JP4025980B2 - Developing device in electrophotographic apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a developing device in an electrophotographic apparatus used for a copying machine, a printer, a facsimile, a composite machine thereof, and the like, and in particular, a developing roller having a mixing roller and a developing roller for stirring a developer is opposed to a photosensitive drum. The present invention relates to a developing device in an electrophotographic apparatus in which a space can be effectively used in an electrophotographic apparatus having a developing device arranged to be supplied from a toner container such as a toner container.
[0002]
[Prior art]
In recent years, electrophotographic apparatuses used for copying machines, printers, facsimiles, and multi-functional machines have been required to be downsized and reduced in price with the demand for personalization. However, for example, a color electrophotography in which a developing roller corresponding to a plurality of colors having a mixing roller and a developing roller for stirring the developer is arranged around the photosensitive drum , and toner is supplied to each developing tank from a toner container. in apparatus, even when the size of the photosensitive drum in accordance with the demand for miniaturization of the electrophotographic apparatus, can not be effectively utilized space for the toner container is large supplies toner to the developing tank of each color electrophotography There arises a problem that the device itself cannot be miniaturized.
[0003]
In other words, a developing device in an electrophotographic apparatus used for a copying machine, a printer, a facsimile machine, or a combination machine thereof uses a toner container to replenish toner consumed by image formation. It is necessary to mix the agitated toner, the developer in the developing tank, and the toner remaining on the photosensitive drum without being transferred to the recording medium, and agitate the toner to be appropriately charged. Therefore, for example, in JP-A-8-50405, JP-A-10-69155, JP-A-10-198148, etc., the replenished toner, the developer in the developing tank, and the recording medium or intermediate transfer member are disclosed. In order to mix the toner that has not been transferred and remains on the photosensitive drum , developing devices including various developer conveying devices and stirring devices have been proposed.
[0004]
The toner supply from the toner container is generally performed directly above the mixer disposed in the developing tank so that the developer remaining in the developing tank or the toner remaining on the photosensitive drum and the supplied toner are mixed well. It is preferable that the supply port of the toner container comes. In other words, when toner is supplied to a position away from the mixer, a toner pool is created, which remains unstirred for a long time, deteriorates or solidifies, or develops with a developer having a low toner concentration, resulting in image defects. Occur. Therefore, as shown in FIG. 7, the conventional developing apparatus has a toner container 73 disposed on a developing tank 72 having a mixer 70 and a developing roller 71 for stirring the developer, and a toner supply port 74 is provided in the mixer. It is common to make it come in the vicinity of 70.
[0005]
[Problems to be solved by the invention]
However, the volume of the toner container is relatively large. As described above, in the color electrophotographic apparatus in which the developing tanks for the respective colors are arranged around the photosensitive drums which are miniaturized in response to the demand for miniaturization of the electrophotographic apparatus, If an attempt is made to arrange a toner container for supplying toner directly above the mixer in the tank, a large space is required above the developing tank, which causes a problem that the electrophotographic apparatus itself is increased in size. However, the devices disclosed in the above-mentioned JP-A-8-50405, JP-A-10-69155, JP-A-10-198148, etc. are not suggested at all for dealing with these problems. .
[0006]
Therefore, in the present invention, the space in the electrophotographic apparatus is effectively used, and the supplied toner remains on the photosensitive drum without being transferred to the developer in the developing tank, the recording medium, and the intermediate transfer member. It is an object to provide a developing device in an electrophotographic apparatus having a simple and inexpensive configuration that can be reliably mixed and stirred with toner.
[0007]
[Means for Solving the Problems]
Therefore, in the present invention, as described in claim 1,
A developing roller which is disposed at a position opposed to the photosensitive light drum for developing the latent image, agitating it the parallel and developing roller, a developing tank screw mixers for transporting is accommodated, the In the developing device in the electrophotographic apparatus having a toner container disposed in parallel to the developing tank longitudinal direction on the developing tank back side opposite to the photosensitive drum through the developing tank ,
A conveyance opening path connecting the toner container and the developing tank is formed from the central position in the screw mixer axial direction toward the toner container, and the toner conveyance screw is accommodated in the conveyance opening path, and the toner conveyance the outlet end of the screw, dammed toner conveyed rises from the bottom portion to the developing tank side of the transport opening path, that the partition wall to send the toner by overflow from the top to the top of the screw mixer is provided Features.
