JP2013109071A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device which causes no indentation on a developing roller even if the operation of the developing device is stopped for a long time (for example, a few days) in a constitution in which a thin layer of a developer having a desired layer thickness is formed on the peripheral surface of the developing roller by regulating the layer thickness of the developer supplied on the peripheral surface of the developing roller.SOLUTION: There is provided a developing device which comprises: a developer carrier 100 for developing an electrostatic latent image formed on an image carrier 10 with a developer; layer thickness regulating means 300 by which a developer supplied from supply means 200 to the developer carrier 100 is regulated to have a constant layer thickness; and a contacting/separating mechanism 400 for contacting/separating the layer thickness regulating means 300 and the developer carrier 100, wherein the developer carrier 100, the supply means 200 and the layer thickness regulating means 300 are disposed in a body, the layer thickness regulating means 300 is supported by an attachment member 600, and the contacting/separating mechanism 400 comprises a cam 410 provided in the supply means 200 and a roller which is provided in the attachment member 600 and comes into contact with the cam 410.

Description

  The present invention relates to a developing device.

  As a developing device, there is one having a configuration described in Patent Documents 1 and 2.

In these patent documents, a layer thickness regulating roller is pressed against the developing roller to regulate the layer thickness of the developer supplied to the circumferential surface of the developing roller, and a desired layer thickness is formed on the circumferential surface of the developing roller. It forms a thin layer of developer.
JP-A-10-104944 JP-A-10-153910

  However, since the configurations of these patent documents are always configured such that the layer thickness regulating roller is pressed against the developing roller, the pressed portion of the developing roller is deformed, and a recess called an impression remains.

  In particular, when the operation of the developing device is stopped for a long time (for example, several days), a strong impression remains, and the impression appears on the developer image, and noise is generated at the output (image transferred to the transfer material). The problem of appearing.

  In order to solve the above problems, the present invention provides a developer carrier for developing a developer on an electrostatic latent image formed on an image carrier, and a developer supplied to the developer carrier from a supply means. In a developing device comprising a layer thickness regulating means for regulating a constant layer thickness, and a contact / separation mechanism for contacting and separating the layer thickness regulating means and the developer carrying body, the developer carrying body, the supplying means, and the layer thickness regulating means Is disposed in the main body, the layer thickness regulating means is supported by the attachment member, and the contact / separation mechanism includes a cam provided in the supply means, and a roller provided in the attachment member and in contact with the cam. And

  Further, the layer thickness regulating means and the developer carrying member are rollers, and the contact / separation mechanism is arranged on one side of the main body.

  According to the present invention, by forming a contact / separation mechanism by the cam provided in the supply means and the roller provided in the mounting member and in contact with the cam, the layer is always placed on the developing roller except during printing. It is no longer necessary to press the thickness regulating roller, and generation of indentation can be eliminated.

Embodiments of the present invention will be described with reference to the drawings. First, an image forming apparatus to which the developing device of the present invention is applied will be described. FIG. 1 is a schematic view of an image forming apparatus to which the developing device of the present invention is applied. In this image forming apparatus, an electrophotographic system that performs processes of charge removal, charging, exposure, development, transfer, and cleaning around the image carrier 10 is applied.

  Briefly, the charge removing means 20 for removing residual charges on the image carrier 10 around the image carrier 10 in the order of operation, the charging means 30 for charging the surface of the image carrier 10 to a specific polarity, An exposure means 40 for forming an electrostatic latent image on the image carrier 10, a developing device 50 of the present invention for developing the electrostatic latent image formed on the surface of the image carrier 10 with a developer, and the image carrier 10 It comprises transfer means 60 for transferring the developed developer to a sheet conveyed from a paper feeder (not shown). The developer transferred to the sheet is fixed to the sheet by fixing means (not shown).

Although the contact development method is described in the present embodiment, the present invention can also be applied to a non-contact development method in which development is performed without contacting the image carrier 10. Each will be described below.

  Next, the developing device of the present invention will be described. 2 and 3 are schematic views of the developing device of the present invention. The developing device includes a stirring unit 500 that stirs the developer supplied from the outside of the developing device 50 in the developing side plate 51 that accommodates the developer, a developer carrying member 100 that includes an elastic roller, and a developing unit plate 51. Supply means 200 for supplying the developer to the developer carrier 100 and a layer that is disposed in contact with the developer carrier 100 at an appropriate pressure and forms a thin layer of a constant developer on the developer carrier 100 A thickness regulating means 300 and a contact / separation mechanism 400 for separating the layer thickness regulating means 300 from the developer carrier 100 are provided.

