JP4634833B2 - Developing device, image forming apparatus, and image forming method - Google Patents

Description

  The present invention relates to a developing device that performs development using a developer containing toner and a carrier, an image forming apparatus such as a copying machine, a facsimile, and a printer having the developing device, and an image forming method using these devices. .

In an image forming apparatus such as a copying machine, a facsimile machine, or a printer, a developing device that develops an image carrier such as a photoconductor using a two-component developer containing toner and carrier is disclosed in, for example, [Patent Document 1] to [ Patent Document 9] and the like are well known.
In such a developing device using a two-component developer, toner is consumed as it adheres to the image carrier by a developing operation. Therefore, in order to perform good image formation, toner is replenished to the developer so that the toner density of the developer is maintained appropriately.

  The replenished toner is agitated and mixed with the developer present in the developing device by the agitating and mixing member. However, if the agitating and mixing is insufficient, the replenished toner is not sufficiently charged and the toner is scattered. It may cause. When toner scattering occurs, the inside of the image forming apparatus is contaminated with toner, and when the degree is poor, the scattered toner may adhere to the photosensitive member and stain the image. In addition, if the stirring and mixing is insufficient, the toner may be subjected to development while being in the form of an aggregate, and the image quality may be deteriorated.

Therefore, in [Patent Document 3], [Patent Document 8], [Patent Document 9], and the like, a technique for performing such agitation and mixing is proposed.
The technology described in [Patent Document 3] is provided with a developer containing portion that has been used for toner image formation and has a reduced toner concentration in addition to the developer stirring and conveying portion that has been used conventionally, and is replenished with toner. This is a proposed configuration.

  The technique described in [Patent Document 8] reduces the mechanical load exerted on the developer by the stirring assisting member during stirring by providing a stirring assisting member that is inclined in the direction of accelerating the flow of the developer on the screw having a spiral structure. Thus, the stirring and mixing performance of the developer and the replenishing toner is improved.

  In the technique described in [Patent Document 9], a toner supply screw is provided on the same axis as the developer agitating and conveying screw and an agitating member is provided between these screws for the purpose of eliminating aggregation of the replenishing toner. It is. According to this technique, since the replenishment toner is mixed in a state in which the aggregation is eliminated by the stirring member, the toner is easily mixed with the developer. Further, since the toner is replenished from the axial direction of the developer agitating member, the replenished toner and the developer are easily mixed as compared with the case where the toner is replenished from the upper surface of the developer.

JP 2004-347726 A JP-A-10-282776 JP 2002-182463 A JP 2002-014541 A JP 2002-091123 A JP 2000-137376 A JP 05-127523 A JP 05-019621 A JP 2002-148915 A

  However, in the configuration described in [Patent Document 3], a storage unit for storing a developer having a low toner concentration is newly provided in the developer agitating and conveying unit, which increases the size of the apparatus. In addition, the developer agitating and conveying section is further provided with a mixing agitation area for the low toner concentration developer and the replenishment toner, so that the time for the developer to receive a load from the agitating member due to the mixing agitation becomes longer, and the developer is required as a whole. There is a possibility of receiving a larger load. In addition, by supplying toner to such a container, the unevenness of the toner concentration in the developer is reduced, but the toner replenishment method and the mixing and stirring method are conventional methods of stirring with a screw. For this reason, the possibility of partial unevenness of the toner density due to the top-slip of the replenishing toner and insufficient mixing and stirring has not been completely eliminated. In addition, depending on the type of image formed, there is a possibility that a deviation in toner density occurs inside the housing portion, and even if the toner is supplied to the housing portion, the deviation in toner density may not be resolved.

Further, in the configuration described in [Patent Document 8], since the auxiliary stirring member is provided, the mechanical load exerted on the developer is increased as compared with a screw composed of an agitating member having only a spiral structure. In addition, since the stirring assisting member is tilted in the developer flow direction to reduce the mechanical load on the developer, the ability to take in the replenishment toner into the developer and mix and stir is reduced. It is not sufficient to improve the mixing and stirring of the toner.
In addition, in the configuration described in [Patent Document 9], toner aggregation can be prevented, but the replenishment toner is not completely mixed into the developer and comes out to the developer powder surface and is conveyed as it is. There is a possibility that.

