JP2005173295A - Image forming apparatus, exchange unit, and developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the efficiency of maintenance work of a filter for catching and storing toner by stably reducing toner scatter despite lapse of time. <P>SOLUTION: The image forming apparatus is equipped with: developing sections 23Y, 23M, 23C, and 23BK which are subjected to maintenance at a predetermined cycle; and an exchange unit 75 which is provided with a filter 76 for catching and storing the toner and which is exchanged and installed in the main part 1 of the image forming apparatus at a cycle shorter than the maintenance cycles of the developing sections 23Y, 23M, 23C, and 23BK. The gas in the developing sections 23Y, 23M, 23C, and 23BK flows into the exchange unit 75 through a gas transport passage 71 and flows out to the outside of the exchange unit 75 through the filter 76. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile, or a multifunction machine thereof, and an exchange unit and a developing device installed therein.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a printer, many techniques for reducing toner scattering in a developing unit have been disclosed as the apparatus becomes more reliable and faster.

  For example, Patent Document 1 discloses a technique in which a duct (toner carrier covering member) is provided around a developing unit (developing unit) and the air in the duct is forcibly sucked by a suction fan. According to this technique, the toner scattered from the developing unit moves in the duct to the suction fan side. The scattered toner is collected by a toner filter installed in the vicinity of the suction fan.

Patent Document 2 discloses a technique in which an exhaust duct for reducing internal pressure in a plurality of developing units (developing devices) is provided, and a waste developer container provided with a toner filter is connected to the exhaust duct. ing. According to this technique, a suction air flow is generated in the plurality of developing units, and the toner floating in the developing unit moves in the exhaust duct without being scattered from the developing unit. The toner moving in the exhaust duct is collected by a toner filter installed in the waste developer container.
Here, in the waste developer container, the two-component developer that has been used in the developing unit and has reached the end of its life is collected by automatic replacement and then stored as a waste developer. As the waste developer container is replaced with a new one (empty one), the toner filter is also replaced with a new one.

JP 2002-278268 A JP 2003-15420 A

  In the conventional image forming apparatus described above, it has been difficult to stably reduce toner scattering over time. In particular, in recent image forming apparatuses, the particle size of the toner is reduced for the purpose of improving the image quality, and the configuration is disadvantageous against toner scattering. .

  Specifically, in the technique of Patent Document 1 described above, when the toner filter is clogged with toner over time, the suction force of the scattered toner by the suction fan decreases. Therefore, it is necessary to periodically perform maintenance (replacement with a new filter, cleaning for removing clogging, etc.) on the toner filter.

However, in the technique of Patent Document 1, when the maintenance of the toner filter is performed, since the duct (toner carrier covering member) in which the toner filter is installed and the developing unit are integrated, these are formed as an image. It is necessary to remove the device from the main body and perform maintenance, and the maintenance workability is poor.
In a color image forming apparatus having a plurality of developing units, ducts having toner filters are installed as many as the number of developing units. Therefore, when the maintenance of the toner filter is performed, the burden on the maintenance worker is increased by the number of developing units.

  On the other hand, in the technique disclosed in Patent Document 2, the toner filter is replaced in a maintenance cycle in which the waste developer container is replaced with a new one. Further, since only one waste developer container provided with a toner filter is separately provided for a plurality of developing units, the burden on the maintenance worker is small and the workability is high.

However, in the technique of Patent Document 2, the replacement cycle of the waste developer container corresponds to the life of the developer and is relatively long. Therefore, there is a possibility that the toner filter is clogged before the waste developer container is replaced, and the toner in the developing portion cannot be decompressed and toner scattering occurs.
Particularly in recent image forming apparatuses, for the purpose of reducing the running cost, the life of the carrier in the developer is prolonged, and the developer replacement cycle is lengthened. Therefore, when the cycle of maintenance of the developing unit (automatic replacement of developer) and the replacement cycle of the toner filter are synchronized, the above-described problem is further increased.

  The present invention has been made to solve the above-described problems. An image forming apparatus in which toner scattering is stably reduced over time, and maintenance work for a filter that collects toner is high. To provide a unit and a developing device.

  The image forming apparatus according to the first aspect of the present invention is formed so as to develop the latent image formed on the image carrier and to maintain the developing unit maintained in a predetermined cycle and to collect the toner. A replacement unit that is replaced and installed in the image forming apparatus main body in a cycle shorter than a maintenance cycle of the developing unit, a gas transport path that communicates between the developing unit and the replacement unit, And the gas in the developing unit is configured to flow into the replacement unit through the gas transport path and to flow out of the replacement unit through the filter.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect of the present invention, the gas transport path includes an air pump.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the gas conveyance path includes a suction fan.

  According to a fourth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to third aspects, wherein the replacement unit discards the untransferred toner collected from the image carrier. This is a waste toner container that accommodates toner.

  An image forming apparatus according to a fifth aspect of the present invention is the image forming apparatus according to any one of the first to fourth aspects, wherein the replacement unit includes a charging unit that charges the image carrier and the image. A process cartridge in which at least one of the cleaning unit for cleaning the surface of the carrier and the image carrier is integrated.

  According to a sixth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to fifth aspects, wherein the toner container that contains the toner to be supplied to the developing unit is supplied to the replacement unit. It is what.

  An image forming apparatus according to a seventh aspect of the present invention is the image forming apparatus according to any one of the first to sixth aspects, wherein the replacement unit includes a wall portion that partitions the space into which the gas flows. It is a thing.

  An image forming apparatus according to an eighth aspect of the present invention is the image forming apparatus according to any one of the first to seventh aspects, wherein the developing unit includes an opening communicating with the gas conveyance path, When the developing unit is in a new state, the opening is sealed with a sealing member.

