JP2018081263A - Developing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device that can effectively stir and convey a developer inside a developer container.SOLUTION: A developing device 30 comprises: a developer container 31; an upper stirring chamber 33; a lower stirring chamber 34; an upper stirring member 35; a lower stirring member 36; and a first communication path 41. The upper stirring chamber 33 and lower stirring chamber 34 are the inside of the developer container 31 storing toner divided by a partition wall part 32, and arranged at different heights in the vertical direction. The upper stirring member 35 and lower stirring member 36 are respectively rotatably supported inside the upper stirring chamber 33 and lower stirring chamber 34. The first communication path 41 is provided at one end in the axial direction of the partition wall part 32, and toner circulates from the upper stirring chamber 33 toward the lower stirring chamber 34. The first communication path 41 is provided at an end on the downstream side in the direction of rotation of the upper stirring member 35 in the width direction of the partition wall part 32 orthogonal to the axial direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a developing device and an image forming apparatus including the developing device.

  In an electrophotographic image forming apparatus such as a copying machine or a printer, an electrostatic latent image formed on the surface of a photosensitive drum as an image carrier is developed by a developing device so that a toner image to be transferred onto a sheet later can be obtained. The forming apparatus is widely used. Some developing devices include two stirring chambers and two stirring members that transport the developer while stirring. An example of such a developing device is disclosed in Patent Document 1.

  The conventional developing device described in Patent Document 1 includes a developing chamber and a stirring chamber each having a developer conveying member inside a developing container. The conveying member of the agitation chamber has a rotation axis inclined with respect to the agitation member having a horizontal rotation axis of the developing chamber. A communication path is provided through which the developer falls from the downstream portion in the developer conveyance direction of the developing chamber toward the upstream portion in the developer conveyance direction of the stirring chamber. Further, a developer replenishing port for replenishing the developer from the outside to the inside of the developing container is provided above the communication path. As a result, the developing device improves the performance of taking in the newly supplied developer into the developer inside the developing container and the dispersion performance.

Japanese Patent No. 4217671

  However, in the conventional developing device described in Patent Document 1, the developer falling from the communication path is piled up on the upper side of the stirring member in the lower stirring chamber, so that the developer is not sufficiently stirred in this region. The problem was that there was a risk of becoming. Further, since the newly replenished developer falls from above in the region of the communication path, there is a risk that mixing and dispersion of the newly replenished developer with respect to the existing developer inside the developing container may be insufficient. there were. As a result, there has been a concern that poor charging of the developer may occur, leading to a decrease in image quality.

  SUMMARY An advantage of some aspects of the invention is that it provides a developing device and an image forming apparatus capable of effectively realizing stirring and conveyance of a developer inside a developing container. .

  In order to solve the above problems, the developing device of the present invention includes a developing container, an upper stirring chamber, a lower stirring chamber, an upper stirring member, a lower stirring member, a first communication path, and a second communication path. The developing container contains a developer to be supplied to the image carrier. In the upper stirring chamber and the lower stirring chamber, the inside of the developing container is divided through a partition wall and is arranged at different heights in the vertical direction. The upper stirring member and the lower stirring member are rotatably supported in the upper stirring chamber and the lower stirring chamber, respectively, and convey the developer while stirring the developer in opposite directions along the rotation axis direction. The first communication path is provided on one end side of the partition wall in the axial direction, and the developer flows from the upper stirring chamber toward the lower stirring chamber. The second communication path is provided on the other end side of the partition wall in the axial direction, and the developer flows from the lower stirring chamber toward the upper stirring chamber. And a 1st connection path is provided in the edge part of the rotation direction downstream of an upper stirring member in the width direction of the partition part orthogonal to an axial direction.

  According to the configuration of the present invention, the inside of the developing container is divided through the partition wall, and the two agitating chambers arranged at different heights in the vertical direction are aligned with the rotation direction of the upper agitating member. The developer can be circulated along the inner wall from the upper stirring chamber toward the lower stirring chamber. This makes it possible to effectively realize the stirring and transport of the developer inside the developer container.

