number of concave shapes are formed on the outer surface by laser processing.

  The developing sleeve is made of nonmagnetic material of any of aluminum alloy, brass, stainless steel, and conductive resin, but is often made of aluminum alloy in order to reduce cost and improve processing accuracy. . When processing a concave shape to the outer surface by laser processing, while processing time is required, there is a concern that the precision of processing shape may fall.

  SUMMARY OF THE INVENTION The present invention provides a developing sleeve and an image forming apparatus capable of making a developer stand out in a predetermined pattern.

  The present invention comprises a developing sleeve base and a developer holding layer provided on the surface of the developing sleeve base and made of a magnetic material, and holding the developer on the surface of the developer holding layer. The present invention is characterized in that a developing sleeve is provided in a predetermined pattern shape for forming a developing sleeve in which a nonmagnetic portion is provided at least in a recess of the above-mentioned uneven portions.

  According to the present invention, it is possible to realize a developing sleeve and an image forming apparatus capable of causing the developer to be favorably raised in a predetermined pattern.

FIG. 1 is a cross-sectional view of a developing sleeve according to an embodiment of the present invention. FIG. 2 is a top view of a dot pattern of a developing sleeve according to the present invention. FIG. 2 is a configuration diagram of a developing sleeve and a photosensitive drum according to the present invention.

Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 3.
FIG. 1 is a cross-sectional view of a developing sleeve 7 according to an embodiment of the present invention. FIG. 2 is a top view of the dot pattern of the developing sleeve 7 shown in FIG. FIG. 3 is a block diagram of the developing sleeve 7 and the photosensitive drum 4 according to the present invention.

  As shown in FIG. 3, the developing roller 1 includes a core metal 2, a cylindrical magnet 3, and the above-described cylindrical developing sleeve 7. The metal core 2 is disposed such that its longitudinal direction is parallel to the longitudinal direction of the photosensitive drum 4 and is fixed to the image forming apparatus without rotating.

  The magnet body 3 is made of a magnetic material and formed in a cylindrical shape, and a plurality of fixed magnetic poles are attached. The magnet 3 is fixed to the outer periphery of the core metal 2 without rotating around the axis.

  The fixed magnet is a long and rod-like magnet, and is attached to the magnet 3. The fixed magnet extends in the longitudinal direction of the developing roller 1 which is the magnet 3 and is provided over the entire length of the magnet 3. The magnet 3 having the above-described configuration is contained in the developing sleeve 7.

  Here, one fixed magnetic pole is opposed to the storage tank in which the developer is stored. This one fixed magnetic pole forms a pumping magnetic pole, and a magnetic force is generated on the outer surface of the developing sleeve 7, that is, the developing roller 1 to attract the developer in the storage tank to the outer surface of the developing sleeve 7.

  Another fixed magnetic pole faces the photosensitive drum on which an electrostatic latent image is formed. The fixed magnetic pole forms a developing magnetic pole, and generates a magnetic force on the outer surface of the developing sleeve 7, that is, the developing roller 1 to form a magnetic field between the developing sleeve 7 and the photosensitive drum 4.

  The fixed magnetic pole forms a magnetic brush by the magnetic field to deliver the toner of the developer adsorbed on the outer surface of the developing sleeve 7 to the photosensitive drum 4.

  At least one fixed magnetic pole is provided between the aforementioned scooping magnetic pole and the developing magnetic pole. The at least one fixed magnetic pole generates a magnetic force on the outer surface of the developing sleeve 7, that is, the developing roller 1 to convey the developer before development toward the photosensitive drum 4 and sensitize the developed developer. The body drum 4 is transported into the storage tank.

