JP2018031858A - Developing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a reduced space when a toner density sensor is used in a developing device.SOLUTION: A developing device 230 comprises: a developer storage part 52 that stores a developer containing a toner; a toner density sensor 57 that has a detection surface 571 formed thereon detecting the density of the toner; and an opening 513 that is formed in a bottom wall part 512 of the developer storage part 52 and to which the toner density sensor 57 is attached. The toner density sensor 57 is inserted and attached to the opening 513 so that the detection surface 571 becomes a top face, and forms part of an outer wall of the developer storage part 52.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a developing device and an image forming apparatus, and more particularly to a technique for attaching a toner concentration sensor that detects the concentration of toner in a developer to a developer accommodating portion.

  In the image forming apparatus, in order to form a stable quality toner image, it is necessary to maintain the toner concentration in the developer in an appropriate range in the developing device provided in the image forming apparatus. Therefore, conventionally, the image forming apparatus is provided with a toner density sensor.

  In recent years, from the viewpoint of cost reduction and space saving, a substrate type toner density sensor having a detection surface formed by a planar pattern of a coil has been used. For example, the substrate type toner density sensor is attached such that its detection surface is in close contact with the outer wall of the developing device. Japanese Patent Application Laid-Open No. 2004-228561 describes that a substrate type toner density sensor is pressed by a pressing member via an elastic member, and the toner density sensor is brought into close contact with the outer wall of the developing device. Patent Document 2 below describes that a substrate type toner density sensor is provided with an adhesive layer, and the toner density sensor is attached to the outer wall of the developing device by the adhesive force of the adhesive layer.

JP 11-143209 A JP-A-2015-001617

  In the technique described in Patent Document 1 described above, it is necessary to provide a pressing member that presses the toner concentration sensor from a surface opposite to the installation surface on the outer wall of the developing device. In the technique described in Patent Document 2, it is necessary to provide a holding member that holds the toner density sensor attached to the outer wall of the developing device so that the adhesive layer is not peeled off. For this reason, in the techniques described in Patent Documents 1 and 2 described above, the effect of thinning the toner density sensor as a substrate type is not fully utilized for space saving.

  The present invention has been made in view of the above circumstances, and an object thereof is to further reduce the space for a developing device using a substrate type toner density sensor.

  A developing device according to one aspect of the present invention includes a developer accommodating portion that accommodates a developer containing toner, and a substrate-like toner concentration sensor on which a detection surface for detecting the toner concentration is formed, and the developing device The toner density sensor is attached with the detection surface facing the developer accommodating portion, and is inserted into an opening formed in a wall portion of the developer accommodating portion and allowing the inside of the developer accommodating portion to pass through the outside. The toner density sensor attached to the opening forms a part of the outer wall of the developer accommodating portion.

  An image forming apparatus according to an aspect of the present invention forms a toner image with the developing device and toner supplied from the developing device to an electrostatic latent image on a photosensitive member, and transfers the toner image. And an image forming unit that forms an image on the recording medium.

  According to the present invention, the toner concentration sensor is inserted and attached to the opening formed at the bottom of the developer accommodating portion, and the toner concentration sensor forms a part of the outer wall of the developer accommodating portion. As a result, the substrate-like toner density sensor is not attached to the outside of the developer accommodating portion as in the prior art, so that space can be saved.

1 is a schematic partial cross-sectional front view showing the structure of an image forming apparatus according to a first embodiment of the present invention. It is sectional drawing which showed the image development apparatus. 4A and 4B are schematic diagrams illustrating a toner density sensor, where FIG. 5A is a perspective view, FIG. 5B is a plan view, and FIG. 4A and 4B are schematic views showing an opening and its periphery when a toner density sensor is not attached, where FIG. 5A is a perspective view, FIG. 5B is a plan view, and FIG. (D) is a DD line sectional view. FIG. 4 is a schematic view showing an opening and its periphery in a state where a toner density sensor is attached, (A) is a perspective view, (B) is a plan view, and (C) is a bottom view. (D) is a DD line sectional view. FIG. 6 is a schematic plan view showing a state where a protective tape is attached to a detection surface of a toner concentration sensor.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a developing device and an image forming apparatus including the developing device according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic partial cross-sectional front view showing the structure of the image forming apparatus according to the first embodiment of the present invention. The image forming apparatus 1 is a multifunction machine having a plurality of functions such as a copy function, a printer function, a scanner function, and a facsimile function, for example, and includes an operation unit 47, a document feeding unit 6, and a document in the apparatus main body 11. The image forming unit 12 includes a reading unit 5, an image forming unit 12, a fixing unit 13, and a paper feeding unit 14.