1 is a vertical sectional front view of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a vertical sectional front view of an image forming unit of the image forming apparatus according to the embodiment of the present invention. 2 is a vertical sectional side view of the developing device of the image forming apparatus according to the embodiment of the present disclosure. FIG. 1 is a partially enlarged vertical sectional side view of a developing device of an image forming apparatus according to an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following contents.

<First Embodiment>
First, a schematic configuration of the image forming apparatus according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is an example of a cross-sectional view illustrating a schematic configuration of an image forming apparatus. FIG. 2 is a cross-sectional view illustrating a configuration of an image forming unit of the image forming apparatus. The image forming apparatus 1 is a so-called multi-function machine having functions such as printing (copying), scanning (image reading), and facsimile transmission, and is of a color printing type in which a toner image is transferred onto a sheet using an intermediate transfer belt. .

  As shown in FIG. 1, the image forming apparatus 1 includes a document conveying unit 3 placed on the upper surface of a main body 2 and an image reading unit 4 inside the main body 2 below the image conveying unit 3. The image reading unit 4 reads an image of a document loaded on the document conveying unit 3 or an image of a document placed on a contact glass (not shown) on the upper surface of the image reading unit 4.

  An operation panel 5 is provided in the upper part of the main body 2 and on the front side of the image reading unit 4. The operation panel 5 receives a command input for executing a print (copy) job, a scan (image reading) job, a facsimile transmission job, and the like by the user. Further, the operation panel 5 displays, for example, the state of the apparatus, notes, and error messages on the display unit 5w.

  Further, the image forming apparatus 1 includes a printing unit 6 for executing a print job in a portion below the image reading unit 4 of the main body 2. The printing unit 6 includes a paper feed unit 7, a paper transport unit 8, an exposure unit 9, an image forming unit 20, a transfer unit 11, and a fixing unit 12.

  The paper feed unit 7 accommodates a plurality of sheets P, and separates and feeds the sheets P one by one during printing. The paper transport unit 8 transports the paper P sent from the paper feed unit 7 to the secondary transfer unit 11 w and the fixing unit 12, and further discharges the fixed paper P to the paper discharge unit 13. The exposure unit 9 irradiates the image forming unit 20 with laser light L controlled based on the image data.

  The image forming unit 20 is provided with four units: an image forming unit 20Y for yellow, an image forming unit 20M for magenta, an image forming unit 20C for cyan, and an image forming unit 20K for black. In the following description, the identification symbols “Y”, “M”, “C”, and “B” representing the respective colors are omitted unless particularly limited.

  As shown in FIG. 2, the image forming unit 20 has a charging unit around a photosensitive drum 21 that is an image carrier that is rotatably supported in a predetermined direction (clockwise in FIG. 2). 22, a developing device 30 and a drum cleaning unit 23 are provided. The primary transfer units 11Y, 11M, 11C, and 11K are disposed between the developing device 30 and the drum cleaning unit 23.

  The transfer unit 11 includes an intermediate transfer belt 11z, primary transfer units 11Y, 11M, 11C, and 11K, a secondary transfer unit 11w, and an intermediate transfer cleaning unit 11x. The four image forming units 20 are arranged in a so-called tandem system arranged in a line from the upstream side to the downstream side in the rotation direction of the intermediate transfer belt 11z.

  The charging unit 22 charges the surface of the photosensitive drum 21 to a predetermined potential using, for example, a charging roller. Then, an electrostatic latent image of a document image is formed on the surface of the photosensitive drum 21 by the laser light L emitted from the exposure unit 9. The developing device 30 supplies toner to the electrostatic latent image and develops it to form a toner image.

  The toner images are primarily transferred onto the surface of the intermediate transfer belt 11z by primary transfer portions 11Y, 11M, 11C, and 11K disposed above the image forming portions 20Y, 20M, 20C, and 20K for the respective colors. Then, the toner image of each image forming unit 20 is transferred to the intermediate transfer belt 11z at a predetermined timing along with the rotation of the intermediate transfer belt 11z, so that yellow, magenta, cyan, and black are printed on the surface of the intermediate transfer belt 11z. A color toner image is formed by superimposing the color toner images. The drum cleaning unit 23 removes the toner remaining on the surface of the photosensitive drum 21 after the primary transfer and cleans it.