  An image forming apparatus according to a ninth aspect of the present invention is the image forming apparatus according to the eighth aspect, wherein the developing section includes a developer container that contains a two-component developer to be supplied into the developing section. The opening is provided in the developer container.

  An image forming apparatus according to a tenth aspect of the present invention is the image forming apparatus according to any one of the first to ninth aspects, comprising a plurality of the developing sections.

  An image forming apparatus according to an eleventh aspect of the present invention is the image forming apparatus according to the tenth aspect, wherein the replacement unit replaces the black toner among the plurality of toner containers that respectively supply toner to the plurality of developing units. This is a toner container to be accommodated.

  An image forming apparatus according to a twelfth aspect of the present invention is the image forming apparatus according to the tenth or eleventh aspect, wherein the replacement unit includes a plurality of toner containers that respectively supply toner to the plurality of developing units. Among them, the toner container having the largest internal volume is used.

  According to a thirteenth aspect of the present invention, an exchange unit is an exchange unit that is installed in a replaceable manner with respect to the main body of the image forming apparatus, and includes a filter formed so as to be able to collect toner. The gas in the developing unit is configured to be connectable to a gas transport path communicating with a developing unit that develops a latent image formed on the carrier, and is exchanged in a cycle shorter than the maintenance cycle of the developing unit. Is configured to flow into the inside through the gas transport path and out to the outside through the filter.

  According to a fourteenth aspect of the present invention, there is provided an exchange unit according to the thirteenth aspect of the present invention, wherein the replacement unit is a waste toner container for storing untransferred toner recovered from the image carrier as waste toner.

  According to a fifteenth aspect of the present invention, there is provided an exchange unit according to the thirteenth or fourteenth aspect, wherein a charging unit that charges the image carrier and a cleaning unit that cleans the image carrier are provided. At least one of them and the image carrier are integrated into a process cartridge.

  According to a sixteenth aspect of the present invention, in the invention according to any one of the thirteenth to fifteenth aspects, the replacement unit is a toner container in which toner to be supplied to the developing section is accommodated.

  An exchange unit according to the invention described in claim 17 is the invention according to any one of claims 13 to 16, further comprising a wall portion that partitions the space into which the gas flows.

  The developing device according to claim 18 of the present invention is a developing device that develops a latent image formed on an image carrier and is maintained in a predetermined cycle, and can collect toner. It is configured to be connectable to a gas transport path communicating with an exchange unit including a filter formed on the image forming apparatus, and is maintained in a cycle longer than the exchange cycle of the exchange unit in the image forming apparatus main body. It is configured to flow into the replacement unit via the gas transport path and to flow out of the replacement unit via the filter.

  In addition, the developing device according to the nineteenth aspect of the present invention is the developing device according to the eighteenth aspect of the present invention, further comprising an opening that communicates with the gas conveyance path, and sealing the opening when it is in a new state. It is sealed with a member.

  According to a twentieth aspect of the present invention, there is provided a developing device according to the nineteenth aspect of the present invention, further comprising a developer container that contains a two-component developer supplied into the device, wherein the opening portion is the developer. It is provided in the container.

  A developing device according to a twenty-first aspect of the present invention is the developing device according to any one of the eighteenth to twentieth aspects, wherein the image carrier, a charging unit that charges the image carrier, It is integrated with at least one of a transfer unit that transfers a toner image formed on the image carrier to a transfer material, a cleaning unit that cleans the image carrier, and a toner container that contains toner. It is a thing.

  In the present invention, a filter for collecting toner is installed in an exchange unit that is exchanged in an exchange cycle shorter than the maintenance cycle of the developing unit. As a result, the image forming apparatus, the replacement unit, and the developing apparatus that can stably reduce the toner scattering over time and have high maintenance workability regardless of the toner particle size reduction or the developer life extension. Can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

Embodiment 1 FIG.
A first embodiment of the present invention will be described in detail with reference to FIGS.
First, the configuration and operation of the entire image forming apparatus will be described with reference to FIG.
In FIG. 1, 1 is a main body of a color printer as an image forming apparatus, 2 is a writing unit that emits laser light based on image information, and 20Y, 20M, 20C, and 20BK are colors (yellow, magenta, cyan, and black). The corresponding process cartridge 21 is a photosensitive drum as an image carrier housed in each of the process cartridges 20Y, 20M, 20C, and 20BK, 22 is a charging unit that charges the photosensitive drum 21, 23Y, 23M, 23C, 23BK is a developing unit (developing device) for developing the electrostatic latent image formed on the photosensitive drum 21, 24 is a transfer bias roller for transferring the toner image formed on the photosensitive drum 21 to the intermediate transfer belt 27, Reference numeral 25 denotes a cleaning unit that collects untransferred toner on the photosensitive drum 21.

  In addition, 27 is an intermediate transfer belt as an image carrier on which toner images of respective colors are transferred in an overlapping manner, and 28 is a second transfer bias roller for transferring the toner image formed on the intermediate transfer belt 27 to a transfer material P, 29 is an intermediate transfer belt cleaning unit that collects untransferred toner on the intermediate transfer belt 27, 30 is a transfer belt that conveys a transfer material P onto which four color toner images are transferred, 32Y, 32M, 32C, and 32BK. Is a toner replenishing unit that replenishes each color toner to each developing unit 23Y, 23M, 23C, and 23BK, 61 is a paper feeding unit that accommodates a transfer material P such as transfer paper, and 66 is an unfixed image on the transfer material P A fixing unit for fixing an image, 70 is a conveyance pipe for guiding the collected toner to the waste toner container 75, 71 is a tube as a gas conveyance path, and 75 is an exchange unit for accommodating the collected toner as waste toner Waste toner container 76 is a filter that is formed so as to collect the toner (toner filter), 77 denotes a pump installed in the gas transport path of the tube 71.