  Agitation means 500 is provided behind supply means 200 and has a central axis 510 extending in the same direction as the axis of developer carrier 100 and agitation blades 520 provided at a plurality of positions in the axial direction on central axis 510. The stirring blade 520 rotates in a predetermined direction. The stirred developer is conveyed to the supply unit 200 side.

  The developer carrier 100 is a developing roller in which an elastic intermediate layer 120 is formed around a central axis 110 made of a conductive rigid body such as stainless steel, and rotates clockwise. Further, the developer carrying member 100 has a crown shape with a diameter reduced from the center toward the end.

  This shape is formed in order to obtain a uniform pressing force even when the roller due to its own weight bends when printing (outputting) a wide transfer material. Further, the central shaft 110 of the developer carrier 100 is connected to a power source (not shown). In the following description, the developer carrier 100 is referred to as a developing roller.

  The developing roller 100 supplies a developer to the surface of the image carrier 10 such that the thin layer formed on the developing roller 100 is pressed against the image carrier 10, and the electrostatic latent image formed on the surface of the image carrier 10 is supplied. A developer image is formed by reversal development. At the same time, the developer remaining on the surface of the image carrier 10 is collected. In this embodiment, the developer remaining on the image carrier is collected at the same time as the development. However, the present invention is not limited to this, and a configuration in which the developer is collected by a cleaner may be used.

  As described above, the supply unit 200 conveys the developer conveyed from the stirring unit 500 to the developing roller 100 side. At the same time, the residual developer that has not been supplied to the image carrier 10 is peeled off from the developing roller 100.

  For this reason, the supply means 200 includes a shaft 210 extending in parallel with the axis of the developing roller 100, and a fabric that is wound around the shaft 210 and formed of a conductive fiber (not shown) in a pile shape and is subjected to napping. Consists of. The supply unit 200 is connected to a power source (not shown).

  The layer thickness regulating means 300 is composed of a conductive or semi-conductive rotatable (rotating clockwise) roller body, and regulates the layer thickness of the developer supplied in layers on the developing roller 100 by the supply means 200. Is.

  Similar to the developing roller 100, the layer thickness regulating means 300 is connected to a power source (not shown), and is disposed upstream of the contact portion between the developing roller 100 and the image carrier 10 when viewed from the rotation direction of the developing roller 100. From the following description, the layer thickness regulating means 300 is referred to as a layer thickness regulating roller. The layer thickness regulating roller 300 may also be formed in a crown shape like the developing roller 100.

  The contact / separation mechanism 400 performs contact / separation from the developer carrier 100 to the layer thickness regulating roller 300. The details of the contact / separation mechanism 400 are shown in FIGS. 2 is a view seen from FIG. 1, and FIG. 3 is a view seen from the opposite side of FIG. In FIG. 2, the stirring means 500, the developing roller 100, and the supply means 200 except for the layer thickness regulating roller 300 are supported by a frame (not shown).

  As shown in FIG. 2, the contact / separation mechanism 400 includes a cam 410, a roller 420, and first biasing means 700. The cam 410 is attached to the shaft of the supply means 200. The layer thickness regulating roller 300 is separated from the developing roller 100 by the operation of the supply unit 200.

  The cam 410 is provided with a one-way clutch 411. The one-way clutch 411 causes the cam 410 to act in a direction in which the pressure applied by the layer thickness regulating roller 300 to the developing roller 100 is released. Specifically, it acts in the direction in which the supply means 200 is rotated in the reverse direction (the arrow direction F shown in FIGS. 2 and 3).

  The roller 420 is formed of a cylindrical member having a width with which the contact portion 412 of the cam 410 contacts, and is rotatably supported by an attachment member 600 to which the layer thickness regulating roller 300 is attached. The attachment member 600 rotates around the support shaft 601.

  Further, the auxiliary first biasing means 430 is attached to the attaching means 600. The first urging means 430 is made of an elastic body such as a pressure spring, and one end is attached to a frame (not shown) and the other end is attached to the attachment member 600. The layer thickness regulating roller 300 presses the developing roller 100 by the urging force of the first urging means 430.