  The color toner image on the surface of the intermediate transfer belt 11z is transferred to the paper P sent in synchronization by the paper transport unit 8 at the secondary transfer nip portion formed in the secondary transfer unit 11w. The intermediate transfer cleaning unit 11x removes the toner remaining on the surface of the intermediate transfer belt 11z after the secondary transfer and cleans it.

  The fixing unit 12 heats and presses the paper P on which the toner image is transferred to fix the toner image on the paper P. In this way, the printing unit 6 prints the original image on the paper P.

  Next, the overall configuration of the developing device 30 of the image forming unit 20 will be described with reference to FIG. Since the developing devices 30 of the respective colors have the same basic structure, the identification symbols representing the respective colors are omitted.

  As shown in FIG. 2, the developing device 30 includes a developing container 31, a partition wall 32, an upper stirring chamber 33, a lower stirring chamber 34, an upper stirring member 35, a lower stirring member 36, a developing roller 37, and a regulating blade 38. .

  The developing container 31 is a container that stores, for example, a two-component developer as a developer to be supplied to the photosensitive drum 21 that is an image carrier. In this description, the developer may be simply referred to as “toner”. The developing container 31 is formed of, for example, a synthetic resin molded product. The developing container 31 has an elongated shape in the axial direction of the photosensitive drum 21 and is arranged with its longitudinal direction horizontal.

  The partition wall 32 is provided inside the developing container 31. The partition wall portion 32 extends in a substantially horizontal direction and is provided at a substantially central portion in the vertical direction of the developing container 31. The partition wall 32 partitions the inside of the developing container 31 in the vertical direction.

  The upper stirring chamber 33 and the lower stirring chamber 34 are provided inside the developing container 31. The upper stirring chamber 33 and the lower stirring chamber 34 are formed by dividing the interior of the developing container 31 in the vertical direction by the partition wall 32. The upper stirring chamber 33 and the lower stirring chamber 34 are arranged at different heights in the vertical direction. The upper stirring chamber 33 and the lower stirring chamber 34 are arranged in the vertical direction at an angle of 45 ° to 90 ° with respect to the horizontal. The upper stirring chamber 33 is located above the developing container 31 and adjacent to the arrangement area of the developing roller 37. The lower stirring chamber 34 is disposed below the developing container 31 and in a region farther from the developing roller 37 than the upper stirring chamber 33.

  The upper stirring member 35 is disposed inside the upper stirring chamber 33. The upper stirring member 35 has a configuration in which a conveying blade 35b extending spirally along the axial direction is provided on the outer peripheral surface of a rotating shaft 35a provided between both ends in the axial direction. The upper stirring member 35 is supported by the developing container 31 so as to be rotatable about an axis extending in the horizontal direction. The upper stirring member 35 rotates counterclockwise in FIG. 2, and conveys the toner while stirring the toner along the rotational axis direction. Due to the rotation of the upper stirring member 35, the toner inside the upper stirring chamber 33 is supplied to the developing roller 37 and conveyed to the lower stirring chamber 34.

  The lower stirring member 36 is disposed inside the lower stirring chamber 34. The lower stirring member 36 has a configuration in which a conveying blade 36b extending in a spiral shape along the axial direction is provided on the outer peripheral surface of a rotating shaft 36a provided between both ends in the axial direction. The lower stirring member 36 is supported by the developing container 31 so as to be rotatable about an axis extending in the horizontal direction. The lower stirring member 36 rotates clockwise in FIG. 2 and conveys the toner while stirring the toner along the rotation axis direction. Due to the rotation of the lower stirring member 36, the toner inside the lower stirring chamber 34 is conveyed to the upper stirring chamber 33.

  The developing roller 37 is a developer carrying member disposed in a region of the upper stirring chamber 33 facing the photosensitive drum 21. The developing container 31 includes an opening 31 a at a location adjacent to the photosensitive drum 21. The developing roller 37 faces the opening 31a and is supported by the developing container 31 so as to be rotatable about an axis extending in the horizontal direction. The developing roller 37 rotates counterclockwise in FIG. A part of the circumferential surface of the developing roller 37 is located inside the developing container 31, and another part of the circumferential surface is exposed to the outside through the opening 31 a and faces the photosensitive drum 21.