Here, each of the process cartridges 20Y, 20M, 20C, and 20BK is obtained by integrating the photosensitive drum 21, the charging unit 22, and the cleaning unit 25, respectively. The process cartridges 20Y, 20M, 20C, and 20BK are replaced with a predetermined maintenance cycle (replacement cycle) with respect to the apparatus main body 1 based on the lifetime of the constituent members. Similarly, the developing units 23Y, 23M, 23C, and 23BK are also replaced with a predetermined maintenance cycle (replacement cycle) with respect to the apparatus main body 1 based on the lifetime of the developer.
Image formation of each color (yellow, magenta, cyan, black) is performed on the photosensitive drum 21 in each of the process cartridges 20Y, 20M, 20C, and 20BK.

Hereinafter, an operation during normal color image formation in the image forming apparatus will be described.
Each of the four photosensitive drums 21 rotates counterclockwise in FIG. First, the surface of the photosensitive drum 21 is uniformly charged at a position facing the charging unit 22 (a charging process). Thereafter, the surface of the charged photosensitive drum 21 reaches the irradiation position of each laser beam.

  On the other hand, in the writing unit 2, laser light corresponding to the image signal is emitted from the light source corresponding to each color. The laser light is incident on the polygon mirror 3 and reflected, and then passes through the lenses 4 and 5. The laser light after passing through the lenses 4 and 5 passes through different optical paths for each color component of yellow, magenta, cyan, and black (this is an exposure process).

The laser beam corresponding to the yellow component is reflected by the mirrors 6 to 8 and then irradiated onto the surface of the photosensitive drum 21 of the first process cartridge 20Y from the right side of the drawing. At this time, the yellow component laser light is scanned in the rotation axis direction (main scanning direction) of the photosensitive drum 21 by the polygon mirror 3 that rotates at high speed. Thus, an electrostatic latent image of a yellow component is formed on the photosensitive drum 21 charged by the charging unit 22.
Similarly, the magenta component laser light is reflected by the mirrors 9 to 11 and then irradiated to the surface of the photosensitive drum 21 of the second process cartridge 20M from the right side of the paper, thereby forming an electrostatic latent image of the magenta component. The The cyan component laser light is reflected by the mirrors 12 to 14 and then irradiated to the surface of the photosensitive drum 12 of the third process cartridge 20C from the right side of the paper, thereby forming an electrostatic latent image of the cyan component. The black component laser light is reflected by the mirror 15 and then is irradiated onto the surface of the photosensitive drum 21 of the fourth process cartridge 20BK from the right side of the drawing to form a black component electrostatic latent image.

Thereafter, the surface of the photosensitive drum 21 on which the electrostatic latent images of the respective colors are formed further rotates and reaches the positions facing the developing units 23Y, 23M, 23C, and 23BK, respectively. Then, each color toner is supplied onto the photosensitive drum 21 from the developing units 23Y, 23M, 23C, and 23BK, and the latent image on the photosensitive drum 21 is developed (this is a developing step).
Thereafter, the surface of the photosensitive drum 21 after the development process reaches a position facing the intermediate transfer belt 27. Here, the transfer bias roller 24 is installed at each facing position so as to contact the inner peripheral surface of the intermediate transfer belt 27. Then, the image of each color formed on the photosensitive drum 21 is sequentially transferred onto the intermediate transfer belt 27 at the position of the transfer bias roller 24 (first transfer step).

Then, the surface of the photosensitive drum 21 after the first transfer process reaches a position facing the cleaning unit 25. The untransferred toner remaining on the photosensitive drum 21 is collected by the cleaning unit 25 (this is a cleaning process).
Note that the untransferred toner collected by the cleaning unit 25 passes through a transport pipe 70 (a dashed line in the figure) in which a transport screw is inserted and is transported to the waste toner container 75.
Thereafter, the surface of the photosensitive drum 21 passes through a static elimination unit (not shown), and a series of image forming processes on the photosensitive drum 21 is completed.

On the other hand, the surface of the intermediate transfer belt 27 on which the images of the respective colors on the photosensitive drum 21 are transferred in an overlapping manner travels in the direction of the arrow in the drawing and reaches the position of the second transfer bias roller 28. Then, the full color image on the intermediate transfer belt 27 is secondarily transferred onto the transfer material P at the position of the second transfer bias roller 28 (secondary transfer step).
Thereafter, the surface of the intermediate transfer belt 27 reaches the position of the intermediate transfer belt cleaning unit 29. Then, the untransferred toner on the intermediate transfer belt 27 is collected by the intermediate transfer belt cleaning unit 29, and a series of transfer processes on the intermediate transfer belt 27 is completed.
The untransferred toner collected by the intermediate transfer belt cleaning unit 29 passes through the conveyance tube 70 and is conveyed to the waste toner container 75 in the same manner as the toner collected by the cleaning unit 25.

Here, the transfer material P at the position of the second transfer bias roller 28 is transported from the paper feeding unit 61 via the transport guide 63, the registration roller 64, and the like.
Specifically, the transfer paper P fed by the paper feed roller 62 from the paper feed unit 61 that stores the transfer material P is guided to the registration roller 64 after passing through the conveyance guide 63. The material P to be transferred that has reached the registration roller 64 is conveyed toward the position of the second transfer bias roller 28 in synchronization with the toner image on the intermediate transfer belt 27.

