JP2010156923A - Developing roller and development apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing roller and a development apparatus for suppressing image formation inferiority. <P>SOLUTION: The developing roller 53 is formed with a plurality of recesses 533 on a peripheral face and has a conductive paint film 532 covering the peripheral face including the recesses 533. The conductive paint film 532 is a layer dispersed with a conductive material 532b in an insulation material 532a and has a configuration where a content of a conductive material 532b at a position for forming the recess 533 is larger than the content of the conductive material 532b at the other positions. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developing roller and a developing device.

  Image forming apparatuses such as copiers and printers that employ an electrophotographic system transfer toner images onto a recording medium such as paper through a series of image forming processes such as a charging process, an exposure process, a development process, and a transfer process. Form. In the developing step, the toner image based on the electrostatic latent image is developed by supplying toner to an image carrier that carries the electrostatic latent image.

  As a developing device that supplies toner to an image carrier, a developing device described in Patent Document 1 is known. In order to supply a sufficient amount of toner to the image carrier, the developing device includes a developing roller having a plurality of concave portions formed on the peripheral surface and a large surface area, and a bias voltage is applied to the developing roller by applying a bias voltage thereto. The configuration is such that toner is electrically adsorbed to the peripheral surface and conveyed.

JP 2008-116543 A

  However, in the developing roller having the concave portion, the toner gradually accumulates and clogs in the concave portion with driving, and the toner in the concave portion may not contribute to the development and may remain on the developing roller side. Since the developing roller in this state cannot supply a sufficient amount of toner to the image carrier, image formation defects such as unevenness in the density of the toner image may be caused.

  The present invention has been made in view of the above problems, and an object thereof is to provide a developing roller and a developing device capable of suppressing image formation defects.

In order to solve the above problems, the present invention is a developing roller having a plurality of recesses formed on the peripheral surface, and has a coating layer that covers the peripheral surface including the recesses. It is a layer in which a conductive material is dispersed in an insulating material, and a configuration is adopted in which the content of the conductive material at a position where the concave portion is formed is larger than the content at other positions.
By adopting such a configuration, in the present invention, the content of the conductive material in the concave portion is increased, and the conductivity at the position where the concave portion is formed is increased, so that the toner is detached by the electrical action at the position. It is possible to improve ease of handling.

Moreover, in this invention, the structure that the said coating layer is formed by apply | coating the coating material in which the electrically conductive material is disperse | distributing in the insulating material to the surrounding surface containing the said recessed part is employ | adopted.
By adopting such a configuration, in the present invention, when the paint is applied to the peripheral surface including the recess, for example, a conductive material having a specific gravity greater than that of the insulating material flows into the recess due to its own weight. It becomes possible to easily manufacture a coating layer having a larger content of the conductive material in the other positions.

In the present invention, the coating layer employs a configuration in which the thickness at the position where the concave portion is formed is larger than the thickness at other positions.
By adopting such a configuration, in the present invention, by increasing the thickness of the coating layer in the concave portion, it is possible to increase the amount of the conductive material at the position where the concave portion is formed to further increase the conductivity. It becomes.

  Further, the present invention is a developing device having a developing roller to which a bias voltage superimposed with an alternating voltage is applied and which supplies toner contained therein to an image carrier for carrying an electrostatic latent image. In addition, a configuration in which the developing roller described above is provided as the developing roller is employed.

1 is a schematic configuration diagram illustrating a printer according to an embodiment of the present invention. It is a block diagram which shows the developing device in embodiment of this invention. It is a top view which shows the developing roller in embodiment of this invention. It is an enlarged view which shows the surrounding surface of the developing roller in embodiment of this invention. FIG. 5 is a sectional view taken along line XX in FIG. 4. It is a lineblock diagram showing the conductive paint application device in an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a laser beam printer (hereinafter referred to as a printer) is exemplified as an image forming apparatus including the developing device according to the present invention.

FIG. 1 is a schematic configuration diagram illustrating a printer 1 according to an embodiment of the present invention.
As shown in FIG. 1, the printer 1 has a photoconductor (image carrier) 2. Around the photoconductor 2, a charging device 3, an exposure device 4, a developing unit 5, and a primary unit are provided. A transfer device 6 is arranged.