[0008]
Thus, the toner container is positioned directly above the developing tank by providing the toner conveying opening having the toner conveying screw for supplying the toner in the direction perpendicular to the central part of the screw mixer of the developing tank from the toner container to the developing tank. The toner container can be installed at a position separated from the developing tank by the amount corresponding to the toner conveyance opening . In addition, a toner container is provided above the conventional screw mixer by damming the toner rising from the bottom to the developing tank side and providing a partition wall that overflows from the top and feeds the toner to the top of the screw mixer. As in the case, it is possible to reliably mix and stir the supplied toner, the developer in the developing tank, and the toner remaining on the photosensitive drum without being transferred to the recording medium or the intermediate transfer member, and As described above, since it is not necessary to position the toner container above the developing tank, it is possible to provide a developing device in an electrophotographic apparatus that effectively uses the space in the electrophotographic apparatus with a simple and inexpensive configuration.
[0009]
According to the second aspect of the present invention, it is preferable that an opening portion extending in the longitudinal direction of the toner container is provided on the entrance side of the conveyance opening path, and the opening portion is provided at a position facing the toner container replenishment portion.
[0010]
In this way, by using the partition wall as a developer tank side bearing of the toner conveying screw shaft, there is no need to provide a special member as the partition wall , and an electronic device that effectively uses the space in the electrophotographic apparatus with a simple and inexpensive configuration. A developing device in a photographic apparatus can be provided.
[0011]
[0012]
By providing the toner container on the upper side of the toner conveying screw, it is unnecessary to provide a special conveyance means to the toner conveying screw from the toner container, easy, and effective use of space in the electrophotographic apparatus with an inexpensive configuration A developing device in an electrophotographic apparatus can be provided.
[0013]
[0014]
[0015]
[0016]
[0017]
[0018]
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. This is just an example.
[0020]
FIG. 1 is a schematic sectional view showing the arrangement of a developing tank and a toner container around a photosensitive drum in an embodiment of an electrophotographic apparatus provided with a developing device according to the present invention, and FIG. 2 is an electrophotographic image according to the present invention. 3 is a detailed sectional view of an embodiment of the developing device in the apparatus, FIG. 3 is a perspective view of an embodiment of the developing tank and the toner conveyance opening constituting the developing device in the electrophotographic apparatus according to the present invention, and FIG. FIG. 5 is a perspective view of the toner conveying opening path from the developing tank side constituting the developing device in the electrophotographic apparatus. FIG. 5 shows another developing tank and toner conveying opening path constituting the developing apparatus in the electrophotographic apparatus according to the present invention. FIG. 6 is a perspective view of the toner conveyance opening from the developing tank side constituting another embodiment of the developing device in the electrophotographic apparatus according to the present invention. In the following description, a color electrophotographic apparatus will be described as an example, but it is obvious that the present invention can be applied not only to a color electrophotographic apparatus but also to a monochrome electrophotographic apparatus.
[0021]
In the figure, 1 is a photosensitive drum composed of amorphous silicon (abbreviated as a-Si), an organic photosensitive drum (OPC), and the like, 2 is a charger for the photosensitive drum 1, and 3 to 6 are, for example, yellow (Y) 3. Developing tanks corresponding to magenta (M) 4, cyan (C) 5, and black (K) 6 colors, 7 to 9 are toner containers as toner containers, and 10 is a toner container from toner container 9 to developing tank 5. A toner conveyance opening path 11 for conveyance is an intermediate transfer body for transferring a toner image formed on the photosensitive drum 1.
[0022]
2 to 6 show details of the cyan (C) developing tank and the toner container 9 indicated by 5 in FIG. 1, and details of the toner conveying opening 10 for conveying the toner from the toner container 9 to the developing tank 5 (FIG. 2). ), A perspective view of the developing tank 5 and the toner transport opening 10 (FIG. 3), and a perspective view of the toner transport opening 10 viewed from the developing tank 5 side (FIG. 4). FIG. 5 and FIG. 1. Details of another embodiment (FIG. 5) of the cyan (C) developing tank and the toner container 9 indicated by 5 in FIG. 1 and the toner transport opening 10 for transporting toner from the toner container 9 to the developing tank 5; FIG. 6 is a perspective view (FIG. 6) of the toner conveyance opening path 10 as viewed from the developing tank 5 side. In the figure, 20 is a developing roller for carrying the developer and developing the latent image formed on the photosensitive drum 1, and 21 is a screw mixer for stirring the developer in the developing tank 5 to charge the toner. In this figure, as an example, a screw mixer is shown in which spiral protrusions are arranged on both a hollow cylinder and a rotating body provided inside the hollow cylinder and are rotated in opposite directions to stir the developer. It was. 22 is a toner concentration detection sensor for detecting the toner concentration of the developer in the developing tank 5, 23 is a toner conveying screw disposed in the toner conveying opening 10, 24 is a toner supply port of the toner container 9, 25 is toner, 26 Is a bearing on the developing tank 5 side of the screw 23 constituting the toner conveying opening 10, and 27 is a shaft rising from the bottom of the toner conveying opening 10 on the developing tank 5 side and also serves as a bearing for the screw mixer 21 to block the toner to be conveyed. A partition wall 28 that stops and overflows from the upper part to supply toner to the upper part of the screw mixer 21 , and 28 is a toner supply roller.