Thereafter, the transfer material P onto which the full color image has been transferred is guided to the fixing unit 66 by the transfer belt 30. In the fixing unit 66, the color image is fixed on the transfer material P at the nip between the heating roller 67 and the pressure roller 68.
Then, the transfer material P after the fixing process is discharged as an output image outside the apparatus main body 1 by the paper discharge roller 69, and a series of image forming processes is completed.

Next, a characteristic configuration / operation in the first embodiment will be described.
As shown in FIG. 1, a tube 71 (shown by a broken line in the drawing) is connected between each developing unit 23Y, 23M, 23C, 23BK and the waste toner container 75. Further, an air pump 77 is connected in the gas conveyance path by the tube 71. Here, the air pump 77 is installed so that the intake side becomes the developing units 23Y, 23M, 23C, and 23BK, and the exhaust side becomes the waste toner container 75.

With the configuration described above, the gas (air) in each of the developing units 23Y, 23M, 23C, and 23BK moves in the tube 71 and is transported to the waste toner container 75 (moving in the direction of the arrow). As a result, a suction air flow is generated in each of the developing units 23Y, 23M, 23C, and 23BK, and toner scattering from the developing unit is suppressed.
That is, the developing units 23Y, 23M, 23C, and 23BK have an opening that exposes a part of the peripheral surface of the developing roller at a position facing the photosensitive drum 21. Then, the air in the developing units 23Y, 23M, 23C, and 23BK is sucked in through the tube 71, so that the outside air is sucked from the opening facing the photosensitive drum 21. As a result, the generation of an airflow in which toner scatters from the opening of the developing unit to the outside is limited.

  On the other hand, the gas that has flowed into the waste toner container 75 from the developing units 23Y, 23M, 23C, and 23BK flows out of the waste toner container 75 through the filter 76. Here, since the toner is powder, toner particles are mixed in the gas flowing into the waste toner container 75, but the toner in the gas is collected by the filter 76. Thus, the gas discharged from the waste toner container 75 does not contain toner, and the inside of the apparatus main body 1 can be prevented from being contaminated with toner.

In the first embodiment, the gas discharged from the waste toner container 75 is discharged into the apparatus main body 1, but may be discharged out of the apparatus main body 1.
Further, in the waste toner container 75, it is preferable that the space into which the gas from the developing unit flows and the space in which the waste toner is stored be partitioned by a wall portion. Accordingly, it is possible to prevent the waste toner stored in the waste toner container 75 from floating in the container 75 by the inflowing gas and shortening the life of the filter 76.

  Here, in the first embodiment, the waste toner container 75 as an exchange unit is detachably installed on the apparatus main body 1. Then, at every predetermined replacement cycle, the existing waste toner container 75 is taken out from the apparatus main body 1, and a new waste toner container 75 is attached to the apparatus main body 1 instead. At this time, as the waste toner container 75 is replaced, the filter 76 is also replaced with a new one. The tube 71 and the transport tube 70 are configured to be brought into contact with and separated from each other in conjunction with the attaching / detaching operation of the waste toner container 75.

The replacement cycle of the waste toner container 75 is set shorter than any replacement cycle (maintenance cycle) of the plurality of developing units 23Y, 23M, 23C, and 23BK.
Specifically, in the first embodiment, the replacement cycle of each of the developing units 23Y, 23M, 23C, and 23BK corresponds to the life of the developer, which is 100,000 sheets (in terms of the number of output images of A4 size output images). Yes). On the other hand, the replacement cycle of the waste toner container 75 is set to 30,000 to 50,000 sheets. Accordingly, the filter 76 is exchanged two to three times without removing the developing units 23Y, 23M, 23C, and 23BK from the apparatus main body 1.

Thus, before the filter 76 installed in the waste toner container 75 is clogged, the waste toner container 75 is replaced with a new one together with the filter 76. Accordingly, a suction airflow is stably generated over time in the developing units 23Y, 23M, 23C, and 23BK, and the effect of suppressing toner scattering is maintained for a long time.
Note that control based on the number of output images can be performed so that the waste toner container 75 is not replaced beyond a predetermined replacement cycle. For example, when the predetermined number of output sheets is reached after the waste toner container 75 is replaced, it can be controlled so that image formation cannot be forcibly performed until the replacement maintenance is completed.

  Further, in the first embodiment, the filter replacement operation for suppressing toner scattering does not perform filter replacement for each of the plurality of developing units 23Y, 23M, 23C, and 23BK. It is performed at the same time by exchanging the container 75. Therefore, in addition to the above-described effects, there is an effect that the burden on the maintenance worker can be reduced.

Next, the image forming unit of the image forming apparatus will be described in detail with reference to FIGS. FIG. 2 is a cross-sectional view showing the image forming unit, and FIG. 3 is a cross-sectional view taken along the line AA showing the developing unit.
The four image forming units installed in the apparatus main body 1 have substantially the same structure except that the color of the toner T to be stored is different. Therefore, alphabets (Y, (M, C, BK) are shown.

  As shown in FIG. 2, the process cartridge 20 mainly contains a photosensitive drum 21 as an image carrier, a charging unit 22, and a cleaning unit 25 integrally in a case 26. The cleaning unit 25 is provided with a cleaning blade 25 a and a cleaning roller 25 b that are in contact with the photosensitive drum 21. A transport pipe 70 is connected to the opening 25 c of the cleaning unit 25.