As described above, a technique for improving the dispersibility of the replenishing toner has been proposed, but a technique for increasing the dispersibility and reducing the mechanical load on the developer has not yet been proposed.
That is, in order to charge the toner constituting the developer, it is necessary to bring the carrier and the toner into contact with each other. Therefore, although a load by the stirring member or the like is necessary to some extent, an excessive load is applied or more than necessary. When a load is applied for a long time, a part of the toner adheres to the carrier or the coat layer of the carrier peels off due to friction or collision between the toner and the carrier, and the carrier is charged with toner. The ability will be reduced.

  In addition, when an excessive load is applied or when the load is applied for a longer time than necessary, not only the carrier but also the toner is buried or detached from the additive applied to the toner due to the excessive load. The charging ability will be reduced. At the same time, the peeling off of the additive and carrier coat layer released from the toner floats in the developer in the developing device, and there is a risk of impairing the charging stability of the developer.

  As described above, when the charging failure of the developer occurs, the inside of the image forming apparatus is contaminated with the scattered toner, the image quality is deteriorated due to the background dirt or the toner scattering, and the charging becomes unstable. As a result, there is a risk that the image density is uneven or blurred. For this reason, even if the dispersibility of the toner is improved, if the load applied to the developer is increased, the same problem as when the dispersibility of the toner is poor occurs.

  Further, when the mechanical load on the developer is large, not only the developer but also the developing device and the entire image forming apparatus have problems such as an increase in power consumption and rapid wear of apparatus components. . The increase in power consumption results in adverse effects on the environment, and wear of equipment components shortens the life of equipment and increases the number of maintenance, which also increases equipment downtime for the user. It may lead to the result.

  For these reasons, in order to improve the mixing agitation of the replenishment toner and completely prevent problems such as toner slipping, the mechanical load applied to the developer during the mixing agitation is not increased more than in the past, It is necessary to increase dispersibility. For that purpose, the improvement of the dispersibility by the replenishment method is more desirable than the improvement of the dispersibility by the stirring member. In particular, it is considered that by supplying the bottom surface instead of replenishing the developer surface, it is possible to prevent a state where the replenished toner is not taken into the developer and slips upward.

  [Patent Document 7] proposes a technique for replenishing toner from below the stirring member, and it is considered that this technique prevents the toner from slipping up. However, in this technique, the relationship between the position and mode where the stirring action occurs by the stirring member and the toner replenishment position is unclear, and it is unclear whether the stirring and mixing performance is sufficient.

  In view of such circumstances, the present invention is a developing device that performs development using a developer containing a toner and a carrier, in which a replenisher such as toner is well agitated and mixed with the developer and the developer is mixed. It is an object of the present invention to provide a developing device with a reduced mechanical load, an image forming apparatus such as a copying machine, a facsimile, and a printer having the developing device, and an image forming method using these devices.

In order to achieve the above object, the invention described in claim 1 is directed to agitating and conveying a stirrer conveying member that conveys a developer containing toner and carrier while stirring, and a replenisher containing at least one of the toner and carrier. A replenishing means for replenishing the developer agitating and conveying area by a member; and a replenishing port for replenishing the replenishing agent to the agitating and conveying area by the replenishing means, wherein the replenishing means A developing device that replenishes the upstream portion in the transport direction of the developer by the agitation transport member from below the stirring transport region through the replenishment port, and the replenishment port faces the downstream side in the transport direction A push-opening opening / closing member that opens in a direction, and the replenishing means includes an airflow forming means for forming an airflow for replenishing the replenisher from the replenishing port, and the airflow forming means There the replenisher by opening the supply opening pushes open the closing member in the direction by the air flow formed in the developing unit to be replenished from the replenishing port.

