JP2009086422A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device capable of suppressing clogging of a toner supply path with supply toner. <P>SOLUTION: The developing device includes: a toner container 19 wherein the supply toner is stored; a developing unit 21 to which the supply toner stored in the toner container 19 is supplied; the first toner supply path 30 communicating with the toner container 19, for conveying the supply toner in a nearly horizontal direction; the second toner supply path 31 communicating with the first toner supply path 30 and the developing unit 21, for conveying the supply toner from the first toner supply path 30 to the developing unit 21 in a nearly vertical direction. The opening area of the second toner supply path 31 is made larger than that of the first toner supply path 30. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a toner container in which supply toner is stored, a developing device in which the supply toner stored in the toner container is supplied, and the supply toner communicated with the toner container in a substantially horizontal direction. A first toner supply path, and a second toner supply that communicates with the first toner supply path and the developing device to convey the supply toner from the first toner supply route to the developing device in a substantially vertical direction. A developing device including the path, and an image forming apparatus including the developing device.

  Conventionally, developing devices used in image forming apparatuses such as copiers, printers, facsimiles, or multifunction devices that are functionally combined with these include yellow (Y), magenta (M), cyan (C), and the like. A plurality of developing units are arranged in parallel and one endless shape is opposed to each developing unit, such as a tandem type color printer that performs image formation using four color toners of black (K). A transfer belt (or a transport belt) is arranged, and toner is transferred to the surface of transfer paper in the transport process by the rotational movement of the transfer belt (see, for example, Patent Document 1).

  At this time, each developing device is provided with a toner sensor for detecting the toner amount in the developing device, and the replenishing toner is supplied from the toner container containing the replenishing toner to the developing device according to the detection result of the toner sensor. Will be replenished.

  On the other hand, recent image forming apparatuses are required to have improved functionality (for example, higher image quality and higher speed processing) and are required to be more compact. It is arranged to ensure compactness.

  Accordingly, the toner container described above is installed at a relatively upper part inside the main body of the image forming apparatus in order to ensure easy replacement work when the toner for replenishment stored along with the toner replenishment to the developing device runs out. It is desirable to do.

  On the other hand, it is desirable that the developing device be installed on the lower side of the endless transfer belt in consideration of the circulation of toner in the developing device.

  Accordingly, the toner container and the developing device must be arranged apart from each other in the vertical direction, and in order to replenish the replenishment toner from the toner container to the developing device, a toner replenishing path that communicates them is required. Become.

  This toner replenishment path is particularly arranged when the above-mentioned plurality of developing devices are arranged in parallel and one endless transfer belt is arranged facing each developing device, and the toner container and the developing device are separated vertically. In such a case, a transfer belt may exist between them.

  When a transfer belt exists between the toner container and the developing device, a horizontal toner replenishing path for transporting the replenishing toner in a substantially horizontal direction to avoid the transfer belt, and at least the vertical separation between the toner container and the developing device. It is necessary to form a toner replenishment path with a vertical conveyance path for conveying the replenishment toner in a substantially vertical direction by a distance corresponding to the distance.

  When the toner replenishment path is configured in two directions, such as the horizontal direction and the vertical direction, at least in the horizontal toner replenishment path extending in the horizontal direction, the replenishment toner is supplied to the upper portion of the developing device using a screw or a spiral. After the horizontal conveyance, the developer is replenished by its own weight through the vertical toner replenishment path.

  In this case, the above-described toner replenishment path is, for example, in the case of a tandem color printer or the like, from the viewpoint of reducing the number of components and downsizing the image forming apparatus main body, the above-described screws, spirals, and the like are arranged coaxially. However, it is preferable to drive them simultaneously by one drive source (conveyance drive unit).

In addition, for example, when performing monochrome printing such as monochrome mode, if the toner in the developing device of another color is continuously consumed while the developing device is not consumed, the toner deteriorates and the image density is lowered. Therefore, it is well known that the driving of the developing device that does not perform printing is stopped.
JP 09-160338 A

  However, in the developing device configured as described above, the opening area of the horizontal toner supply path is larger than the opening area of the vertical toner supply path at the boundary portion (communication portion) between the horizontal toner supply path and the vertical toner supply path. If the area is larger than the area, there is a problem that the replenishment toner that is forced to be conveyed from the horizontal toner replenishment path to the vertical toner replenishment path by a screw or a spiral is easily clogged.

  Further, when replenishing toner is replenished, the toner for replenishment is replenished to each toner replenishment path for each toner container.

  Therefore, when the replenishment toner is replenished from the toner replenishment path to the developing device, for example, when the replenishment of the replenishing toner is completed by the toner concentration detection of the toner concentration detection sensor provided in the developing device, the horizontal toner replenishment route If the replenishment toner remains, the remaining toner is unexpectedly additionally supplied to the vertical toner replenishment path when the replenishment toner is replenished to other developing devices.

