JP2007010987A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the inside of an image forming apparatus from being contaminated by restraining the scattering of developer from a developing device, in such a state with the developing device being attached to the image forming apparatus body. <P>SOLUTION: The developing device 1 is a device for supplying toner to a photoreceptor drum 3 in a printer 10 and is equipped with a magnetic roller 11, a roller contacting/separating mechanism 16 and a roller driving part 12. The magnetic roller 11 has a drawing-up pole N3 for pumping the developer to a prescribed spot in its peripheral direction. The roller contacting/separating mechanism 16 is a mechanism for turning the magnetic roller 11 by a prescribed angle θ. The roller driving part 12 is a mechanism for performing aging with respect to the magnetic roller 11 that has been turned by the roller contacting/separating mechanism 16. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a developing device, and more particularly to a developing device for supplying toner to a photosensitive drum of an image forming apparatus.

  The present invention also relates to an image forming apparatus provided with such a developing device.

  An image forming apparatus that employs an electrophotographic system such as a laser printer includes a photosensitive drum on which a toner image is formed, and a developing device for supplying toner to the photosensitive drum. A developing roller is provided adjacent to the drum.

  As this type of conventional image forming apparatus, there is known an apparatus in which a developing device can be detachably attached to an image forming apparatus main body. In this type of image forming apparatus, the developing device is generally shipped separately from the main body, but the developing device is usually filled with a developer, and the developer adheres to the surface of the developing roller. It ’s easy. Therefore, after unpacking the developing device, an operation for removing the developer attached to the surface of the developing roller using a predetermined jig is usually performed.

  However, the packaging form that individually wraps the developing device increases the number of manufacturing steps, and it takes more time to unpack the container when installing the image forming apparatus and the developer filling operation, and the setup work is complicated. There is a risk of making mistakes.

  Therefore, in a relatively small image forming apparatus such as a printer-dedicated machine, in order to save the trouble of separately packaging the developing device, the developing device filled with the developer is first shipped in the state of being mounted on the main body and installed. In some cases, a method of removing the developer on the developing roller by tilting the image forming apparatus may be employed.

As related techniques, for example, those shown in Patent Documents 1 and 2 have already been proposed.
JP 2003-167424 A JP 2004-198911 A

  However, when the developing device is mounted on the image forming apparatus main body, the developer attached to the developing roller may be scattered outside the developing device and the inside of the image forming apparatus may be contaminated.

  An object of the present invention is to prevent scattering of the developer from the developing device in a state where the developing device is mounted on the main body of the image forming apparatus, and to prevent the inside of the image forming apparatus from being contaminated.

  A developing device according to a first aspect is a developing device for supplying a developer to a photosensitive drum of an image forming apparatus, and includes a first developing roller, a roller rotating mechanism, and an aging mechanism. The first developing roller has a pumping pole that pumps up the developer at a predetermined position in the circumferential direction. The roller rotation mechanism is a mechanism for rotating the first developing roller by a predetermined angle. The aging mechanism is a mechanism for aging the first developing roller rotated by the roller rotation mechanism.

  In this apparatus, in a normal use state, the developer is pumped up by the pumping pole of the first developing roller. However, when the first developing roller is rotated by a predetermined angle by the roller rotating mechanism, the pumping pole is displaced in the circumferential direction. The pumping pole can be disabled and the pumping of the developer to the first developing roller can be avoided. The first developing roller is aged by the post-rotation aging mechanism, whereby the developer already attached to the roller surface can be dropped, and the developer can be removed from the roller surface. Therefore, in this developing device, even when the image forming apparatus main body is transported while being mounted, it is possible to prevent the developer from being scattered outside the developing device and contaminating the inside of the image forming apparatus. it can.

  In addition, since the developing device can be shipped in a state of being mounted on the image forming apparatus, it is not necessary to mount the developing device individually as in the prior art, and therefore, the number of manufacturing steps of the image forming apparatus can be reduced, It is possible to shorten the work time when installing the image forming apparatus and prevent work mistakes.

  An example of the aging mechanism is a drive motor that rotates the first developing roller for a predetermined time. In addition, during aging, if there is another roller (for example, a second developing roller described later) in addition to the first developing roller, it may be rotated together.

  Further, the developer may be a one-component developer or a two-component developer. The term “developer” includes not only a single toner but also a mixture of toner and carrier in the case of a two-component system.

  According to a second aspect of the present invention, there is provided the developing device according to the first aspect, further comprising a second developing roller that is disposed between the first developing roller and the photosensitive drum and is supplied with the developer from the first developing roller. . The roller rotation mechanism further rotates the second developing roller so as to approach or retreat from the photosensitive drum with the rotation center of the first developing roller as a fulcrum.

  In this apparatus, in particular, in an apparatus that can also handle a two-component developer (hereinafter also referred to as a hybrid type), the developer is reliably removed from the first developing roller.

  In addition, since the second developing roller disposed closer to the photosensitive drum can be retracted here, it is possible to suppress contact with the photosensitive drum during the attaching / detaching operation of the developing device.