  The operation unit 47 receives instructions such as an image forming operation execution instruction and a document reading operation execution instruction from the operator for various operations and processes that can be executed by the image forming apparatus 1, and displays operation guidance and the like to the operator. The display unit 473 is provided.

  A case where a document reading operation is performed in the image forming apparatus 1 will be described. The document reading unit 5 optically reads an image of the document fed by the document feeding unit 6 or the document placed on the document placing glass 161, and generates image data. The image data generated by the document reading unit 5 is stored in a built-in HDD (Hard Disk Drive), a network-connected computer, or the like.

  A case where an image forming operation is performed in the image forming apparatus 1 will be described. The image forming unit 12 is fed from the paper feeding unit 14 based on image data generated by the document reading operation, image data stored in the built-in HDD, image data received from a computer connected to the network, and the like. A toner image is formed on a sheet P as a recording sheet (recording medium).

  The image forming unit 12 includes a photosensitive drum 121 for black, yellow, cyan, and magenta, a charging device 220 that charges the surface of the photosensitive drum 121, and a developing device 230 that forms a toner image on the photosensitive drum 121. . The photosensitive drum 121 is driven to rotate counterclockwise in the drawing.

  FIG. 2 is a cross-sectional view showing the developing device 230, as viewed from the back side of the image forming apparatus 1 shown in FIG. The developing device 230 includes a housing 51, and a developer containing portion 52 that contains a developer containing toner is formed inside the housing 51. Inside the housing 51, a developing roller 53 is provided above the developer accommodating portion 52 so as to be opposed to the photosensitive drum 121. In addition, a regulation blade 54 is provided inside the housing 51 so as to face the developing roller 53.

  The developer accommodating portion 52 is divided into a first accommodating portion 521 and a second accommodating portion 522 by a partition wall 511 formed integrally with the housing 51 and extending in the longitudinal direction (the depth direction in FIG. 2). A first spiral feeder 55 is rotatably supported by the first storage portion 521, and a second spiral feeder 56 is rotatably supported by the second storage portion 522. A communication port (not shown) is provided at both ends in the longitudinal direction of the partition wall 511, and the first storage portion 521 and the second storage portion 522 communicate with each other through the communication port.

  The first spiral feeder 55 agitates the developer replenished from the developer container (not shown) to the first storage portion 521 and rotates in the axial direction by rotating around the axis. The conveyed developer moves from the first storage unit 521 to the second storage unit 522 through the communication port.

  The second spiral feeder 56 agitates the developer moved from the first storage unit 521 to the second storage unit 522 and rotates in the axial direction by rotating around the axis. The conveyed developer moves from the second storage portion 522 to the first storage portion 521 through the communication port. Accordingly, the developer is circulated and conveyed between the first storage unit 521 and the second storage unit 522.

  The developing roller 53 includes a magnet (not shown) inside, draws up the developer from the developer container 52 by the magnetic force of the magnet, and carries the developer on the peripheral surface. The regulating blade 54 regulates the developer carried on the peripheral surface of the developing roller 53 to a predetermined layer thickness. The regulating blade 54 is spaced from the developing roller 53 by a predetermined interval in the housing 51. It is supported.

  The toner density sensor 57 will be described with reference to FIG. 3 in addition to FIG. 3A and 3B are schematic views showing the toner density sensor 57, where FIG. 3A is a perspective view, FIG. 3B is a plan view, and FIG. 3C is a bottom view.