The developing unit (developing device) 23 mainly faces the first conveying screw 23b via the developing roller 23a facing the photosensitive drum 21, the first conveying screw 23b facing the developing roller 23a, and the partition member 23e. The second conveying screw 23c and a doctor blade 23d facing the developing roller 23a are configured. In the developing unit 23, a two-component developer composed of carrier C and toner T is accommodated. The developing roller 23a includes a magnet that is fixed inside and forms a magnetic field on the circumferential surface of the roller, and a sleeve that rotates around the magnet.
Further, a tube 71 as a gas transport path is connected to the opening 23 g of the developing unit 23. Further, the toner supply unit 32 is engaged with the supply port 23 f of the developing unit 23.

The above-described image forming process will be described in more detail with a focus on the developing process.
The developing roller 23a rotates in the direction of the arrow in FIG. As shown in FIG. 3, the developers T and C in the developing unit 23 are driven by the rotational drive of the first transport screw 23b and the second transport screw 23c disposed so as to interpose the partition member 23e therebetween. It circulates in the longitudinal direction while being agitated and mixed with the toner T replenished from the replenishing portion 32 through the replenishing port 23f (circulation in the direction of the arrow in FIG. 3). The toner T that is frictionally charged and adsorbed on the carrier C is supplied to the developing roller 23a together with the carrier C by the first conveying screw 23b, and the developers T and C are carried on the developing roller 23a.

Thereafter, the developers T and C carried on the developing roller 23a are adjusted to an appropriate amount at the position of the doctor blade 23d, and then reach a position facing the photosensitive drum 21 (developing area). At the opposite position, the toner T in the developer adheres to the electrostatic latent image formed on the surface of the photosensitive drum 21. Specifically, the toner T is latently developed by an electric field (development electric field) formed by a potential difference (development potential) between the latent image potential of the image portion irradiated with the laser beam L and the development bias applied to the development roller 23a. Adhere to the image.
Thereafter, most of the toner T adhering to the photosensitive drum 21 is transferred onto the transfer material P. Then, the toner T remaining on the photosensitive drum 21 is collected in the cleaning unit 25 by the cleaning blade 25a and the cleaning roller 25b that are in contact with the photosensitive drum 21.

  Here, the toner replenishing section 32 provided in the apparatus main body includes a toner bottle 33 configured to be replaceable, a toner hopper section 34 that holds and rotates the toner bottle 33 and replenishes the developing section 23 with fresh toner T. , Is composed of. The toner bottle 33 contains toner T (any one of yellow, magenta, cyan, and black). In addition, a spiral protrusion is formed on the inner peripheral surface of the toner bottle 33.

  The toner T in the toner bottle 33 is appropriately replenished into the developing unit 23 from the replenishing port 23f as the toner T in the developing unit 23 is consumed. The consumption of the toner T in the developing unit 23 is indirectly detected by the reflective photosensor 28 facing the photosensitive drum 21. The replenishing port 23f is provided at one end in the longitudinal direction (the vertical direction in FIG. 3) of the second transport screw 23c and above the second transport screw 23c.

  2 and 3, the opening 23g of the developing unit 23 is provided above the developing unit 23 and at a position not buried in the developers T and C. And the tube 71 is connected with respect to this opening part 23g so that gas may not leak. As described with reference to FIG. 1, the gas in the developing unit 23 is sucked through the tube 71 and toner scattering from the developing unit 23 is suppressed.

  As described above, in the image forming apparatus configured as in the first embodiment, toner is collected in the waste toner container 75 that is replaced in a replacement cycle shorter than the maintenance cycle of the developing unit 23. A filter 76 is installed. As a result, the toner scattering can be stably reduced over time and the maintenance workability can be improved regardless of the reduction in the particle size of the toner T and the extension of the life of the developers T and C.

Embodiment 2. FIG.
The second embodiment of the present invention will be described in detail with reference to FIG.
FIG. 4 is a configuration diagram illustrating an image forming unit of the image forming apparatus according to the second embodiment, and corresponds to FIG. 2 of the first embodiment. In the second embodiment, the process cartridge 20 is used in place of the waste toner container 75 as an exchange unit in which a filter is installed, and a suction fan 78 is installed in the gas conveyance path instead of the air pump 77. This is different from the first embodiment.

As shown in FIG. 4, a plurality of developing units (developing devices) 23 installed in the apparatus main body are each provided with a tube 71 as a gas transport path between the corresponding process cartridge 20.
A wall for partitioning the space into which the gas conveyed from the developing unit 23 flows into the process cartridge 20 from other spaces (spaces for holding the photosensitive drum 21, the charging unit 22, and the cleaning unit 25). A portion 26a is provided. A filter 76 is installed in the opening for discharging the gas flowing into the space out of the process cartridge 20.
Further, a suction fan 78 is installed near the filter 76 in the apparatus main body 1.

With the configuration described above, the gas in the developing unit 23 moves in the tube 71 and is transported into the process cartridge 20 (moving in the direction of the broken line arrow). As a result, a suction air flow is generated in the developing unit 23 and toner scattering from the developing unit 23 is suppressed.
On the other hand, the gas that has flowed into the process cartridge 20 from the developing unit 23 flows out of the process cartridge 20 after the toner mixed by the filter 76 is collected.

  Here, in the second embodiment, the process cartridge 20 as an exchange unit is detachably installed on the apparatus main body 1. Then, at every predetermined replacement cycle, the existing process cartridge 20 is taken out from the apparatus main body 1 and a new process cartridge 20 is mounted on the apparatus main body 1 instead. At this time, as the process cartridge 20 is replaced, the filter 76 is also replaced with a new one.