  At this time, the toner for replenishment remaining in the horizontal toner replenishment path is not replenished in the vertical toner replenishment path because the toner agitation drive in the developing device is stopped. If the replenishment toner replenished unexpectedly becomes full, the replenishment toner that remains in the horizontal toner replenishment path has no place to go and is forcibly conveyed to the vertical toner replenishment path with a screw or spiral. This causes a problem that toner clogging occurs due to the pressure.

  In view of the above circumstances, an object of the present invention is to provide a developing device capable of suppressing toner clogging of replenishment toner in a toner replenishment path.

  The developing device of the present invention includes a toner container in which supply toner is stored, a developing device in which the supply toner stored in the toner container is supplied, and the supply toner in communication with the toner container. A first toner replenishing path that conveys the toner in a direction, and a first toner replenishing path that communicates with the developing device and that conveys the replenishing toner from the first toner replenishing route to the developing device in a substantially vertical direction. In the developing device having the two toner supply path, the opening area of the second toner supply path is larger than the opening area of the first toner supply path.

  At this time, the volume of the second toner supply path is preferably larger than the volume of the first toner supply path.

  In addition, the present invention can be an image forming apparatus employing a developing device having any one of the above-described configurations.

  The developing device of the present invention can suppress toner clogging of the replenishment toner in the toner replenishment path.

  Next, a developing device according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory diagram of a tandem type full-color printer as an image forming apparatus provided with a developing device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of the developing device according to an embodiment of the present invention, and FIG. It is an operation explanatory view of a developing device concerning one embodiment of the present invention.

(Overall configuration of the color printer 11)
In FIG. 1, a color printer 11 according to an embodiment of the present invention includes a paper cassette 13 that stores transfer paper (not shown) inside a printer main body 12, and a paper supply that takes out the transfer paper from the paper cassette 13. An image forming unit 15 that performs image forming processing on a transfer unit supplied from a paper unit 14, a paper feed cassette 13 or a manual feed tray (not shown), and a transfer paper supplied from the paper feed cassette 13 or a manual feed tray The image forming unit 15 includes a secondary transfer unit 17 that transfers the toner image subjected to the image forming process while being guided along the transfer paper conveyance path 16, and a fixing unit 18 that fixes the transferred toner image onto the transfer paper.

  The transfer paper onto which the toner image has been transferred by the secondary transfer unit 17 is fixed by the fixing unit 18 through the transfer paper transport path 16 and then guided to the end of the transfer paper transport path 16 to be transferred to the printer main body 12. The paper is discharged toward a paper discharge tray 12a that also serves as an upper surface.

(Configuration of the image forming unit 15)
For example, the image forming unit 15 employs a tandem method in which toners (developers) of four colors of magenta (M), cyan (C), yellow (Y), and black (K) are arranged to perform image forming processing. And a plurality of toner containers 19 that store toner for replenishing each color, and a drum that forms a toner image based on image data included in print data transmitted from a personal computer (not shown). -Shaped photoconductor 20, a developing device 21 for supplying toner to the photoconductor 20, and an endless belt-shaped intermediate transfer belt (primary transfer body) as a primary transfer body onto which a toner image formed on the photoconductor 20 is transferred 22, a primary transfer roller 23 disposed opposite to the photosensitive member 20 for each color and the intermediate transfer belt 22, and a developing device 21 on the most downstream side in the rotational movement direction of the intermediate transfer belt 22. A toner concentration detection sensor 24 disposed between the secondary transfer unit 17 and a cleaning device disposed substantially on the opposite side of the toner concentration detection sensor 24 to remove residual toner attached to the surface of the intermediate transfer belt 22. 25.

  Each photoconductor 20 has a drum shape and is disposed below the intermediate transfer belt 22 together with the developing device 21. Further, on each photoconductor 20, a charger 26, an exposure device 27, a developing device 21, a primary transfer roller 23, and a static eliminator 28 are arranged around the photoconductor 20 in this order (development process order). The image forming unit 15 is substantially constituted. In addition, a cleaning device 29 is provided between the primary transfer roller 23 and the static eliminator 28 to remove residual toner and the like attached to the surface of the photoconductor 20. Thus, the toner images of the respective colors can be carried on the surface of each photoconductor 20 based on the laser beam emitted from the exposure device 27 and the toner image can be transferred to the intermediate transfer belt 22.

  Each developing device 21 basically has the same configuration and is arranged adjacent to the lower side of the intermediate transfer belt 22 along the rotational movement direction.

  The intermediate transfer belt 22 is an endless belt disposed in the printer main body 12 so as to extend in the horizontal direction, and is circulated and driven (rotated) along with the image forming operation.

  The toner image transferred onto the intermediate transfer belt 22 at each primary transfer portion constituted by the cooperation of the photoconductor 20 and the primary transfer roller 23 passes through the transfer paper transport path 16 from the paper feed cassette 13 or the manual feed tray. Then, the image is transferred by the secondary transfer unit 17 to the transfer paper that has been conveyed.

  The toner density detection sensor 24 measures the reflection density of the toner image on the intermediate transfer belt 22 and, based on the detected value, development conditions such as toner replenishment of each developing device 21 and bias voltage applied to the developing device 21, charging device This is used to execute calibration of the charging conditions of 26, the exposure conditions such as the laser power of the exposure unit 27, the erase light quantity of the static eliminator 28, and the like.