  The photoconductor 2 has a cylindrical conductive substrate and a photosensitive layer formed on the peripheral surface (outer peripheral surface) thereof. In this embodiment, the photoconductor 2 can rotate in the direction of the arrow in FIG. 1 (clockwise). It has become a structure. The charging device 3 uniformly charges the peripheral surface of the photoreceptor 2 by corona charging or the like. The exposure device 4 receives image data from a host computer (not shown) and, based on the image data, exposes the circumferential surface of the uniformly charged photoconductor 2 with a predetermined pattern, thereby exposing the periphery of the photoconductor. An electrostatic latent image is formed on the surface.

  The developing unit 5 develops a toner image based on the electrostatic latent image by supplying toner to the photoreceptor 2. The developing unit 5 includes a developing device 50 (50B, 50M, 50C, 50Y) that stores therein black, magenta, cyan, and yellow toners. Each developing device 50 is configured to selectively face the photoconductor 2 by rotation around the rotation axis 5 a of the developing unit 5.

  The primary transfer device 6 is disposed opposite to the photosensitive member 2 with the intermediate transfer member 7 interposed therebetween, and primarily transfers a toner image carried on the photosensitive member 2 to the intermediate transfer member 7. The intermediate transfer member 7 is composed of an endless belt, and is configured to run at a speed substantially equal to the peripheral speed of the photosensitive member 2 in the direction of the arrow in FIG. The toner image primarily transferred to the intermediate transfer body 7 is secondarily transferred to the recording paper P conveyed from the paper feed cassette 9 by the secondary transfer device 8 at the conveyance destination, and is pressed and heated by the fixing device 10 for recording. It is fixed on the paper P.

Next, the configuration of the developing device 50 according to the present invention will be described in detail with reference to FIGS.
FIG. 2 is a configuration diagram illustrating the developing device 50 according to the embodiment of the present invention.
FIG. 3 is a plan view showing the developing roller 53 in the embodiment of the present invention.
FIG. 4 is an enlarged view showing the peripheral surface of the developing roller 53 in the embodiment of the present invention.
5 is a cross-sectional view taken along line XX in FIG.
Since the developing devices 50B, 50M, 50C, and 50Y have substantially the same configuration, one of them will be described as a representative.
As illustrated in FIG. 2, the developing device 50 includes a housing 51, a toner supply roller 52, a developing roller 53, and a regulating blade 54.

The housing 51 has a storage chamber 510 for storing the toner T therein. The photosensitive member 2 side of the bottom of the storage chamber 510 is opened, and the toner supply roller 52 and the developing roller 53 are disposed on the bottom. The toner supply roller 52 supplies toner T to the peripheral surface of the developing roller 53, and is configured to rotate in the arrow direction (clockwise) in FIG. The housing 51 is provided with a seal member 511 for preventing leakage of the toner T from the gap between the housing 51 and the developing roller 53 in the opening.
The regulating blade 54 regulates the layer thickness of the toner T held by the developing roller 53 to a constant level, and applies a charge to the toner T by frictional charging at the time of regulation. This regulating blade 54 also functions as a seal member for preventing leakage of the toner T on the upstream side in the rotation direction of the developing roller 53.

  The developing roller 53 supplies the toner T to the peripheral surface of the photoreceptor 2 by rotating in the direction of the arrow in FIG. 2 (counterclockwise) while carrying the toner T received from the toner supply roller 52 on the peripheral surface. To do. The developing roller 53 is a conductive roller, and is applied with a superimposed voltage obtained by superimposing an AC voltage on a DC voltage from a bias power source (not shown), and carries a toner T charged by the electrical action to carry a photosensitive member. In this configuration, the toner T is delivered to and from 2. As illustrated in FIG. 3, the developing roller 53 includes a columnar base material 531 and a conductive coating film (covering layer) 532 that covers the base material 531. In FIG. 3, the conductive coating film 532 is indicated by a two-dot chain line in order to improve the visibility of the concave portion 533 formed in the base material 531.