  An image forming apparatus according to a third aspect includes a photosensitive drum, a developing device, and a control unit. The developing device is an apparatus according to claim 1 or 2. The controller activates the aging mechanism of the developing device when the first developing roller is rotated by a predetermined angle by the roller rotating mechanism.

  In this apparatus, since the aging is automatically performed when the first developing roller is rotated by a predetermined angle by the roller rotating mechanism in the developing device, the developer can be reliably removed from the first developing roller.

  According to the present invention, in a normal use state, the developer is pumped up by the pumping pole of the first developing roller. When the first developing roller is rotated by a predetermined angle by the roller rotating mechanism, the pumping pole is circumferentially moved. Therefore, the pumping pole can be disabled and the pumping of the developer to the first developing roller can be avoided. The first developing roller is aged by the post-rotation aging mechanism, whereby the developer already attached to the roller surface can be dropped, and the developer can be removed from the roller surface. Therefore, according to the present invention, it is possible to prevent the developer from being scattered outside the developing device and contaminating the inside of the image forming device even when transported while being mounted on the main body of the image forming device. be able to.

  Further, according to the present invention, since it is possible to ship in a state where it is mounted on the image forming apparatus, it is not necessary to mount the developing device as in the conventional case, and accordingly, the number of manufacturing steps of the image forming apparatus can be reduced. Therefore, it is possible to shorten the work time when installing the image forming apparatus and prevent work mistakes.

<Color printer>
1 and 2 show a tandem color printer 10 including a developing device 1 in which an embodiment of the present invention is adopted.

  The printer 10 includes a printer main body 2 and a developing device 1 attached to the printer main body 2. The printer main body 2 is configured such that the developing device 1 can be detachably attached. Here, the developing device 1 can be disposed at a predetermined position in the vicinity of the photosensitive drum 3 by moving the developing device 1 toward the rear side or the front side in the axial direction. It has become.

  The printer main body 2 includes four photosensitive drums 3, intermediate transfer belts 5, control units 4, and other input / output units respectively corresponding to toners of four colors of cyan, magenta, yellow, and black. .

  Each of the photosensitive drums 3 carries a toner image of each color on the surface and transfers the toner image to the intermediate transfer belt 5.

  The intermediate transfer belt 5 is an endless belt arranged in the printer body 2 so as to extend in the horizontal direction, and is circulated and driven in accordance with an image forming operation. The toner image transferred onto the intermediate transfer belt 5 is transferred by the transfer device 8 to the paper transported from the paper feed cassette 7 or the bypass tray 9 through the paper transport path 6.

  The control unit 4 includes a microcomputer including a CPU and a memory (not shown), and various control programs executed by the CPU are stored in the memory. These control programs include a program for performing aging described later. When this program is executed, when the sleeve roller 15 is retracted by a roller contact / separation mechanism 16 described later, the control unit 4 operates the roller driving unit 12 for a predetermined time and rotates the sleeve roller 15 about several times. .

  The printer main body 2 further includes a transfer device 8, a fixing device 14, a paper feed mechanism and a paper discharge mechanism (not shown) as other input / output units.

<Developing device>
3 and 4 show the developing device 1.

  Here, only one of the four developing devices 1 will be described, but all are configured similarly except that the color of the toner used is different.

  The developing device 1 is a device for supplying toner to the photosensitive drum 3 of the printer 10, and includes a magnetic roller 11 (first developing roller), a roller driving unit 12 (aging mechanism, see FIG. 2), a blade 13, a sleeve roller 15 (second developing roller), a roller contact / separation mechanism 16 (roller rotation mechanism), two stirring members 17 and 19, and a casing 21 in which these are disposed.

  The magnetic roller 11 has five magnetic poles at predetermined positions in the circumferential direction. The magnetic roller 11 has a pumping pole N3 for pumping up the developer onto the roller surface and a peeling pole N2 for peeling off the developer from the roller surface. Contains.

  The roller driving unit 12 is for driving the magnetic roller 11 to rotate, and includes a motor or the like. Under the control of the control unit 4, the roller drive unit 12 can rotate the magnetic roller 11 along with the image forming operation, and can also perform aging of the magnetic roller 11. Aging is performed by rotating the magnetic roller 11 several times when the magnetic roller 11 is rotated by the roller contact / separation mechanism 16.

  The blade 13 is a member for trimming the developer pumped up on the magnetic roller 11, and is disposed at two positions facing both axial ends of the magnetic roller 11.

  The sleeve roller 15 is disposed close to the magnetic roller 11 and can be disposed close to the photosensitive drum 3 in the printer 10. The sleeve roller 15 is movable so as to be able to approach or retract from the photosensitive drum 3 by a roller contact / separation mechanism 16. The sleeve roller 15 is rotationally driven in accordance with the image forming operation, and can draw up toner from the developer on the magnetic roller 11.

  The sleeve roller 15 is provided with a gap roller (not shown) at both ends in the axial direction and an urging mechanism (not shown) for applying an urging force to the photosensitive drum 3 side. As a result, when the developing device 1 is mounted on the printer main body 2, the gap rollers abut against both ends of the photosensitive drum 3 in the axial direction, and the distance between the photosensitive drum 3 and the sleeve roller 15 is kept constant. Be drunk.