  When the developer is adsorbed to the outer surface of the developing sleeve 7, the fixed magnetic pole mentioned above is provided on the outer surface of the developing sleeve 7 in such a manner that a plurality of magnetic carriers of the developer overlap along the magnetic lines of force generated by the fixed magnetic pole. (Settle)

  In this manner, the magnetic carrier "ears" on the outer surface of the developing sleeve 7 in a state where the plurality of magnetic carriers overlap along the magnetic lines of force and stand on the outer surface of the developing sleeve 7. Then, the toner described above is adsorbed to the spiked magnetic carrier. That is, the developing sleeve 7 has a function of holding (adsorbing) the developer on the outer surface by the magnetic force of the magnet 3. That is, the outermost layer of the developing sleeve 7 is a developer holding layer.

  The developing sleeve 7 is an endless cylindrical member, and is formed in a cylindrical shape in the present embodiment. The developing sleeve 7 includes (accommodates) the magnet body 3 and is rotatably provided around the axial center. The developing sleeve 7 is rotated so that the inner circumferential surface thereof sequentially faces the fixed magnetic pole. The base material of the developing sleeve 7 is made of, for example, a nonmagnetic material such as aluminum alloy, brass, stainless steel (SUS), or conductive resin.

  Here, as a substrate (developing sleeve substrate) of the developing sleeve 7, stainless steel and aluminum alloy are particularly preferable. Stainless steel and aluminum alloys are excellent in workability and lightness. When using an aluminum alloy, it is preferable to use A6063, A5056 and A3003. When using SUS, it is preferable to use SUS303, SUS304, and SUS316. In the illustrated example, the developing sleeve 7 is made of SUS316.

  The outer diameter of the developing sleeve 7 is, for example, 20 mm in the present embodiment, and the length in the axial (axial center) direction of the developing sleeve 7 is 400 mm.

  Next, the process of forming a concave shape on the outer surface of the developing sleeve 7 using photolithography will be described below.

Example 1
First, a metal material is electroformed on the outer surface of the base of the developing sleeve 7 to form an underlayer (plating layer) 6 made of a magnetic material. In the present embodiment, the thickness (plated film thickness) of the underlayer 6 is 20 μm. The plating material is preferably soft magnetism having high permeability and small residual magnetization. In the case of a Ni-based metal material, pure nickel-nickel-phosphorus alloy / nickel-iron alloy may, for example, be mentioned. The coercive force Ho is preferably about 0.1 [Oe] to 20 [Oe].

  Next, the nonmagnetic portion 5 is formed by applying a nonmagnetic material to the surface of the underlayer 6 of the developing sleeve 7 and patterning it into a predetermined shape. Here, in the present embodiment, a resist material is used as a material for forming the nonmagnetic portion 5, and a liquid resist, a dry film resist, an electrodeposition resist and the like can be mentioned as to the method of forming the material.

  In addition, in the formation of the nonmagnetic portion 5, depending on the case, a conductive filler may be mixed to give conductivity. In this example, a permanent dry film resist [negative] having a film thickness of 60 μm was used. In addition, for example, a coating of a coupling agent, formation of a metal oxide film, or the like may be employed as the base treatment to improve the adhesion between the substrate and the resist.

  Next, a photomask (not shown) is disposed on the surface of the coating film of nonmagnetic material, and exposure and development processing is performed to form a predetermined opening shape. There are several methods for exposure. For example, there is a method in which a coating film of nonmagnetic material is exposed on a plane and then wound around the developing sleeve 7. As another method, there is also a method in which a flexible resin photomask is wound around the developing sleeve 7 and exposure is performed while rotating the developing sleeve 7 or the light source.

  As another method, a method of drawing a pattern directly on the outer surface of the developing sleeve 7 using a condensed laser beam or the like can also be applied. A method in which a pattern is directly drawn on the roll surface with a condensing laser or the like is preferable because a fine pattern can be formed and a seam of the fine pattern does not occur.

  Next, development can be processed by a method such as dipping or spraying, and the method is not limited to this.