According to a second aspect of the present invention, in the developing device according to the first aspect, a replenishing direction of the replenisher from the replenishing port to the stirring and conveying region is non-parallel to the conveying direction .

According to a third aspect of the present invention, in the developing device according to the first or second aspect of the present invention, the developing device further includes an exhaust port that exhausts the airflow formed by the airflow forming unit.

  According to a fourth aspect of the present invention, in the developing device according to the third aspect, the air flow path by the air flow forming means is a closed path passing through the supply port and the exhaust port.

According to a fifth aspect of the invention, in the developing device according to any one of claims 1 to 4, and supplying only the air flow by the air current formation means at the rising edge.

According to a sixth aspect of the invention, in the developing device according to any one of claims 1 to 5, characterized by constantly supplied airflow by the airflow forming means.

Invention of claim 7 wherein the amount of air flow formed in the developing device according to any one of claims 1 to 6, by the air flow forming means in accordance with the fluidity of the developer to be supplied to said replenisher It has the control means which controls.

  According to an eighth aspect of the present invention, in the developing device according to any one of the first to seventh aspects, the replenishing means includes a replenisher transport member for replenishing the replenisher from the replenishing port. Features.

  According to a ninth aspect of the present invention, in the developing device according to the eighth aspect of the present invention, the replenisher transport member is shaped to close the replenishing port.

According to a tenth aspect of the present invention, in the developing device according to any one of the first to ninth aspects, the first portion connected to the supply port from below and the forming direction of the first portion are not parallel. And a second portion connected to the first portion from any direction, and having a transport path through which the replenisher is transported by the replenishing means.

According to an eleventh aspect of the present invention, there is provided an image forming apparatus comprising the developing device according to any one of the first to tenth aspects.

According to a twelfth aspect of the present invention, there is provided an image forming method for forming an image using the developing device according to any one of the first to tenth aspects or the image forming apparatus according to the eleventh aspect .

The present invention replenishes an agitating and conveying region of the developer by the agitating and conveying member with an agitating and conveying member that conveys the developer containing the toner and the carrier while stirring and a replenisher containing at least one of the toner and the carrier. And a replenishing port for replenishing the replenisher to the stirring and conveying area by the replenishing means, and the replenishing means passes the replenishing agent through the replenishing port and below the agitating and conveying area. A developing device that replenishes the upstream portion of the developer conveying direction by the agitating and conveying member , wherein a push-open type opening and closing member that opens the replenishing port in a direction toward the downstream side in the conveying direction is provided. And the replenishing means includes airflow forming means for forming an airflow for replenishing the replenisher from the replenishing port, and the opening / closing portion is formed by the airflow formed by the airflow forming means. Since the press out opening the supply opening in the direction is the replenishment to the developing device that supplies from the same supply port, loosen the developer by preventing careless of replenisher was formed by the air flow forming means airflow The flowability is increased to replenish the developer in this state, and the open / close member that opens in the direction toward the downstream side of the developer conveyance direction by this air flow prevents clogging, backflow, and retention of the developer at the replenishing port. By preventing it well, the replenisher can be well agitated and mixed with the developer containing the toner and the carrier, the toner concentration can be kept uniform, and the toner can be stably and sufficiently charged. In addition to preventing scattering and toner contamination, the mechanical load on the developer during stirring and mixing can be reduced, and good development can be performed over time. That.

  If it has an exhaust port for exhausting the airflow formed by the airflow forming means, the replenisher is prevented from slipping, and the developer is loosened by the airflow formed by the airflow forming means to increase the fluidity. By replenishing the developer in the state, the replenisher can be well mixed with the developer including the toner and the carrier, the toner concentration can be kept uniform, and the toner can be stably stabilized. By sufficiently charging and preventing an increase in internal pressure by exhausting from the exhaust port, toner scattering can be prevented, toner contamination can be prevented, and the mechanical load on the developer during stirring and mixing can be reduced. It is possible to provide a developing device that can perform good development over time.