  A plurality of toner density detection sensors 24 can be provided in the rotational direction of the intermediate transfer belt 22 and in the width direction orthogonal to the rotational direction. At this time, the toner density detection sensor 24 is preferably arranged in the vicinity of both widths because the toner density on only one side in the width direction of the intermediate transfer belt 22 cannot be dealt with in the case of one side burn.

  Further, since each toner container 19 and each developing device 21 are spaced apart from each other above and below the intermediate transfer belt 22, replenishment of replenishment toner from the toner container 19 to the developing device 21 as shown in FIG. In order to avoid the intermediate transfer belt 22, the first toner replenishment path 30 that conveys the replenishment toner in a substantially horizontal direction, and at least a distance corresponding to at least the vertical separation distance between the toner container 19 and the developing device 21. A toner replenishment path is constituted by the second toner replenishment path 31 that transports the replenishment toner.

  At this time, in the first toner supply path 30, the supply toner is conveyed by the spiral (or screw) 32. The spiral 32 is provided corresponding to each toner container 19, and rotates on the same axis and is simultaneously rotated by being shared by one drive motor 33. The drive motor 33 can also be shared by the drive motor 34 that drives a drive system for stirring and transporting the replenishment toner in the toner container 19 in the toner container 19.

  Further, the opening area of the second toner supply path 31 is set larger than the opening area of the first toner supply path 30, and the volume of the second toner supply path 31 is set larger than the volume of the first toner supply path 30. Has been.

  Hereinafter, specific examples of the developing device of the present invention will be described.

  In the toner replenishing operation in the developing device of the present invention, when the toner concentration sensor 35 installed in each developing device 21 detects that the toner in the developing device 21 is low, the toner replenishing motor (installed in the toner container 19) The toner for supply is supplied to the first toner supply path 30 by driving (not shown).

  Further, after the supply toner supplied to the first toner supply path 30 is conveyed in a substantially horizontal direction by the rotation of the spiral 32 by the drive of one drive motor 33, the second toner supply path is reached at the end point of the path. 31 is dropped by its own weight in the second toner supply path 31 and supplied to the developing device 21.

  At this time, even when the replenished toner reaches the opening surface of the second toner replenishment path 31 in the first toner replenishment path 30 in a full state, the opening area A of the first toner replenishment path 30 is shown in FIG. (A × c) and the opening area B (a × b) of the second toner supply path 31 are A <B, and the opening area B of the second toner supply path 31 is larger than that of the first toner supply path 30. Since the opening area A is larger than the opening area A, the replenishment toner is reliably conveyed from the first toner replenishment path 30 to the second toner replenishment path 31.

  Further, while the driving in the developing device 21 is stopped, the replenishing toner is supplied from the other toner container 19 by the one driving motor 33 while the replenishing toner remains in the first toner replenishing path 30. Even if the toner is replenished, the maximum amount of the replenishment toner remaining in the first toner replenishment path 30 is the amount of toner corresponding to the volume of the first toner replenishment path 30.

  Accordingly, by setting the volume D (a × b × d) of the second toner supply path 31 to C <D with respect to the volume C (a × c × e) of the first toner supply path 30, for example, Even if the replenishment toner remains in the first toner replenishment path 30 in a full state, all the replenishment toner is replenished to the second toner replenishment path 31.

  Therefore, even if the replenishment toner remaining inside the toner replenishment path 30 is forcibly conveyed by the spiral 32, the replenishment toner has no place to go, and the replenishment toner remains in the first toner replenishment path 30. Clogging is suppressed.

  In the above embodiment, the developing device of the present invention is applied to the color printer 11. However, the developing device of the present invention is applied to an image forming apparatus in general, such as a color multifunction machine having a printer function and a copying function. Of course you can.

1 is an explanatory diagram of a tandem full-color printer as an image forming apparatus including a developing device according to an embodiment of the present disclosure. FIG. It is explanatory drawing of the developing device which concerns on one Embodiment of this invention. It is an operation explanatory view of a developing device concerning one embodiment of the present invention.

Explanation of symbols

11. Color printer (image forming apparatus)
DESCRIPTION OF SYMBOLS 19 ... Toner container 21 ... Developing device 30 ... 1st toner supply path 31 ... 2nd toner supply path

Claims (3)

A toner container in which supply toner is stored; a developer in which the supply toner stored in the toner container is supplied; and a first toner that communicates with the toner container and conveys the supply toner in a substantially horizontal direction. A replenishment path, and a second toner replenishment path that communicates with the first toner replenishment path and the developing device and conveys the replenishment toner from the first toner replenishment route to the developing device in a substantially vertical direction. In the developing device provided,
The developing device according to claim 1, wherein an opening area of the second toner supply path is larger than an opening area of the first toner supply path.   2. The developing device according to claim 1, wherein the volume of the second toner supply path is larger than the volume of the first toner supply path.   An image forming apparatus comprising the developing device according to claim 1.

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