  After development, electroforming plating is performed on the opening in which the pattern is formed in the nonmagnetic portion 5, and the convex portion 6 a is formed on the underlayer 6. That is, on the base material surface of the developing sleeve, the uneven developer holding layer 100 in which the nonmagnetic portion 5 is embedded in the concave portion is formed. Here, it is preferable that the plating material forming the convex portion 6a be soft magnetic, which has high permeability and small residual magnetization. In the case of a Ni-based metal material, pure nickel-nickel-phosphorus alloy / nickel-iron alloy may, for example, be mentioned. The coercive force Ho is preferably about 0.1 [Oe] to 20 [Oe]. The thickness of the plating film may be equal to or less than the thickness of the nonmagnetic portion 5. In the present embodiment, the half thickness of the nonmagnetic portion 5 is 30 μm.

  After the electroforming plating, the configuration shown in FIG. 1A and FIG. 2 is obtained, and a fine circular concave shape pattern regularly formed on the outer surface of the developing sleeve 7 is formed. In the present embodiment, the micro-concave patterns are arranged in a lattice shape, and the interval is 130 μm, the diameter is 70 μm, and the height is 30 μm. The concave shape pattern is not limited to dots, and may be polygonal or line shape.

  Finally, post-baking and UV irradiation are performed to permanently cure the nonmagnetic portion 5.

  Next, using the developing sleeve 7 of the present invention, an embodiment in which the developer ears on the outer surface along magnetic lines of force will be described.

  In the configuration of FIG. 1 (A), the developer concentrates magnetic lines of force on the convex shaped portion of the metal material 6 and causes a spike. In order to make the developer spike at a high density more selectively, the nonmagnetic portion 5 is provided at least in the concave portion of the concavo-convex portion so that the developer does not brush at the concave shape portion in the developer holding layer 100 However, the nonmagnetic layer having good smoothness may be formed on the entire surface of the uneven portion. For example, in order to prevent the developer from remaining due to residual magnetization when removing the developer, it is preferable to form a nonmagnetic layer with a thickness of 20 μm or more on the surface of the uneven portion.

  As another advantage, the convex portion 6 a (convex shape portion) formed of a metal material is configured to be surrounded by the nonmagnetic portion 5, so the developer is assisted in its transportability in the concave portion, and as a result Transportability is improved. Further, since the convex portion 6 a is protected by the nonmagnetic portion 5, the temporal metal wear occurring with the developer is reduced.

Example 2
First, a metal material is electroformed and plated on the outer surface of the developing sleeve 7 to form the underlayer 6. In the present embodiment, the thickness (plated film thickness) of the underlayer 6 is 20 μm. The plating material is preferably soft magnetism having high permeability and small residual magnetization. In the case of a Ni-based metal material, pure nickel-nickel-phosphorus alloy / nickel-iron alloy may, for example, be mentioned. The coercive force Ho is preferably about 0.1 [Oe] to 20 [Oe].

  Next, a coating film of nonmagnetic material is applied to the outer surface of the developing sleeve 7 to a predetermined thickness. In the present embodiment, a resist is used as the nonmagnetic material, and a method of forming the resist includes a liquid resist, a dry film resist, an electrodeposition resist, and the like, and the present invention is not limited thereto. In some cases, conductive fillers may be mixed to provide conductivity. In this example, a permanent dry film resist [negative] having a film thickness of 60 μm was used. In addition, for example, a coating of a coupling agent, formation of a metal oxide film, or the like may be employed as the base treatment to improve the adhesion between the substrate and the resist.

  Next, a photomask (not shown) is disposed on the surface of the coating film of nonmagnetic material, and exposure and development processing is performed to form a predetermined opening shape. There are several methods for exposure. For example, there is a method in which a coating film of nonmagnetic material is exposed on a plane and then wound around the developing sleeve 7. As another method, there is also a method in which a flexible resin photomask is wound around the developing sleeve 7 and exposure is performed while rotating the developing sleeve 7 or the light source.

  As another method, a method of drawing a pattern directly on the outer surface of the developing sleeve 7 using a condensed laser beam or the like can also be applied. A method in which a pattern is directly drawn on the roll surface with a condensing laser or the like is preferable because a fine pattern can be formed and a seam of the fine pattern does not occur.