  If the air flow path by the air flow forming means is a closed path passing through the replenishing port and the exhaust port, the replenisher is prevented from slipping and the developer is loosened by the air flow formed by the air flow forming means. By increasing the flowability and replenishing the developer in this state, the replenisher can be well mixed with the developer containing toner and carrier, and the toner concentration can be kept uniform. In addition, the toner is stably and sufficiently charged, the increase in internal pressure is prevented by exhausting from the exhaust port, and the air flow path is closed to prevent toner scattering and to prevent toner contamination. It is possible to provide a developing device capable of preventing the development of the developer and reducing the mechanical load applied to the developer at the time of stirring and mixing, and capable of performing good development over time. Kill.

  If only the airflow is supplied by the airflow forming means at the time of rising, the replenisher is prevented from slipping, and the developer is quickly loosened at the time of rising by the airflow formed by the airflow forming means to increase the fluidity. By supplying the replenisher to the developer, the replenisher can be well mixed with the developer including the toner and the carrier, the toner concentration can be kept uniform, and the toner can be stably and sufficiently supplied. The toner can be charged to prevent toner scattering and toner contamination, and the mechanical load applied to the developer during stirring and mixing can be reduced, and good development can be performed over time. A developing device capable of being provided can be provided.

  If the airflow is constantly supplied by the airflow forming means, the replenisher is prevented from slipping, and the developer is constantly loosened by the airflow formed by the airflow forming means to increase the fluidity and replenish the developer in this state. By replenishing the agent and preventing the developer from clogging, backflow, and retention at the replenishing port with the constantly supplied airflow, the replenisher can be well mixed with the developer including the toner and the carrier, The toner density can be kept uniform, and the toner can be stably and sufficiently charged to prevent toner scattering, to prevent toner contamination, and to reduce the mechanical load on the developer during stirring and mixing. It is possible to provide a developing device that can be made small and can perform good development over time.

  If the control means for controlling the amount of the air flow formed by the air flow forming means according to the fluidity of the developer replenished with the replenishment agent is provided, the replenishment agent is prevented from slipping and the developer fluidity is maintained. Accordingly, the developer is appropriately loosened by the air flow formed in a state where the amount is adjusted by the air flow forming means to increase the fluidity, and the replenishment agent is replenished to the developer in this state. Can be satisfactorily mixed with the developer containing the toner, the toner concentration can be kept uniform, and the toner can be stably and sufficiently charged to prevent toner scattering and toner contamination. At the same time, it is possible to provide a developing device that can reduce the mechanical load applied to the developer at the time of stirring and mixing and can perform good development over time.

  If the replenishing means has a replenisher transport member for replenishing the replenisher from the replenishment port, the replenisher is prevented from slipping and the replenisher transported by the replenisher transport member is removed from the replenishment port. By replenishing, the replenisher can be well agitated and mixed with the developer containing toner and carrier, the toner concentration can be kept uniform, and the toner can be stably charged sufficiently to prevent toner scattering. To provide a developing device that can prevent contamination of toner, reduce the mechanical load applied to the developer during stirring and mixing, and perform good development over time Can do.

  If the replenisher transport member has a shape that closes the replenishment port, the replenisher is prevented from slipping, the replenisher transported by the replenisher transport member is replenished from the replenishment port, and the replenisher transport By preventing clogging, backflow and stagnation of the developer at the replenishing port with the member, the replenisher can be well mixed with the developer containing the toner and the carrier, and the toner concentration can be kept uniform, In addition, the toner can be stably and sufficiently charged to prevent toner scattering and toner contamination, and the mechanical load on the developer during stirring and mixing can be reduced. It is possible to provide a developing device capable of performing good development.

  If the replenishment direction of the replenishment agent from the replenishment port to the stirring and transporting region is non-parallel to the transporting direction, the replenishment agent is prevented from slipping and the replenishment agent is supplied in this direction. By properly preventing clogging, backflow and stagnation of the developer, the replenisher can be well mixed with the developer containing the toner and the carrier, the toner concentration can be kept uniform, and the toner The toner can be stably and sufficiently charged to prevent toner scattering and toner contamination, and the mechanical load applied to the developer during stirring and mixing can be reduced. A developing device capable of performing development can be provided.