  The base material 531 is formed from, for example, a metal material such as aluminum or stainless steel. A plurality of concave portions 533 are formed on the peripheral surface of the base material 531 by rolling, for example. The concave portion 533 of the present embodiment includes a spiral first concave portion 533a and a second concave portion 533b that extend in the axial direction of the developing roller 53 and intersect each other. The inclination angle of the first recess 533a and the inclination angle of the second recess 533b with respect to the circumferential direction are approximately 45 degrees with opposite signs. As shown in FIG. 4, the recesses 533 formed in this manner are regularly arranged on the peripheral surface of the base material 531 to form a substantially lattice-like pattern. In the following description, the peripheral surface surrounded on all sides by the concave portion 533 may be referred to as a convex portion 534.

  The depth of the concave portion 533 is determined by the height of the position of the concave portion 533 (including the conductive coating film 532) and the position of the convex portion 534 (including the conductive coating film 532) when coated with the conductive coating film 532. It is desirable that the height difference is set to be about 0.5 to 2 times the average particle diameter of the toner T particles (see FIG. 5). Within this range, excessive accumulation of toner T particles at the position of the recess 533 is suppressed, so that frictional charging by the regulating blade 54 is appropriately performed and the toner T can be uniformly charged. Become. The toner T used in the present embodiment is assumed to have an average particle diameter of 1 μm to 10 μm.

  The conductive coating film 532 covers the peripheral surface including the concave portion 533 of the base material 531. As shown in FIG. 5, for example, an insulating material 532a made of an insulating resin material such as polyurethane or acrylic is carbonized. This is a layer in which a conductive material 532b such as tin oxide is dispersed. In the conductive coating film 532, the content of the conductive material 532b at the position where the concave portion 533 is formed is larger than the content of the conductive material 532b at other positions (for example, the position of the top of the convex portion 534). . Furthermore, the conductive coating film 532 has a thickness at a position where the concave portion 533 is formed larger than a thickness at another position (for example, the position of the top of the convex portion 534). In addition, the conductive coating film 532 is configured to cover the concave portion 533 and the corner portion (edge portion) of the convex portion 534 provided on the base material 531 so as to give an R shape.

  The conductive coating film 532 is formed by, for example, the conductive paint coating apparatus 100 shown in FIG. The conductive coating material coating apparatus 100 grips both ends of the base material 531 with the chuck 101, and further rotates the base material 531 around the axis while passing the slide 102 extending in the axial direction into the insulating material 532a. The coating material A in which the conductive material 532 b is dispersed is sprayed from the spray 103, and the coating material A is applied to the entire peripheral surface of the base material 531. Then, the base material 531 coated with the coating material A is heated in a heating furnace (not shown) to fix the coating material A on the base material 531, thereby forming the conductive coating film 532. In forming the conductive coating film 532, it is desirable to select a conductive material 532b whose specific gravity is larger than that of the insulating material 532a.

Next, the operation of the developing roller 53 having the above configuration will be described.
The developing device 50 of the present embodiment includes a developing roller 53 having a plurality of concave portions 533 formed on the peripheral surface and a large surface area in order to supply a sufficient amount of toner T to the photosensitive member 2. By applying a bias voltage from a bias power source (not shown), the toner T is electrically adsorbed to the peripheral surface and conveyed.

  Since the developing roller 53 of this embodiment includes a conductive coating film 532 as shown in FIG. 5, toner gradually accumulates at a position where the concave portion 533 is formed with the driving, and the concave portion 533 is formed. Clogging is suppressed. That is, since the content ratio of the conductive material 532b of the conductive coating film 532 at the position where the concave portion 533 is formed is larger than the content ratio of the conductive material 532b of the conductive coating film 532 at other positions, the concave portion 533 is formed. In the position where it is performed, more conductive material 532b is contained than in other positions. That is, the conductivity at the position is increased, and the toner T at the position is easily separated from the peripheral surface of the developing roller 53. More specifically, when a bias voltage in which the AC voltage is superimposed is applied, the toner T flies to the photosensitive member 2 before the other position because the conductivity is high at the position where the recess 533 is provided. The predetermined voltage is reached. Accordingly, the toner T at the position where the recess 533 is provided is supplied to the photoreceptor 2 with priority over the toner T at other positions. For this reason, clogging of the toner T in the concave portion 533 is suppressed, and the toner T can be stably transported over a long period of time by the developing roller 53.