  An opening 513 is formed in the bottom wall portion 512 of the first storage portion 521 (developer storage portion 52) to allow the inside of the first storage portion 521 to be inserted into the outside. A toner concentration sensor 57 is inserted and attached to the opening 513. The toner density sensor 57 has a detection surface 571 on which a planar pattern of coils is formed. The toner density sensor 57 detects the toner density by the detection surface 571. The toner concentration sensor 57 further includes a connector 572. The toner density sensor 57 is attached to the opening 513 so that the detection surface 571 faces the inside of the developer accommodating portion 52. Although details will be described later, a protective tape 58 (FIG. 6) is attached so as to cover the detection surface 571 of the toner concentration sensor 57 and its periphery.

  The toner density sensor 57 detects the toner density (T / C, the ratio of carrier to toner) in the developer container 52 by the detection surface 571 exposed in the developer container 52. The toner concentration sensor 57 includes a magnetic detection device that detects a change in magnetic permeability in the developer, and detects the change in magnetic permeability as the concentration of toner in the developer container 52. The toner density sensor 57 is a so-called substrate type. The toner concentration sensor 57 has a detection surface 571 for detecting the toner concentration, and includes a connector 572 on a surface opposite to the detection surface 571.

  A coil plane pattern CP is formed on the detection surface 571. A detection signal indicating the toner density detected by the plane pattern CP is output to a connector 572 for outputting the detection signal to the outside.

  FIG. 4 is a schematic view showing the opening 513 formed in the bottom wall portion 512 (of the first storage portion 521) and the periphery thereof in a state where the toner density sensor 57 is not attached. 4A is a perspective view of the opening 513 and its periphery as viewed from the inside of the developer accommodating portion 52, FIG. 4B is a plan view thereof, FIG. 4C is a bottom view thereof, and FIG. Is a sectional view taken along the line DD.

  FIG. 5 is a schematic view showing the opening 513 formed in the bottom wall portion 512 (of the first storage portion 521) and the periphery thereof with the toner concentration sensor 57 attached thereto. It is a perspective view, (B) is the top view, (C) is the bottom view, (D) is the DD sectional view taken on the line.

  As shown in FIGS. 4 and 5, an opening 513 is formed in the bottom wall portion 512 so that the toner density sensor 57 can be fitted therein. Further, the bottom wall portion 512 is provided with a holding portion 510 that is formed integrally with the housing 51 (FIG. 2) and extends inwardly from the lower end portion 513 a of the opening 513. The holding unit 510 includes a plurality of holding unit pieces 514. Each of the plurality of holding portion pieces 514 extends outward from the outer wall of the bottom wall portion 512 of the developer accommodating portion 52 that forms both sides of the opening portion 513, and is attached to the opening portion 513. The toner density sensor 57 is held by supporting the side and the lower part. The holding piece 514 is formed at a position where the toner density sensor 57 does not interfere with the connector 572 when and after the toner density sensor 57 is attached to the opening 513.

  For example, the toner concentration sensor 57 is attached to the opening 513 from the inside of the developer accommodating portion 52, that is, from the inside of the first accommodating portion 521 (FIG. 2). In the example shown in FIG. 2, the internal height h of the holding portion piece 514, which is the distance from the inner bottom portion of the first storage portion 521 to the inner bottom portion of the holding portion piece 514, is the same as the thickness t of the toner concentration sensor 57. Has been. Note that the thickness h of the housing 51 and the thickness t of the toner concentration sensor 57 may be the same dimension. 3 to 6, an example in which the thickness h of the housing 51 and the thickness t of the toner density sensor 57 are matched is described. Thereby, the height of the inner bottom portion of the first storage portion 521 and the detection surface 571 of the toner density sensor 57 are made to coincide. As a result, the toner concentration sensor 57 can be attached to the opening 513 without hindering smooth circulation of the toner and the carrier. In addition, the protective tape 58 can be stably attached to the detection surface 571 of the toner concentration sensor 57 and its periphery at the inner bottom portion of the first storage portion 521.