Toner entrance side of the transport opening path 10 - the opening 23a which extends in the container longitudinally disposed, that are provided in a position opening portion 23a facing the supply roller under side of the toner container 9.
[0023]
In the present invention, as shown in FIGS. 1 to 4, at least one toner container, for example, 9 and, for example, a developing tank 5 arranged in parallel with the container are connected by a toner conveying opening 10. The toner supply port to the developing tank 5 in the toner conveying opening 10 is a side surface of the screw mixer 21 on the side of the developing tank 5 facing the developing roller. A screw 23 is disposed in the toner conveyance opening 10, and the toner dropped from the toner supply port 24 of the toner container 9 is supplied to the screw mixer 21 of the developing tank 5 by the screw 23.
[0024]
That is, as described above, when the photosensitive drum 1 is made small, it is possible to arrange the developing tanks 3 to 6 for each color as apparent from FIG. 1, but all the toner containers 7 to 9 are placed in the developing tank 3. When the toner can be supplied from the top to the screw mixer 21 disposed in the developing tank or directly above the toner container 9, for example, the toner container 9 or the toner container 8 needs to be disposed further to the left or above in the drawing. In this case, it is natural that the electrophotographic apparatus itself needs to be large. In addition, in such a case, it is necessary to connect the toner container and the developing tank with toner conveying means, and it is necessary to prepare parts and control means for the parts, which is expensive and the electrophotographic apparatus itself is large. become.
[0025]
However, as mentioned above, at least one of the toner container, a toner transport opening path 10 between the example 9 and example the developing tank 5 disposed so as to be perpendicular to the screw mixer 21, the toner conveying opening path 10 By setting the toner supply port to the developing tank 5 to the side surface of the screw mixer 21 in the developing tank 5, that is, the side facing the developing roller 20 of the developing tank 5, the toner container 9 is installed immediately above the developing tank 5. As is apparent from FIG. 1, the developer tank 4 is not obstructed, and the developer tank 5 can be arranged in a state separated from the developer tank 5 on the left side of the drawing where there is a space. Therefore, the toner container 9 can be arranged without using a complicated toner conveyance opening path and control means and effectively using the space, and the electrophotographic apparatus itself can be made compact.
[0026]
The above is the developing device in the electrophotographic apparatus of the present invention. As shown in FIG. 2, the toner supply port to the developing tank 5 of the toner conveying opening 10 is the screw on the side facing the developing roller in the developing tank 5. a side surface of the mixer 21, as also shown in FIG. 4, the case of providing the bearing 26 of the screw 23 of the toner conveying opening slit 10 in the upper, the toner 25 conveyed by the screw 23 of the toner conveying opening slit 10, As shown in FIG. 2, there is a case where the toner enters the lower side of the screw mixer 21 and the toner remaining on the photosensitive drum 1 without being transferred to the developer in the developing tank 5 or the intermediate transfer body 11 may not be successfully stirred. Therefore, the second embodiment of the developing device in the electrophotographic apparatus of the present invention shown in FIG. 5 copes with such a situation.
[0027]
In the second embodiment shown in FIG. 5, the screw 23 rises from the bottom of the toner conveyance opening 10 between the toner supply port of the toner conveyance opening 10 to the developing tank 5 and the screw mixer 21. with a bearing, it blocked the toner being conveyed, is provided with a partition wall 27 as overflow means for exiting overflowing from the top. That is, as apparent from FIG. 5, the partition wall 27 as overflow means is under the axis of the upper neighborhood to Tachinobo wants to screw 23 of the screw mixer 21. The toner is conveyed by the screw 23 of the toner conveying opening slit 10, so that this overflow means once dam stopped by a partition wall 27 as indicated by arrows 25 in FIG. 6 when the toner some degree is accumulated, From the slits on both sides of the shaft of the screw 23 provided so as to be orthogonal to the screw mixer 21, the toner passes over the partition wall 27 and is supplied from the upper surface side of the screw mixer 21. For this reason, the toner is reliably agitated with the developer in the developing tank 5 and the toner remaining on the photosensitive drum 1 without being transferred to the intermediate transfer body 11, and developed with a developer having a low toner concentration without being sufficiently agitated. Will not cause image defects.