Note that the replacement cycle of the process cartridge 20 is set shorter than the replacement cycle of the developing unit 23.
Specifically, in the second embodiment, the replacement cycle of the developing unit 23 is set to 100,000 sheets corresponding to the life of the developer. On the other hand, the replacement cycle of the process cartridge 20 is set to 50,000 to 70,000 sheets.

  As described above, in the image forming apparatus configured as in the second embodiment, the filter that collects toner in the process cartridge 20 that is replaced in a replacement cycle shorter than the maintenance cycle of the developing unit 23. 76 is installed. Accordingly, toner scattering can be stably reduced over time, and maintenance workability can be improved.

Embodiment 3 FIG.
A third embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 5 is a configuration diagram illustrating an image forming unit of the image forming apparatus according to the third embodiment, and corresponds to FIG. 2 of the first embodiment. 6 is a cross-sectional view taken along the line BB in the toner bottle of FIG. In the third embodiment, a toner bottle 33 is used instead of a waste toner container as an exchange unit in which a filter is installed, and an air pump is not installed in the gas conveyance path. 1 and different.

As shown in FIG. 5, each of the plurality of developing units 23 installed in the apparatus main body is provided with a tube 71 serving as a gas transport path between the toner bottle 33 serving as a corresponding toner container.
Referring to FIG. 6, the toner bottle 33 contains toner T containing toner T for replenishing the gas inflow portion 36 as a space into which the gas conveyed from the developing portion 23 flows into the developing portion 23. A wall portion 33 b for partitioning from the accommodating portion 37 is provided. A filter 76 is installed in the opening for discharging the gas flowing into the gas inflow portion 36 out of the toner bottle 33.

Here, in each of the embodiments described above, the toner bottle 33 itself rotates, and thus the toner is discharged out of the bottle from a discharge port (not shown).
On the other hand, in the third embodiment, the toner bottle 33 itself does not rotate, and the toner T is discharged from the discharge port to the outside of the bottle by the rotation drive of the conveying coil 38 installed in the bottle (in FIG. 6). Is the movement in the direction of the solid arrow. Thereby, the tube 71 can be prevented from being caught by the rotation of the toner bottle 33. When the tube 71 is inserted not at the peripheral surface of the toner bottle 33 but at the center of the end surface, the tube 71 is not caught even if the toner bottle 33 is driven to rotate.

With the configuration described above, the gas in the developing section 23 moves in the tube 71 and flows into the gas inflow section 36 of the toner bottle 33 from the inflow port 33a (movement in the direction of the broken line arrow). As a result, a suction air flow is generated in the developing unit 23 and toner scattering from the developing unit 23 is suppressed.
Here, in the third embodiment, unlike the above-described embodiments, since the air pump and the suction fan are not installed in the gas conveyance path, the gas in the developing unit 23 is forcibly sucked. Can not. Even in this case, when the pressure in the developing unit 23 increases and toner scattering is likely to occur, the pressure in the developing unit 23 is reduced by the balance with the pressure in the gas inflow portion 36 of the toner bottle 33. (Equilibrated state) As a result, a suction air flow is generated in the developing unit 23.

  On the other hand, the gas that has flowed into the gas inflow portion 36 of the toner bottle 33 from the developing portion 23 flows out of the toner bottle 33 in a state where the toner mixed by the filter 76 is collected.

  Here, in the third embodiment, the toner bottle 33 as an exchange unit is detachably installed on the apparatus main body 1. Then, every time the toner T in the toner storage unit 37 is consumed and becomes empty, the existing toner bottle 33 is taken out from the apparatus main body 1 and a new toner bottle 33 is attached to the apparatus main body 1 instead. The At this time, as the toner bottle 33 is replaced, the filter 76 is also replaced with a new one.

The replacement cycle of the toner bottle 33 is set shorter than the replacement cycle of the developing unit 23.
Specifically, in the third embodiment, the replacement cycle of the developing unit 23 is set to 100,000 sheets corresponding to the life of the developer. On the other hand, the replacement cycle of the toner bottle 33 is set to approximately 1 to 20,000 sheets although it varies depending on the image ratio of the output image.

  As described above, in the image forming apparatus configured as in the third embodiment, the filter that collects toner in the toner bottle 33 that is replaced in a replacement cycle shorter than the maintenance cycle of the developing unit 23. 76 is installed. Accordingly, toner scattering can be stably reduced over time, and maintenance workability can be improved.

Embodiment 4 FIG.
A fourth embodiment of the present invention will be described in detail with reference to FIG.
FIG. 7 is a configuration diagram illustrating the image forming apparatus according to the fourth embodiment, and corresponds to FIG. 1 of the first embodiment. The fourth embodiment is different from the third embodiment in that one of a plurality of toner bottles installed in the image forming apparatus main body is used as an exchange unit including a filter.

As shown in FIG. 7, the plurality of developing units 23Y, 23M, 23C, and 23BK are each a tube 71 serving as a gas transport path between the developing bottles 23Y, 23M, 23C, and 23BK. Is installed.
Here, in the fourth embodiment, only the toner bottle 33 storing the black toner has the same form as the toner bottle 33 described in the third embodiment. That is, the toner bottle 33 for black toner is provided with a gas inflow portion 36 and a filter 76.

With the configuration described above, the gas in the developing unit 23 moves in the tube 71 and flows into the toner bottle 33 installed in the toner replenishing unit 32BK for black toner (moving in the direction of the broken arrow). .) As a result, a suction air flow is generated in the developing unit 23 and toner scattering from the developing unit 23 is suppressed.
On the other hand, the gas flowing into the toner bottle 33 from the developing unit 23 flows out of the toner bottle 33 in a state where the toner mixed by the filter 76 is collected.