  FIG. 6 is a schematic plan view showing a state where the protective tape 58 is attached to the detection surface 571 of the toner concentration sensor 57. In FIG. 6, the protective tape 58 is indicated by a one-dot chain line. A protective tape 58 is attached so as to cover the detection surface 571 of the toner concentration sensor 57 and the upper surface of the bottom wall portion 512 around the detection surface 571. Thereby, the confidentiality of the developer storage unit 52 can be maintained, and the developer can be prevented from leaking from the gap S between the toner concentration sensor 57 and the opening 513. In addition, as the protective tape 58, ultra high molecular weight polyethylene can be used suitably, for example, the brand name "Ultra Tape" by 3M Japan Ltd. is used.

  As described above, according to the embodiment, the toner density sensor 57 is inserted into the opening 513 formed in the bottom wall portion 512 of the first storage portion 521 (developer storage portion 52) from the inside of the first storage portion 521. The toner density sensor 57 is attached and becomes a part of the outer wall of the developer accommodating portion 52. That is, in the above-described embodiment, the toner density sensor 57 is not provided outside the developer accommodating portion 52 as in the prior art, but becomes a part of the outer wall of the developer accommodating portion 52, so that space saving is achieved. be able to. Further, since there is no need for the toner concentration sensor 57 to be in close contact with the outer wall of the developer accommodating portion 52 as in the prior art, a member required for the close contact is not required, and thus the space for the member is further reduced. Can be achieved.

  The toner density detection accuracy is related to the distance between the detection surface 571 and the developer. When the toner concentration sensor 57 is brought into close contact with the developer accommodating portion 52 from the outside and the toner concentration is detected by the toner concentration sensor 57 via the bottom wall portion 512 of the first accommodating portion 521 as in the prior art, the toner concentration detection is performed. Are affected by the thickness of the housing 51 (for example, 1 mm) and the variation in the thickness of the housing 51 (about ± 0.2 mm).

  In the above-described embodiment of the present invention, the detection surface 571 is in contact with the developer contained in the developer containing portion 52 only through the protective tape 58 that is much thinner than the housing 51. Detection is possible.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. In the above embodiment, an example in which the opening 513 that allows the inside of the first storage portion 521 to be inserted into the outside is formed in the bottom wall portion 512 of the first storage portion 521 (developer storage portion 52). The position of 513 is not limited to this, and other positions on the inner wall of the first housing portion 521, for example, a side wall part or an inclined inner wall part formed from the side wall part to the bottom wall part 512, An opening 513 may be formed.

  In the above embodiment, the configuration and processing shown in the above embodiment using FIGS. 1 to 6 are only one embodiment of the present invention, and the present invention is not limited to the configuration and processing.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 52 Developer accommodating part 57 Toner density sensor 58 Protection tape 230 Developing apparatus 512 Bottom part 513 Opening part 514 Holding part 571 Detection surface 572 Connector

Claims (6)

A developer accommodating portion for accommodating a developer containing toner;
A substrate-like toner concentration sensor on which a detection surface for detecting the toner concentration is formed;
The toner concentration sensor is attached with the detection surface facing the developer accommodating portion, which is inserted into an opening formed in a wall portion of the developer accommodating portion and allowing the inside of the developer accommodating portion to be inserted into the outside. ,
A developing device in which the toner density sensor attached to the opening forms a part of an outer wall of the developer accommodating portion.   The toner is extended to the outside from the outer wall of the wall of the developer accommodating portion, which is both sides of the opening, and supports the side and lower portions of the toner density sensor attached to the opening, and the toner The developing device according to claim 2, further comprising a holding unit that holds the density sensor. The toner concentration sensor has a connector provided on a surface opposite to the detection surface,
The developing device according to claim 2, wherein the holding unit is formed at a position where the holding unit does not interfere with the connector in a state where the toner density sensor is attached to the opening.   The developing device according to claim 1, wherein a protective tape that covers the detection surface of the toner concentration sensor and an upper surface of the wall portion around the detection surface is attached.   The developing device according to claim 4, wherein the protective tape is made of high molecular weight polyethylene. A developing device according to any one of claims 1 to 5,
An image forming unit that forms a toner image with toner supplied from the developing device and supplied to the electrostatic latent image on the photosensitive member, and forms an image on a recording medium by transferring the toner image; Image forming apparatus.