Therefore, according to this embodiment described above, the developing roller 53 has a plurality of concave portions 533 formed on the peripheral surface, and has the conductive coating film 532 that covers the peripheral surface including the concave portions 533, and is conductive. The coating film 532 is a layer in which the conductive material 532b is dispersed in the insulating material 532a, and the content of the conductive material 532b at the position where the recess 533 is formed is larger than the content of the conductive material 532b at other positions. By adopting the configuration described above, it is possible to increase the conductivity at the position where the concave portion 533 is formed, thereby improving the ease of separation of the toner T due to the electrical action at the position. Furthermore, since the conductive coating film 532 of this embodiment covers the concave portions 533 and the corner portions (edge portions) of the convex portions 534 so as to give an R shape, the toner T is prevented from being caught at the edge portions. As a result, it is possible to provide an effect that the toner T is more easily separated from the peripheral surface of the developing roller 53.
Therefore, in the present embodiment, the clogging of the toner T in the concave portion 533 is prevented, so that it is possible to suppress image formation defects such as density unevenness.

  In this embodiment, the conductive coating film 532 is formed by applying the coating material A in which the conductive material 532b is dispersed in the insulating material 532a to the peripheral surface including the recess 533. By applying the coating material A to the peripheral surface including the concave portion 533 using the conductive coating material coating apparatus 100 and causing the conductive material 532b having a specific gravity larger than that of the insulating material 532a to flow into the concave portion 533 by its own weight, the concave portion 533 is formed. It becomes possible to easily manufacture the conductive coating film 532 in which the content of the conductive material 532b at the formed position is larger than the other positions.

  Further, in the present embodiment, the conductive coating film 532 employs a configuration in which the thickness at the position where the recess 533 is formed is larger than the thickness at the other position, thereby the position where the recess 533 is formed. The conductivity can be further increased by increasing the amount of the conductive material 532b.

  In the present embodiment, a developing roller that is supplied with a bias voltage on which an AC voltage is superimposed and supplies the toner T contained in the housing 51 to the photoreceptor 2 for carrying an electrostatic latent image is provided. By adopting the developing device 50 having the developing roller 53 of the present embodiment as the developing roller, it is possible to perform a stable developing operation over a long period while suppressing image formation defects. The developing device 50 is obtained.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the above-described embodiment, it has been described that the coating layer is formed by applying the coating material A in which the conductive material 532b is dispersed in the insulating material 532a to the peripheral surface including the concave portion 533. For example, a film member in which the conductive material 532b is dispersed in the insulating material 532a (the content ratio of the conductive material 532b at a position corresponding to the position where the concave portion 533 is formed in advance) is not limited to the above configuration. A structure in which the conductive material 532b is dispersed in the insulating material 532a (previously the concave portion 533 is formed) may be formed. A configuration in which the conductive material 532 b is formed so that the content rate of the conductive material 532 b at a position corresponding to the position to be formed is fitted into the base material 531 may be employed.

  DESCRIPTION OF SYMBOLS 2 ... Photosensitive body (image carrier), 50 ... Developing apparatus, 53 ... Developing roller, 532 ... Conductive coating film (coating layer), 532a ... Insulating material, 532b ... Conductive material, 533 ... Recess, A ... Paint

Claims (4)

A developing roller having a plurality of recesses formed on a peripheral surface,
Having a coating layer covering the peripheral surface including the recess,
The coating layer is a layer in which a conductive material is dispersed in an insulating material, and the content of the conductive material at a position where the concave portion is formed is larger than the content rate at other positions. roller.   The developing roller according to claim 1, wherein the coating layer is formed by applying a coating material in which a conductive material is dispersed in an insulating material to a peripheral surface including the concave portion.   The developing roller according to claim 1, wherein the coating layer has a thickness at a position where the concave portion is formed larger than a thickness at another position. A developing device having a developing roller that is supplied with a bias voltage on which an alternating voltage is superimposed and supplies toner contained therein to an image carrier for carrying an electrostatic latent image,
A developing device comprising the developing roller according to claim 1 as the developing roller.

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