  The toner bottle 33 for black toner is configured to have a larger internal volume than other toner bottles (the toner bottles 33 installed in the other toner replenishing units 32Y, 32M, and 32C). Has been. As a result, a relatively large filter 76 installed in the toner bottle 33 can be used, so that the life of the filter 76 can be extended. Furthermore, since the opening in which the filter 76 is installed can be enlarged and the amount of gas flowing out of the toner bottle 33 can be increased, the effect of reducing the pressure in the developing unit 23 is also increased.

  Further, in a normal image forming apparatus, the toner bottle 33 for black toner consumes a larger amount of toner than the toner bottles 33 for other colors, so that the replacement cycle is shortened. Therefore, the replacement cycle of the filter 76 can be shortened regardless of the size of the internal volume.

  As described above, in the image forming apparatus configured as in the fourth embodiment, the filter that collects toner in the toner bottle 33 that is replaced in a replacement cycle shorter than the maintenance cycle of the developing unit 23. 76 is installed. Accordingly, toner scattering can be stably reduced over time, and maintenance workability can be improved.

Embodiment 5 FIG.
8 and 9, the fifth embodiment of the present invention will be described in detail.
FIG. 8 is a configuration diagram illustrating the image forming apparatus according to the fifth embodiment, and corresponds to FIG. 2 of the first embodiment. FIG. 9 is a cross-sectional view taken along the line CC in the developing unit of FIG. The fifth embodiment is different from the above-described embodiments in that a tube 71 communicating with the developing unit is connected to the developer container 80.

As shown in FIGS. 8 and 9, a developer container 80 is installed above the developing unit 23.
Here, in the new developing section (developing device) 23, the developers T and C are stored in advance in the developer storage section 80a of the developer container 80 (preset). Further, a sealing member 81 such as a sealing material is attached to the bottom of the developer container 80.

  Referring to FIG. 9, the developer container 80 is formed with a gas outflow portion 80b that does not contain a developer, separated from the wall surface 80c, in addition to the developer accommodating portion 80a described above. The gas outflow part 80b is provided with an opening 23g. The above-described sealing member 81 is stuck from the bottom of the developer accommodating portion 80a to the bottom of the wall surface 80c and the gas outflow portion 80b. That is, the sealing member 81 is configured so that the developers T and C in the developer accommodating portion 80a do not leak from the opening 23g.

  When the new developing unit 23 is attached to the image forming apparatus main body 1, the sealing member 81 is removed from the developing unit 23 by the operator (operation in the direction of the broken line arrow in FIG. 9). As a result, the developers T and C are supplied into the developing section 23, and the opening 23g of the gas outflow section 80b is opened. Further, the tube 71 is connected to the opening 23g of the new developing unit 23, so that gas can flow out from the opening 23g.

Note that the connection between the opening 23 g of the developing unit 23 and the tube 71 is performed in conjunction with the operation of mounting the developing unit 23 on the apparatus main body 1. That is, the developing unit 23 moves from the left side to the right side in FIG. The tube 71 is engaged with the opening 23g by the movement of the developing unit 23.
Further, the developer container 80 after removing the sealing member 81 functions as a case of the developing unit 23 as it is.

  In the fifth embodiment, the opening 23g in the new developing unit 23 is indirectly sealed by the sealing member 81 to prevent the leakage of the developer during transportation of the developing unit 23 or the like. On the other hand, it is also possible to prevent leakage of the developer by sticking a sealing member directly to the opening 23g in the new developing unit 23.

  With the configuration described above, the gas in the developing unit 23 moves through the tube 71 from the opening 23g of the gas outflow portion 80b in the developer container 80 and flows into the replacement unit. As a result, a suction air flow is generated in the developing unit 23 and toner scattering from the developing unit 23 is suppressed.

  As described above, also in the image forming apparatus configured as in the fifth embodiment, the filter 76 that collects toner in the replacement unit that is replaced in a replacement cycle shorter than the maintenance cycle of the developing unit 23. Is installed. Accordingly, toner scattering can be stably reduced over time, and maintenance workability can be improved.

  In each of the above embodiments, the developing unit 23 is configured separately from the process cartridge 20. On the other hand, the developing unit 23 can be integrated with the process cartridge 20 (except in the case of the second embodiment). Furthermore, the developing unit 23 can be integrated with at least one of the photosensitive drum 21, the charging unit 22, the transfer unit 24, the cleaning unit 25, and the toner supply unit 32.

  In each of the above embodiments, the developer used in the developing unit 23 is a two-component developer composed of the toner T and the carrier C. On the other hand, as the developer used in the developing unit 23, a one-component developer having no carrier C can be used. Even in such a case, the toner scattering is reduced by the gas in the developing unit 23 being conveyed by the gas conveying path 71, and the replacement cycle of the replacement unit including the filter 76 is set shorter than the maintenance cycle of the developing unit 23. By doing so, the effect can be maintained over time.

  In the above embodiments, the replacement unit including the filter 76 is the waste toner container 75, the process cartridge 20, and the toner bottle 33. However, the replacement unit is not limited to this, and may be any unit that can be replaced in a cycle shorter than a predetermined maintenance cycle determined for the developing unit 23.

  Furthermore, the present invention is not limited to the above-described embodiments, and it is apparent that each embodiment can be modified as appropriate within the scope of the technical idea of the present invention, other than suggested in each embodiment. It is. Further, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiments, and the number, position, shape, and the like that are suitable for implementing the present invention can be used.