[0028]
The above is the developing device in the electrophotographic apparatus according to the present invention. The toner conveyance opening 10 described above is provided below the toner container 9 and is orthogonal to the screw mixer 21 of the corresponding developing tank 5. It is preferable to provide in the direction. That is, by providing a toner conveying opening slit 10 on the lower side of the toner container 9, the toner supply to the toner transport opening path 10 is just only need to drop the toner, also be provided in a direction perpendicular to the screw mixer 21 Thus, the toner container 9 and the screw mixer 21 can be connected at the shortest distance, and efficient toner conveyance can be performed. The screw 23 of the toner conveying opening path 10, the toner concentration detecting device 22 provided in the developing tank 5 may be the main operating when instructed toner supply, further, a screw mixer 21 provided in the developing tank 5 You may make it operate | move interlock | cooperated. If the screw 23 of the toner conveyance opening 10 is operated when the toner concentration detection device 22 instructs the toner supply, it is possible to eliminate the use of extra power and to operate in conjunction with the screw mixer 21. This eliminates the need for special drive means and control circuit for operating the screw 23 of the toner conveyance opening 10, thereby making it possible to provide an inexpensive electrophotographic apparatus.
[0029]
The operation of the electrophotographic apparatus having the developing device of the present invention will be briefly described below with reference to FIG. Now, when image data to be printed is sent, the photosensitive drum 1 is first charged by the charger 2, and an image corresponding to each color is exposed on the photosensitive drum 1 by an optical scanning unit (not shown). Then, a latent image is formed in a portion (exposed portion) where the light has been irradiated. Thereafter, development is performed by the developing device of a color corresponding to the exposed color image in the developing device, and a toner image is formed. This toner image is primarily transferred to the intermediate transfer member 11 side at the nip where the photosensitive drum 1 and the intermediate transfer member 11 are in contact with each other by the primary transfer bias applied between the photosensitive drum 1 and the intermediate transfer member 11. Thus, all other color toner images are primarily transferred to the intermediate transfer body 11. When the toner images of all colors are primarily transferred to the intermediate transfer body 11, the recording medium is conveyed from a paper feed cassette (not shown) to secondarily transfer the toner image on the intermediate transfer body 11, and this recording medium Is heated and pressed by a fixing device (not shown) to fix the toner image on the recording medium, and the paper is discharged.
[0030]
During this time, the toner concentration detection sensors 22 provided in the developing tanks 3 to 6 detect the concentration of the developer, and the illustration shows that the toner concentration in the developer decreases due to consumption of the toner by the image forming operation. not sends a signal to the control circuit of the electrophotographic apparatus, and instructs to supply the toner container or we toner corresponding to the developing tank 3-6 the toner density is reduced, the toner of the necessary amount from the corresponding toner containers developer tank To be supplied. In this supply, when an instruction is given to the toner container 9 corresponding to the developing tank 5 described above, for example, the toner replenishing roller 28 in the toner container 9 facing the toner supply port 24 rotates and the toner becomes the toner. The toner that has fallen into the conveyance opening 10 and dropped into the toner conveyance opening 10 is conveyed to the screw mixer 21 of the developing tank 5 by the screw 23, and the developer in the developing tank 5 and the intermediate transfer member 11 are conveyed by the screw mixer 21. The toner remaining on the photosensitive drum 1 without being transferred to the toner is reliably agitated.
[0031]
【The invention's effect】
According to the present invention described in claim 1 as described above, with the developing tank from the toner container, in the direction perpendicular to the screw mixer central portion of the developing tank, the toner conveying subscription-menu-type conveying means for supplying the toner By providing the toner conveyance opening path , it is not necessary to position the toner container in the upper part of the developing tank, and the toner container can be installed at a position separated from the developing tank by the toner conveyance opening path . In addition, a toner container is provided above the conventional screw mixer by damming the toner rising from the bottom to the developing tank side and providing a partition wall that overflows from the top and feeds the toner to the top of the screw mixer. As in the case, the supplied toner, the developer in the developing tank, and the toner remaining on the photosensitive drum without being transferred to the recording medium or the intermediate transfer member can be reliably mixed and stirred. As described above, since the toner container can be installed at a position away from the developing tank, it is possible to provide a developing device in an electrophotographic apparatus that effectively uses the space in the electrophotographic apparatus with a simple and inexpensive configuration.