  A first portion connected to the supply port from below; and a second portion connected to the first portion from a direction non-parallel to the direction in which the first portion is formed. If the transport path for transporting the agent is provided, the replenisher is prevented from slipping, and the first portion and the second portion disposed in this direction are clogged with the replenishment port and in the vicinity thereof. By preventing the backflow and staying well, the replenisher can be well mixed with the developer containing the toner and the carrier, the toner concentration can be kept uniform, and the toner can be stably and sufficiently The toner can be charged to prevent toner scattering and toner contamination, and the mechanical load applied to the developer during stirring and mixing can be reduced, and good development can be performed over time. A developing device capable of Door can be.

The present invention resides in an image forming apparatus having the developing device according to any one of claims 1 to 10 , and thus has a developing device that exhibits the above-described effects. The replenisher is well agitated and mixed with the developer containing toner and carrier, the toner density is kept uniform, and the toner is stably and sufficiently charged to prevent toner scattering and prevent toner contamination In addition, an image forming apparatus capable of reducing the mechanical load applied to the developer at the time of stirring and mixing and performing good development over time, thereby performing good image formation over time. Can be provided.

Since the present invention is an image forming method for forming an image using the developing device according to any one of claims 1 to 10 or the image forming device according to claim 11 , the above-described effects can be obtained. A developing device or an image forming device that exhibits the above-described effects. In such a developing device, the replenisher is prevented from slipping, the replenisher is well agitated and mixed with the developer containing toner and carrier, and the toner concentration is uniform. The toner is stably and sufficiently charged to prevent toner scattering, toner contamination is prevented, and the mechanical load applied to the developer during stirring and mixing is reduced, which is good over time. Thus, it is possible to provide an image forming method that can perform good image formation over time.

  FIG. 1 shows an outline of an image forming apparatus to which the present invention is applied. The image forming apparatus 100 is a multifunction peripheral of a copying machine, a printer, and a facsimile machine, and can perform image forming processing based on an image signal corresponding to image information received from the outside. This is the same when the image forming apparatus 100 is used as a facsimile. The image forming apparatus 100 can form an image on a sheet-like recording medium using not only plain paper generally used for copying, but also OHP sheets, cardboard, cardboard, cardboard, and envelopes. It is.

The image forming apparatus 100 may be another type of image forming apparatus, that is, for example, a printer, a facsimile machine, a copier, a copier / printer multifunction machine, or the like.
Further, the image forming apparatus 100 forms a single color image, but may be capable of forming an image of two or more colors or a full color image.

  The image forming apparatus 100 includes an image forming unit 4 that performs image formation, a paper discharge tray 15 disposed above the image forming unit 4, a document reading unit 16 disposed above the paper discharge tray 15, A sheet feeding device 17 disposed below the image forming unit 4, a control unit (not shown) including a CPU, a memory and the like for controlling the overall operation of the image forming device 100, and predetermined information are displayed to the user. A display device (not shown) and an operation panel (not shown) provided with an input device (not shown) that allow a user to input predetermined information.

  The image forming unit 4 is a photosensitive drum as a drum-shaped image carrier disposed in the center of the image forming unit 4. The photosensitive drum 5 is rotated in a clockwise direction indicated by an arrow A in the drawing by a driving source (not shown). And an optical scanning device 14 for forming a latent image corresponding to image information read by the document reading unit 16 or image information input from the outside. is doing.

  The image forming unit 4 is also developed around the photoconductor 5 along the rotation direction A as a charging unit 6 for charging the photoconductor 5 and with the photoconductor 5 carrying toner. And a developing device 8 as a developing means for forming a visible image, and a downstream side of the developing device 8 in the rotation direction A, facing the photoconductor 5 and detecting the toner density on the photoconductor 5. And an image density sensor 18 which is a reflection type density sensor as a toner density sensor.