  The developing roller 37 is constituted by, for example, a magnet roller in which a magnetic field generating member (not shown) made of a permanent magnet is fixed. Due to the magnetic force of the magnetic field generating member, the developing roller 37 carries toner to be supplied to the surface of the photosensitive drum 21 on its surface, and forms a toner thin layer.

  The developing roller 37, the upper stirring member 35, and the lower stirring member 36 are rotatably supported by the developing container 31 in parallel with each other. The developing roller 37, the upper stirring member 35, and the lower stirring member 36 are rotationally driven by a motor (not shown). The upper stirring member 35 and the lower stirring member 36 convey the toner while stirring the toner in opposite directions.

  The regulating blade 38 is provided close to the developing roller 37 so that the tip thereof faces the surface of the developing roller 37. The regulating blade 38 is disposed on the upstream side in the rotation direction of the developing roller 37 with respect to the region where the developing roller 37 faces the photosensitive drum 21. The regulating blade 38 is arranged with a predetermined interval between the tip thereof and the surface of the developing roller 37. The regulating blade 38 is a regulating member that regulates the amount of toner carried on the surface of the developing roller 37.

  Next, the detailed configuration of the developing device 30 will be described with reference to FIGS. 3 and 4 in addition to FIG. 3 and 4 are a vertical sectional side view and a partially enlarged vertical sectional side view of the developing device 30. FIG.

  The partition part 32 is provided with the 1st connection path 41 and the 2nd connection path 42 as shown in FIGS.

  The first communication path 41 is provided on one end side of the partition wall portion 32 in the axial direction. The first communication path 41 penetrates the partition wall portion 32 in the vertical direction, and the toner flows from the upper stirring chamber 33 toward the lower stirring chamber 34.

  The second communication path 42 is provided on the other end side opposite to the one end side where the first communication path 41 is provided in the axial direction of the partition wall portion 32. The second communication path 42 penetrates the partition wall portion 32 in the vertical direction, and the toner flows from the lower stirring chamber 34 toward the upper stirring chamber 33.

  As the upper stirring member 35 and the lower stirring member 36 rotate, the toner circulates between the upper stirring chamber 33 and the lower stirring chamber 34 via the first connecting path 41 and the second connecting path 42 of the partition wall 32. To do. As a result, the toner is stirred and charged in the upper stirring chamber 33 and the lower stirring chamber 34.

  The region of the upper stirring member 35 facing the partition wall 32 moves from the left to the right in FIG. On the other hand, the first communication path 41 is provided adjacent to the inner wall of the developing container 31 at the right end of the partition wall 32 in FIG. That is, as shown in FIG. 2, the first communication path 41 is provided at an end portion on the downstream side in the rotational direction of the upper stirring member 35 in the width direction (left-right direction in FIG. 2) of the partition wall portion 32 orthogonal to the axial direction. .

  According to this configuration, the toner can be circulated from the upper stirring chamber 33 toward the lower stirring chamber 34 along the inner wall of the developing container 31 in accordance with the rotation direction of the upper stirring member 35. As a result, it is possible to effectively agitate and convey the toner inside the developing container 31 having the above configuration.

  The lower stirring member 36 rotates in the same direction as the toner dropping direction from the first communication path 41. That is, the lower stirring member 36 rotates in a direction in which the region where the toner falls from the first communication path 41 moves downward. As a result, the toner that has passed through the first communication path 41 and has fallen into the lower stirring chamber 34 does not stay on the flow generated by the rotation of the lower stirring member 36. Therefore, the toner can be suitably conveyed and circulated inside the developing container 31.

  Further, the developing device 30 includes a supply port 51, a supply unit 52, and a supply member 53 as shown in FIGS. Note that white arrows shown in FIG. 4 indicate the direction of toner distribution.

  The replenishing port 51 is provided in the lower stirring chamber 34. The replenishing port 51 is provided in the side wall portion on the outer side in the axial direction of the lower stirring chamber 34 adjacent to the first communication path 41 and opens. New toner is supplied to the lower stirring chamber 34 from the outside of the developing device 30 through the supply port 51. When new toner is supplied to the lower stirring chamber 34 via the supply port 51, the toner that has passed through the first communication path 41 and dropped from the upper stirring chamber 33 to the lower stirring chamber 34 is newly supplied. The toner is washed away. Accordingly, it is possible to improve the toner conveyance performance inside the developing container 31. Furthermore, it is possible to suitably realize mixing and dispersion of newly supplied toner with respect to existing toner inside the developing container 31.