  The roller contact / separation mechanism 16 includes a lever member and other members (not shown) that are operated by operating the lever member, and operates the lever member when the developing device 1 is attached to or detached from the printer main body 2. Thus, the sleeve roller 15 can be retracted to avoid contact with the photosensitive drum 3, and the magnetic roller 11 can be rotated by a predetermined angle θ. At this time, the sleeve roller 15 and the magnetic roller 11 can adopt the approach state shown in FIG. 3 and the retracted state shown in FIG. 4 by operating the lever member. The approaching state is a normal state when an image forming operation or the like is performed. The sleeve roller 15 is disposed close to the photosensitive drum 3, and the magnetic roller 11 includes magnetic poles at predetermined circumferential positions. Be placed. On the other hand, in the retracted state, the sleeve roller 15 is retracted from the photosensitive drum 3 and the magnetic roller 11 is shifted in the circumferential direction so that the developer is not pumped up by the pumping pole N3. become.

  Each of the agitating members 17 and 19 is a member having a shape in which spiral blades are formed on the outer peripheral portion of the shaft, and are arranged in parallel to each other at the bottom portion in the casing 21. The agitating members 17 and 19 are rotationally driven along with the image forming operation, whereby the developer can be circulated and conveyed in the casing 21 via the partition wall 23 of the casing 21.

  The inside of the casing 21 is filled with a developer.

<Operation of developing device>
Next, the operation of the developing device 1 will be described.

  For example, when the printer 10 is manufactured after being manufactured in a factory and then shipped, the entire printer 10 is packed with the developing device 1 mounted on the printer main body 2. At this time, each developing device 1 is filled with the developer of each color and is brought into a retracted state by the roller contact / separation mechanism 16.

  More specifically, the roller contact / separation mechanism 16 operates the lever member so that the sleeve roller 15 rotates by a predetermined angle θ with the rotation center of the magnetic roller 11 as a fulcrum, and then retracts from the photosensitive drum 3. At the same time, the magnetic roller 11 also rotates by a predetermined angle θ. As a result, the magnetic poles of the magnetic roller 11 are shifted in the circumferential direction, and the pumping pole N3 moves to a position where the developer cannot be pumped.

  Then, in the developing device 1 in the retracted state, the magnetic roller 11 is rotated several times to perform aging. As a result, the developer attached to the surface of the magnetic roller 11 is removed.

  Therefore, according to the developing device 1, even if the printer 10 is transported after the aging is completed, it is possible to prevent the developer from scattering into the printer 10 and to prevent the inside of the printer 10 from being contaminated.

  Also, since the developing device 1 can be shipped with the developing device 1 mounted on the printer 10, it is not necessary to mount the developing device 1 as in the prior art. Therefore, man-hours for manufacturing the printer 10 can be reduced, and image formation can be performed. It is possible to shorten the time required for the installation work of the apparatus and prevent work mistakes.

<Other embodiments>
(A) During aging, not only the magnetic roller but also the sleeve roller may be rotated together.

  (B) The developing device of the present invention is not limited to the hybrid developing device, and can be applied to a developing device having only one developing roller.

  (C) The developing device of the present invention is not limited to a tandem color printer, but can be applied to a printer dedicated to monochrome printing or a one-drum color printer.

  (D) The image forming apparatus to which the developing device of the present invention is attached is not limited to a printer, but adopts an electrophotographic system such as a multifunction machine having other functions such as a copying function and a facsimile function. It may be.

1 is a diagram illustrating a printer in which an embodiment of the present invention is employed. FIG. 2 is a block diagram illustrating a configuration of the printer. FIG. 2 is a longitudinal sectional view showing a developing device in an approaching state mounted on a printer main body of the printer. FIG. 4 is a longitudinal sectional view showing the developing device of FIG. 3 in a retracted state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Developing apparatus 3 Photosensitive drum 4 Control part 10 Printer (image forming apparatus)
11 Magnetic roller (first developing roller)
12 Roller drive (aging mechanism)
15 Sleeve roller (second developing roller)
16 Roller contact / separation mechanism (roller rotation mechanism)
θ Predetermined angle

Claims (3)

A developing device for supplying a developer to a photosensitive drum of an image forming apparatus,
A first developing roller having a pumping pole for pumping developer at a predetermined position in the circumferential direction;
A roller rotation mechanism for rotating the first developing roller by a predetermined angle;
An aging mechanism for aging the first developing roller rotated by the roller rotation mechanism;
A developing device comprising: A second developing roller disposed between the first developing roller and the photosensitive drum, and supplied with the developer from the first developing roller;
The roller rotation mechanism further rotates the second developing roller so as to approach or retract from the photosensitive drum with a rotation center of the first developing roller as a fulcrum.
The developing device according to claim 1. A photosensitive drum;
A developing device according to claim 1 or 2,
A control unit that operates an aging mechanism of the developing device when the first developing roller is rotated by a predetermined angle by the roller rotating mechanism;
An image forming apparatus.

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