  The roller 420 configured as described above receives the operation of the cam 410 and moves the layer thickness regulating roller 300 to a predetermined position around the support shaft 601 of the mounting member 600, so that the layer thickness regulating roller 300, the developing roller 100, Make contact and separation.

  Further, the first biasing means 700 is made of an elastic body such as a spring and is attached to the cam 410. The first biasing means 700 is used when the layer thickness regulating roller 300 is returned (when the layer thickness regulating roller 300 is brought into contact with the developing roller 100 from a state where the layer thickness regulating roller 300 is separated from the developing roller 100). The contact part 412 is returned to a predetermined position.

  A stirring gear 500g is provided on the central shaft 510 of the stirring means 500. Each stirring gear 500g is meshed with each other via a stirring idler gear IG3. The rotation of the agitating means 500 is performed by transmitting the rotation from the transmission mechanism G described later to the central shaft 510 disposed on the cam 410 side, the stirring idler gear IG3, and the central shaft 510 disposed on the side plate 51 side.

  The rotation of the stirring unit 500 is transmitted from the image carrier 10. The rotation of the image carrier 10 is transmitted to a developing gear 100g ′ provided on the developing roller 100, and is transmitted to a transmission mechanism G described below.

  Next, the opposite side of FIG. 2 is as shown in FIG. Here, the replenishment of the developer is performed by mounting the toner cartridge TC. As shown in FIG. 3, the transmission mechanism G has a first transmission path P1 and a second transmission path P2 with the rotation of the developing roller 110 as the center.

  The first transmission path P <b> 1 transmits the rotation of the developing roller 110 to the layer thickness regulating roller 300. Specifically, this rotation is transmitted from the developing gear 100g provided on the developing roller 110 to the layer thickness regulating roller 300g provided on the layer thickness regulating roller 300 via the first idler gear IG1.

  The first idler gear IG1 and the layer thickness regulating roller are rotatably supported by the mounting member 600, respectively. In particular, the support of the first idler gear IG1 is supported by a support shaft 601 that rotatably supports the mounting member 600. With the support shaft 601 as a fulcrum, the developing roller 100, the first idler gear IG1, and the layer thickness regulating roller 300 are It always rotates while meshing.

  Further, the force that presses the layer thickness regulating roller 300 against the developing roller 100 utilizes the biting force when each gear rotates. Further, a regulation roller 800 is provided at each end of the developing roller 100 and the layer thickness regulating roller 300 so that the layer thickness regulating roller 300 is not excessively pressed against the developing roller 100.

  Further, the attachment member 600 is provided with second urging means 440. The second urging means 440 is made of an elastic body such as a spring, and separates the layer thickness regulating roller 300 from the developing roller 100.

  On the other hand, the second transmission path P <b> 2 transmits the rotation of the developing roller 110 to the supply unit 200 and the stirring unit 500. Specifically, this rotation is transmitted from the development gear 100g to the supply gear 200g provided in the supply means 200 via the second idler gear IG2.

  Further, the rotation transmitted to the supply gear 200g provided in the supply means 200 is transmitted to the central shaft 510, and again returns to FIG. 2, but is transmitted to the stirring idler gear IG3, and the stirring gear 500g disposed on the side plate 51 side. , The central axis 510 on the side plate 51 side rotates.

  Based on the above configuration, the operation of the contact / separation mechanism 400 will be described. First, when the output (printing) is completed, the image carrier 10 is reversed (arrow direction A) to a predetermined angle. The angle is specifically about 20 °. Although the operation of the contact / separation mechanism 400 has been described at the end of output (printing), the image forming apparatus may be temporarily stopped or stopped, or may be arbitrarily set by the user, and is not limited thereto. Never happen.

  As shown in FIG. 2, when the image carrier 10 is reversely rotated by a drive source (not shown), the rotation is transmitted to the developing gear 100g ′, and the developing roller 100 rotates in the arrow direction B. As shown in FIG. 3, the rotation around the developing roller 100 is shifted to the first transmission path P1 and the second transmission path P2 by the development gear 100g.

  As shown in FIG. 3, in the first transmission path P1, the rotation of the developing roller 100 is transmitted to the first idler gear IG1 and rotates in the arrow direction C, and accordingly, the layer thickness regulating roller 300 in the arrow direction D. Rotates.