  The replenishment unit 52 is provided adjacent to the outside of the developing container 31. The replenishment part 52 is arrange | positioned at the axial direction outer side which separated the replenishment port 51 of the lower stirring chamber 34. As shown in FIG. New toner is introduced into the supply unit 52 from above. The inside of the replenishing part 52 communicates with the inside of the lower stirring chamber 34 via the replenishing port 51. The lower stirring chamber 34 receives toner newly supplied from the supply unit 52 via the supply port 51.

  The supply member 53 is disposed inside the supply unit 52. The replenishing member 53 has a configuration in which a conveying blade 53b that extends spirally along the axial direction is provided on the outer peripheral surface of a rotating shaft 53a provided between both ends in the axial direction. The replenishment member 53 is supported by the replenishment portion 52 so as to be rotatable about an axis extending in the horizontal direction. The replenishing member 53 conveys the toner while stirring the toner along the rotation axis direction. Due to the rotation of the replenishing member 53, the toner inside the replenishing portion 52 is conveyed to the lower stirring chamber 34. By using the replenishing member 53, it is possible to improve the performance of mixing and dispersing newly replenished toner with respect to the existing toner inside the developing container 31.

  The rotation axis of the replenishing member 53 coincides with the rotation axis of the lower stirring member 36. For example, the replenishment member 53 is composed of the same member as the lower stirring member 36. As a result, the toner transport direction by the lower agitating member 36 and the toner transport direction by the replenishing member 53 can be matched. Accordingly, the toner is transported, stirred, mixed, and dispersed in the merging area of the existing toner that passes through the first communication path 41 and the new toner that passes through the supply port 51 and is supplied to the lower stirring chamber 34. It becomes possible to further improve the performance concerning.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention can be used in a developing device and an image forming apparatus.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 20 Image forming part 21 Photosensitive drum (image carrier)
DESCRIPTION OF SYMBOLS 30 Developing apparatus 31 Developing container 32 Partition part 33 Upper stirring chamber 34 Lower stirring chamber 35 Upper stirring member 36 Lower stirring member 37 Developing roller 38 Regulator blade 41 First communication path 42 Second communication path 51 Supply port 52 Supply section 53 Supply member

Claims (6)

A developer container for containing a developer to be supplied to the image carrier;
An upper stirring chamber and a lower stirring chamber, the interior of the developing container is divided via a partition wall, and arranged at different heights in the vertical direction;
An upper stirring member and a lower stirring member that are rotatably supported in each of the upper stirring chamber and the lower stirring chamber, and convey the developer while stirring the developer in opposite directions along the rotation axis direction;
A first communication path that is provided on one end side in the axial direction of the partition wall and through which the developer flows from the upper stirring chamber toward the lower stirring chamber;
A second communication path that is provided on the other end side in the axial direction of the partition wall and through which the developer flows from the lower stirring chamber toward the upper stirring chamber;
With
The developing device, wherein the first communication path is provided at an end portion on the downstream side in the rotation direction of the upper stirring member in the width direction of the partition wall portion orthogonal to the axial direction.   The developing device according to claim 1, wherein the lower stirring member rotates in the same direction as a direction in which the developer drops from the first communication path. Provided with a replenishment port for replenishing developer from the outside to the lower stirring chamber,
The developing device according to claim 1, wherein the replenishing port is provided in a side wall portion on the outer side in the axial direction of the lower stirring chamber adjacent to the first communication path. A replenishing portion disposed on the outside in the axial direction across the replenishing port of the lower stirring chamber;
A replenishing member that is rotatably supported in the replenishing portion and conveys the developer toward the replenishing port along the rotational axis direction of the lower stirring member;
The developing device according to claim 3, further comprising:   The developing device according to claim 4, wherein a rotation axis of the replenishing member coincides with a rotation axis of the lower stirring member.   An image forming apparatus comprising the developing device according to claim 1.

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