  Next, development can be processed by a method such as dipping or spraying, and the method is not limited to this.

  After development, electroforming plating is performed on the opening in which the pattern is formed in the nonmagnetic portion 5, and the convex portion 6 a is formed on the underlayer 6. That is, on the base material surface of the developing sleeve, the uneven developer holding layer 100 in which the nonmagnetic portion 5 is embedded in the concave portion is formed. The thickness (plating film thickness) of the convex portion 6 a of the developer holding layer 100 is equal to or larger than the thickness of the nonmagnetic portion 5, and in the present embodiment, the nonmagnetic portion 5 is 70 μm. The plating material is preferably soft magnetism having high permeability and small residual magnetization. In the case of a Ni-based metal material, pure nickel-nickel-phosphorus alloy / nickel-iron alloy may, for example, be mentioned. The coercive force Ho is preferably about 0.1 [Oe] to 20 [Oe].

  After electroforming plating, the configuration shown in FIG. 1B and FIG. 2 is obtained, and a fine circular concave shape pattern regularly formed on the outer surface of the developing sleeve 7 is formed. In the present embodiment, the micro-concave patterns are arranged in a lattice shape, and the interval is 130 μm, the diameter is 70 μm, and the height is 70 μm. The concave shape pattern is not limited to dots, and may be polygonal or line shape.

  Finally, post-baking and UV irradiation are performed to permanently cure the nonmagnetic layer 5.

  Next, using the developing sleeve 7 of the present invention, an embodiment in which the developer ears on the outer surface along magnetic lines of force will be described.

  In the configuration shown in FIG. 1B, the developer concentrates magnetic lines of force in the convex shape portion of the convex portion 6a made of a metal material. In order to cause the developer to spike at a high density more selectively, it is preferable to form a smooth nonmagnetic layer so that the developer does not brush at the concave shape portion around the convex portion 6a. It is preferable to form a nonmagnetic layer with a film thickness of 20 μm or more on the surface of the concavo-convex portion in order to prevent the residual magnetization due to the residual magnetization of the developer when removing the developer.

  However, in the structural example of FIG. 1 (B), compared with FIG. 1 (A), the protection of the side surface of the convex portion 6a made of a metal material is not sufficient. It is preferable to take measures against metal wear with time with the agent.

[Example 3]
First, a metal material is electroformed and plated on the outer surface of the base of the developing sleeve 7 to form the base layer 6. In the present embodiment, the thickness (plated film thickness) of the underlayer 6 is 20 μm. The plating material is preferably soft magnetism having high permeability and small residual magnetization. In the case of a Ni-based metal material, pure nickel-nickel-phosphorus alloy / nickel-iron alloy may, for example, be mentioned. The coercive force Ho is preferably about 0.1 [Oe] to 20 [Oe].

  Next, a coating film of a nonmagnetic material is applied to a predetermined thickness on the outer surface (the surface of the base layer 6) of the base of the developing sleeve 7. In the present embodiment, a resist is used as the nonmagnetic material, and a liquid resist, a dry film resist, an electrodeposition resist and the like can be mentioned as to the method of forming the resist. In some cases, conductive fillers may be mixed to provide conductivity. In this example, a permanent dry film resist [negative] having a film thickness of 60 μm was used. In addition, for example, a coating of a coupling agent, formation of a metal oxide film, or the like may be employed as the base treatment to improve the adhesion between the substrate and the resist.

  Next, a photomask (not shown) is disposed on the surface of the coating film of nonmagnetic material, and exposure and development processing is performed to form a predetermined opening shape around the nonmagnetic portion 5. There are several methods for exposure. For example, there is a method in which a coating film of nonmagnetic material is exposed on a plane and then wound around the developing sleeve 7. As another method, there is also a method in which a flexible resin photomask is wound around the developing sleeve 7 and exposure is performed while rotating the developing sleeve 7 or the light source.