  The image forming unit 4 is also disposed around the photoconductor 5 on the downstream side of the image density sensor 18 in the rotation direction A so as to oppose the photoconductor 5 and displays a toner image on the photoconductor 5 in a sheet form (not shown). A transfer device 20 for transferring a sheet on which a toner image is transferred while transferring to a sheet as a recording medium, and a residual toner remaining on the photosensitive member 5 after the transfer is performed by the transfer device 20 5 has a cleaning device 2 as a cleaning means for scraping and cleaning from above, and a static elimination device as a static elimination means (not shown) that removes residual charges on the photoreceptor 5 cleaned by the cleaning device 2 by static elimination. .

  The image forming unit 4 also includes a registration roller 19 that feeds the sheet conveyed from the sheet feeding device 17 to a position where the photosensitive member 5 and the transfer device 20 face each other at a predetermined timing according to the position of the toner image, and a transfer The image forming apparatus includes a fixing device 10 as a fixing unit for fixing the toner image on a sheet carrying the toner image on the photosensitive member 5 transferred by the device 20.

The photoreceptor 5 is obtained by applying a photosensitive organic photoreceptor to an aluminum tube and forming a photosensitive layer. The diameter of the photoreceptor 5 is 30 mm, and the linear velocity is 185 mm / sec.
The paper feeding device 17 is arranged in multiple stages and each of the paper feeding trays 31 on which the paper is stacked, and the paper which is provided above the paper feeding tray 31 and on which the image is formed on one side by the image forming unit 4 is temporarily stacked. The double-sided tray 32 that refeeds the image forming unit 4, the paper feeding tray 31, the paper feeding roller 33 that feeds the paper stacked on the double-sided tray 32 toward the image forming unit 4, and the paper feeding roller 33 Conveying rollers 34 that carry the paper and further convey it toward the image forming unit 4 are provided.

  The image density sensor 18 includes a light-emitting element and a light-receiving element (not shown). The image density sensor 18 indicates the amount of poorly charged toner adhering to a portion other than the image portion on the photoconductor 5, in other words, the degree of occurrence of scumming. The light emitted from the element and reflected by the toner image is received by the light receiving element, and is detected by the reflection density. The image density sensor 18 also detects the toner adhesion amount, that is, the image density in the reference toner image formed on the image portion on the photoconductor 5.

The transfer device 20 includes a medium-resistance belt 21 made of a rubber material, a driving roller 22 around which the belt 21 is wound, and a driven roller 23 around which the belt 21 is wound together with the driving roller 22. And a contact / separation means (not shown) that contacts and separates the belt 21 with respect to the photoreceptor 5 at a predetermined timing suitable for transfer.
The image forming apparatus 100 forms an image by transferring a toner image formed on the photoreceptor 5 onto a sheet by the transfer device 20.

The fixing device 10 includes a heating roller 25 that generates heat, and a pressure roller 26 that is in pressure contact with the heating roller 25, and a toner image carried on the paper is melted by heating and pressed by pressure contact. To settle.
The paper discharge tray 15 is disposed in the body of the image forming apparatus 100. The image forming apparatus 100 is an in-body discharge type image forming apparatus.

The optical scanning device 14 irradiates the photosensitive member 5 with a beam L corresponding to an image to be formed between the charging device 6 and the developing device 8 in the direction A, thereby forming a latent image according to the document information.
Therefore, after the photosensitive member 5 is charged by the charging device 6, a latent image is formed by the beam L and developed by the developing device 8.

  As shown in FIG. 2, the developing device 8 includes a developing case 55 that is a developing device as a casing having an opening in a portion facing the photoconductor 5, and the photoconductor drum 5 so as to face the photoconductor 5 from the opening. A developing roller 51 that is a developer carrying member that is disposed in close proximity to and rotates in the direction of arrow E, and a developing doctor that is a doctor blade that regulates the developer on the developing roller 51 to a certain height. A developing blade 52 as a developer regulating member and a first agitating and conveying member as a first agitating and conveying member which are arranged in parallel to each other below the developing case 55 and agitate while conveying the developer so as to circulate. A first conveying screw 53 and a second agitating screw 54 as a second agitating and conveying member as a conveying auger, and a toner for detecting the concentration of toner contained in the developer in the developing case 55 And a toner density sensor 90 as degrees detection means.