  On the other hand, in the second transmission path P2, as shown in FIG. 3, the rotation of the developing roller 100 is transmitted to the second idler gear IG2, and by this transmission, the second idler gear IG2 rotates in the arrow direction E. Following the rotation of the second idler gear IG2, the supply gear 200g rotates in the arrow direction F and is further transmitted to the stirring means 500.

  At the same time as this operation, when the supply means 200 rotates in the arrow direction F in FIG. 2, the one-way clutch 411 of the cam 410 provided in the supply means 200 is operated, and the cam 410 is centered on the rotation shaft 413 of the supply means 200. Is swung in the arrow direction G.

By the swing of the cam 410, the mounting member 600 rotates in the arrow direction H with the support shaft 601 as a fulcrum, and the layer thickness regulating roller 300 is separated from the developing roller 100.
At this time, the rotational force of the cam 410 acting in the arrow direction G acts stronger than the urging force of the auxiliary first urging means 430.

  Next, at the start of printing, the image carrier 10 is rotated in the direction opposite to the arrow direction A (forward rotation). As shown in FIG. 3, the rotation of the image carrier 10 is transmitted to the developing roller 100. This transmission rotates the developing roller 100 in the direction opposite to the arrow direction B.

  With the rotation of the developing roller 100, this rotation acts on the first transmission path P1 and the second transmission path P2.

  In the first transmission path P1, the rotation of the developing roller 100 is transmitted to the first idler gear IG1, and the layer thickness regulating roller 300 rotates in the direction opposite to the arrow direction D. This rotational force is larger than the urging force of the second urging means 440, and the mounting member 600 rotates about the support shaft 601 in the direction opposite to the arrow direction H. By this operation, the layer thickness regulating roller 300 comes into contact with the developing roller 100 at a predetermined position.

  Further, in the first transmission path P2, the rotation of the developing roller 100 is transmitted to the second idler gear IG2, and the second idler gear IG2 rotates in the direction opposite to the arrow direction E by this transmission. Following this rotation of the second idler gear IG2, the supply gear 200g rotates in the reverse direction of the arrow F and is further transmitted to the stirring means 500.

  At the same time, the supply means 200 rotates in the direction opposite to the arrow direction F as shown in FIG. At this time, the one-way clutch 411 of the cam 410 does not operate and idles. The biasing force of the first biasing means 700 acts on the cam 410 in the arrow direction I.

  The biasing force of the first biasing means 700 causes the cam 410 to swing in the direction opposite to the arrow direction G, and the mounting member 600 rotates about the support shaft 601 in the direction opposite to the arrow direction H. By this operation, the layer thickness regulating roller 300 comes into contact with the developing roller 100 at a predetermined position.

  Further, the attachment member 600 is pressed by the urging force of the sub first urging means 430 to press the layer thickness regulating roller 300 against the developing roller 100 with a predetermined pressure.

  As described above, the layer thickness can be increased for a long time by separating the developing roller 100 from the layer thickness regulating roller 300 at the end of output (printing), temporarily stopping or stopping the image forming apparatus, or arbitrarily setting by the user. Indentation caused by pressing the regulating roller 300 against the developing roller 100 can be prevented.

1 is a schematic view of an image forming apparatus to which a developing device of the present invention is applied. 1 is a schematic diagram of a developing device of the present invention. FIG. 3 is a schematic view of a contact / separation mechanism viewed from the opposite side of FIG. 2.

10 Image carrier 100 Developer carrier (developing roller)
200 Supply means 300 Layer thickness regulating means (layer thickness regulating roller)
400 Contact / separation mechanism 410 Cam 420 Roller 600 Mounting member

Claims (3)

A developer carrying member that develops the developer on the electrostatic latent image formed on the image carrying member, and a layer thickness regulating unit that regulates the developer supplied from the supply unit to the developer carrying member to a constant layer thickness; In the developing device comprising a contact / separation mechanism for contacting and separating the layer thickness regulating means and the developer carrier,
The developer carrier, the supply means and the layer thickness regulating means are disposed in the main body,
The layer thickness regulating means is supported by a mounting member,
The developing device according to claim 1, wherein the contact / separation mechanism includes a cam provided in the supply unit, and a roller provided in the attachment member and contacting the cam.   2. The developing device according to claim 1, wherein the layer thickness regulating means and the developer carrying member are rollers.   The developing device according to claim 1, wherein the contact / separation mechanism is disposed on one side of the main body.

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