  As another method, a method of drawing a pattern directly on the outer surface of the developing sleeve 7 using a condensed laser beam or the like can also be applied. A method in which a pattern is directly drawn on the roll surface with a condensing laser or the like is preferable because a fine pattern can be formed and a seam of the fine pattern does not occur.

  Next, development can be processed by a method such as dipping or spraying, and the method is not limited to this.

  After development, electroforming plating is performed on the opening where the pattern is formed around the nonmagnetic portion 5 to form the convex portion 6 a on the underlayer 6. The thickness (plating film thickness) of the convex portion 6a may be equal to or less than the thickness of the nonmagnetic portion 5, and the nonmagnetic portion 5 is 60 μm in this embodiment. The plating material is preferably soft magnetism having high permeability and small residual magnetization. In the case of a Ni-based metal material, pure nickel-nickel-phosphorus alloy / nickel-iron alloy may, for example, be mentioned. The coercive force Ho is preferably about 0.1 [Oe] to 20 [Oe].

  After electroforming plating, the configuration shown in FIG. 1C and FIG. 2 is obtained, and a fine circular concave shape pattern regularly formed on the outer surface of the developing sleeve 7 is formed. In the present embodiment, the micro-concave patterns are arranged in a lattice shape, and the distance is 130 μm, the diameter is 70 μm, and the height is 60 μm. The concave shape pattern is not limited to dots, and may be polygonal or line shape.

  Next, the nonmagnetic portion is peeled off once, and the nonmagnetic material is applied to the entire surface of the uneven portion again to form the nonmagnetic layer 5. Finally, post-baking and UV irradiation are performed to permanently cure the nonmagnetic layer 5. Thereby, the uneven developer holding layer 100 covered with the nonmagnetic layer 5 is formed on the surface of the base of the developing sleeve.

  Next, using the developing sleeve 7 of the present invention, an embodiment in which the developer ears on the outer surface along magnetic lines of force will be described.

  In the configuration shown in FIG. 1C, the developer concentrates magnetic lines of force on the convex shaped portion of the convex portion 6a and causes a spike. In order to cause the developer to spike at a high density more selectively, a smooth nonmagnetic layer may be formed on the surface of the uneven portion so that the developer does not spike at the concave shape portion of the developer holding layer. preferable. When the developer is removed, it is preferable to form a nonmagnetic layer with a thickness of 20 μm or more on the surface of the uneven portion in order to prevent the residual magnetization of the developer from remaining.

  However, there is a drawback that the number of processes increases as compared with FIG. Also, the film thickness of the nonmagnetic layer may be changed between the convex shape portion and the concave shape portion of the developer holding layer.

  According to the above-described developing sleeve, the developer can be selectively spiked, and the developer can be favorably transported. Therefore, high image quality of the image can be expected.

1: Developing roller 2: Core metal 3: Magnet 4: Photosensitive drum 5: Nonmagnetic layer 6: Metal material 7: Development sleeve

Claims (5)

A developing sleeve substrate,
A developer holding layer provided on the surface of the developing sleeve substrate and made of a magnetic material;
Irregularities for holding the developer are provided in a predetermined pattern on the surface of the developer holding layer,
A developing sleeve characterized in that a nonmagnetic portion is provided at least in the concave portion of the concavo-convex portion. The developer holding layer is composed of an underlayer provided on the surface of the developing sleeve substrate, and a plurality of convex portions formed on the underlayer.
The developing sleeve according to claim 1, wherein the nonmagnetic portion is provided on the underlayer so as to surround the plurality of convex portions.   The developing sleeve according to claim 1, wherein the developing sleeve base is formed of a nonmagnetic material.   The developing sleeve according to claim 1, wherein the nonmagnetic portion is provided in a layered manner on the surface of the uneven portion. An image forming apparatus comprising the developing sleeve according to any one of claims 1 to 4.

Images