[0032]
According to the second aspect of the present invention, since the partition wall is a developer tank side bearing of the toner transport screw shaft, there is no need to provide a special member as the partition wall, and the transported toner is stored in the developer tank. By supplying from the upper side of the toner, the supplied toner, the developer in the developing tank, and the toner remaining on the photosensitive drum without being transferred to the recording medium or the intermediate transfer body can be reliably mixed and stirred. same effect as the case of providing a toner container to a conventional screw mixers upper is obtained and there is no need to position the toner container above the developing tank as described above, also the toner container away from the developing tank position Therefore, it is possible to provide a developing device in an electrophotographic apparatus that does not cause defective development and that effectively uses the space in the electrophotographic apparatus with a simple and inexpensive configuration. Can.
[0033]
And according to the present invention described in claim 2, by providing the toner container on the upper side of the toner conveying screw, it is unnecessary to provide a special conveyance means to the toner conveying screw from the toner container, a simple, inexpensive structure It is possible to provide a developing device in an electrophotographic apparatus that effectively uses the space in the electrophotographic apparatus.
[0034]
According element to the present invention, by providing in a direction perpendicular to the toner conveyance screw and screw mixers, can connect the toner container and a screw mixer in the shortest distance, it is possible to perform efficient toner transport.
[0035]
According element to the present invention, the toner conveying screw toner concentration detecting device by to work when instructed toner supply may be an electrophotographic apparatus that does not use extra power.
[0036]
According to the element present invention, by operating the toner conveying screw in conjunction with a screw mixer, a special driving means or control circuit for operating the toner conveyance screw is not required, and correspondingly inexpensive electrophotographic apparatus can do.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an arrangement state of a developing tank and a toner container around a photosensitive drum in an embodiment of an electrophotographic apparatus provided with a developing device according to the present invention.
FIG. 2 is a detailed cross-sectional view of an embodiment of a developing device in the electrophotographic apparatus according to the present invention.
FIG. 3 is a perspective view of an embodiment of a developing tank and a toner conveyance opening constituting a developing device in the electrophotographic apparatus according to the present invention.
FIG. 4 is a perspective view of the toner conveyance opening from the developing tank side constituting the developing device in the electrophotographic apparatus according to the present invention.
FIG. 5 is a perspective view of another embodiment of a developing tank and a toner conveyance opening constituting a developing device in the electrophotographic apparatus according to the present invention.
FIG. 6 is a perspective view of the toner conveyance opening from the developing tank side constituting another embodiment of the developing device in the electrophotographic apparatus according to the present invention.
FIG. 7 is a diagram for explaining an arrangement of a toner container and a developing tank in a developing device in a conventional electrophotographic apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Photosensitive drum 5 Cyan (C) developing tank 9 Toner container 10 Toner conveyance opening 20 Developing roller 21 Screw mixer 22 Toner density detection sensor 23 Screw 24 Toner supply port 25 Toner flow 26 Bearing 27 Overflow means 28 Toner supply roller

Claims (2)

A developing roller which is disposed at a position opposed to the photosensitive light drum for developing the latent image, agitating it the parallel and developing roller, a developing tank screw mixers for transporting is accommodated, the In the developing device in the electrophotographic apparatus having a toner container disposed in parallel to the developing tank longitudinal direction on the developing tank back side opposite to the photosensitive drum through the developing tank ,
A conveyance opening path connecting the toner container and the developing tank is formed from the central position in the screw mixer axial direction toward the toner container, and the toner conveyance screw is accommodated in the conveyance opening path, and the toner conveyance the outlet end of the screw, dammed toner conveyed rises from the bottom portion to the developing tank side of the transport opening path, that the partition wall to send the toner by overflow from the top to the top of the screw mixer is provided A developing device in an electrophotographic apparatus. 2. An electrophotographic apparatus according to claim 1 , wherein an opening extending in the longitudinal direction of the toner container is provided on the entrance side of the conveying opening, and the opening is provided at a facing position below the toner container replenishing portion. Development device.

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