1 is a configuration diagram illustrating an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is a side cross-sectional view showing an image forming unit in the image forming apparatus of FIG. 1. It is sectional drawing which shows the AA cross section of the image development part in the image formation part of FIG. It is a block diagram which shows the principal part of the image forming apparatus in Embodiment 2 of this invention. It is a block diagram which shows the principal part of the image forming apparatus in Embodiment 3 of this invention. FIG. 6 is a cross-sectional view showing a BB cross section of a toner bottle in the image forming apparatus of FIG. It is a block diagram which shows the image forming apparatus in Embodiment 4 of this invention. It is a block diagram which shows the principal part of the image forming apparatus in Embodiment 5 of this invention. FIG. 9 is a cross-sectional view showing a CC cross section of a developing unit in the image forming apparatus of FIG. 8.

Explanation of symbols

1 image forming apparatus body (apparatus body), 2 writing unit,
20, 20Y, 20M, 20C, 20BK Process cartridge,
21 photosensitive drum (image carrier), 22 charging unit,
23, 23Y, 23M, 23C, 23BK Developing unit (developing device),
23a developing roller, 23b first conveying screw,
23c second conveying screw, 23d doctor blade,
23e partition member, 23f supply port, 23g opening,
24 transfer bias roller, 25 cleaning section,
26 Case, 26a Wall, 27 Intermediate transfer belt,
29 Intermediate transfer belt cleaning section,
32, 32Y, 32M, 32C, 32BK toner supply unit,
33 toner bottle (toner container), 33a inlet, 33b wall,
34 toner hopper section, 36 gas inflow section, 37 toner storage section,
38 conveying coil, 70 conveying tube (collected toner conveying path),
71 tube (gas transport path), 75 waste toner container,
76 Filter, 77 Air pump, 78 Suction fan,
80 developer container, 80a developer container, 80b gas outlet,
80c wall surface, 81 sealing member.

Claims (21)

A developing unit that develops the latent image formed on the image carrier and is maintained in a predetermined cycle;
An exchange unit that includes a filter formed so as to be able to collect toner, and is exchanged and installed in the image forming apparatus main body in a cycle shorter than a maintenance cycle of the developing unit;
A gas conveyance path communicating between the developing unit and the replacement unit,
The image forming apparatus, wherein the gas in the developing unit is configured to flow into the replacement unit via the gas transport path and to flow out of the replacement unit via the filter. The image forming apparatus according to claim 1, wherein the gas conveyance path includes an air pump. The image forming apparatus according to claim 1, wherein the gas conveyance path includes a suction fan. 4. The image forming apparatus according to claim 1, wherein the replacement unit is a waste toner container that stores untransferred toner collected from the image carrier as waste toner. The exchange unit is a process cartridge in which at least one of a charging unit that charges the image carrier and a cleaning unit that cleans the image carrier and the image carrier are integrated. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The image forming apparatus according to claim 1, wherein the replacement unit is a toner container that stores toner to be supplied to the developing unit. The image forming apparatus according to claim 1, wherein the replacement unit includes a wall portion that partitions a space into which the gas flows. The developing unit includes an opening communicating with the gas conveyance path,
The image forming apparatus according to claim 1, wherein the opening is sealed with a sealing member when the developing unit is in a new state. The developing unit includes a developer container that stores a two-component developer supplied into the developing unit,
The image forming apparatus according to claim 8, wherein the opening is provided in the developer container. The image forming apparatus according to claim 1, comprising a plurality of the developing units. The image forming apparatus according to claim 10, wherein the replacement unit is a toner container that stores black toner among a plurality of toner containers that respectively supply toner to the plurality of developing units. 12. The image forming apparatus according to claim 10, wherein the replacement unit is a toner container having the largest internal volume among a plurality of toner containers that respectively supply toner to the plurality of developing units. An exchange unit that is installed in a replaceable manner with respect to the image forming apparatus main body,
It has a filter formed to collect toner,
It is configured to be connectable to a gas conveyance path that communicates with a developing unit that develops a latent image formed on an image carrier,
It is replaced in a cycle shorter than the maintenance cycle of the developing unit,
An exchange unit, wherein the gas in the developing unit is configured to flow into the inside through the gas transport path and flow out to the outside through the filter. 14. The replacement unit according to claim 13, wherein the replacement unit is a waste toner container that stores untransferred toner collected from the image carrier as waste toner. 2. The process cartridge according to claim 1, wherein at least one of a charging unit that charges the image carrier and a cleaning unit that cleans the image carrier and the image carrier are an integrated process cartridge. The exchange unit according to claim 13 or claim 14. 16. The replacement unit according to claim 13, wherein the replacement unit is a toner container in which toner to be supplied to the developing unit is accommodated. The exchange unit according to any one of claims 13 to 16, further comprising a wall portion that partitions a space into which the gas flows. A developing device that develops a latent image formed on an image carrier and is maintained in a predetermined cycle,
It is configured to be connectable to a gas conveyance path that communicates with an exchange unit that includes a filter that is configured to collect toner.
Maintenance is performed in a cycle longer than the replacement cycle of the replacement unit in the image forming apparatus main body,
A developing device characterized in that gas in the apparatus flows into the replacement unit through the gas transport path and flows out of the replacement unit through the filter. Comprising an opening communicating with the gas conveyance path;
The developing device according to claim 18, wherein the opening is sealed with a sealing member when in a new state. A developer container for storing a two-component developer to be supplied into the apparatus;
The developing device according to claim 19, wherein the opening is provided in the developer container. The image carrier, a charging unit that charges the image carrier, a transfer unit that transfers a toner image formed on the image carrier to a transfer material, and a cleaning unit that cleans the image carrier. 21. The developing device according to claim 18, wherein the developing device is integrated with at least one of a toner container in which toner is stored.

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