The developer is a two-component developer containing a toner and a carrier. The amount of developer in the developing case 55 is 200 g.
The carrier has a particle size of about 20 to 200 μm, and the surface is made of a conventionally known iron powder, ferrite powder, magnetite powder, magnetic resin or the like with an amino resin, polyvinyl and polyvinylidene resin, polystyrene resin, silicon resin, or the like. A coated one is used. In this embodiment, the average particle diameter of the carrier is 35 μm.

  The toner is mixed with a binder resin, a wax component, a colorant, and in some cases, a charge control agent using a mixer, etc., kneaded using a kneader such as a hot roll or an extruder, and then cooled and individualized. Is conventionally pulverized toner such as a pulverized toner obtained by pulverizing with a jet mill or the like, and a toner using a polymerization method, and has a particle size of about 2 to 10 μm. In this embodiment, the average particle diameter of the toner is 6 μm, the degree of aggregation is 10, and the toner concentration is 8 wt%.

Although not shown in the drawing, the developing roller 51 includes a developing sleeve that is rotationally driven in the E direction in which a non-magnetic material is formed in a cylindrical shape, and a fixed magnet roller in which a plurality of magnetic poles are magnetized. A magnet roller is disposed inside the developing sleeve.
The developing sleeve is made of aluminum, but may be made of brass, stainless steel, conductive resin or the like as long as it is a non-magnetic material. The diameter of the developing sleeve is 18 mm.

On the surface of the developing sleeve, a sandblasting process or a process of forming a plurality of grooves having a depth of several tens to several hundreds of μm is performed. The developing sleeve is rotationally driven in the E direction at a linear velocity of 278 mm / sec by a driving mechanism (not shown) similar to the driving mechanism of the first conveying screw 53 and the second stirring screw 54, which will be described later with reference to FIG.
The developing blade 52 is made of, for example, an extruded product of aluminum or stainless steel, and is fixed at a distance of about several hundred microns from the surface of the developing sleeve.

  The developer is magnetically attracted as a magnetic brush on the developing sleeve by the magnetic force of the magnet roller in the developing roller 51, and the developing sleeve surface is carried by the irregularities on the developing sleeve surface as the developing sleeve rotates, and the developing blade After being uniformed to a uniform thickness at 52, it is conveyed to the surface of the opposing photoconductor 5. Of the conveyed developer, only the toner is electrostatically attached to the electrostatic latent image formed on the surface of the photoconductor 5 for development. Only the toner adheres to the photosensitive member 5, and the toner that has not been used for development and the carrier that has transported the toner are again carried into the developing device 8 along with the rotation of the developing sleeve so as to be separated from the developing sleeve. Due to the magnetic force of the formed magnet roller, it is discharged to the developer agitating and conveying area described later.

  In this embodiment, as described above, the diameter of the photoreceptor 5 is 30 mm, the linear velocity is 185 mm / sec, the diameter of the developing sleeve is 18 mm, and the linear velocity is 278 mm / sec. Therefore, the ratio of the linear velocity of the developing sleeve to the linear velocity of the photosensitive member 5 is 1.5. However, if the linear velocity ratio is larger than this, there is no missing image even at a lower toner concentration, and the image density A sufficient image can be obtained.

  As shown in FIG. 3 or FIG. 4, the developing device 8 also includes a replenisher cartridge 41 that contains a replenisher containing toner and a carrier for replenishment in the developing case 55, and replenishment in the replenisher cartridge 41. The replenisher transport path 42 constituting the transport path for guiding the developer to the developing case 55, the replenisher transport path 42 and the developing case 55 are connected, and the replenisher is guided from the replenisher transport path 42 into the developing case 55. A replenisher supply portion 44 and a replenisher transport screw (not shown) that is disposed inside the replenisher cartridge 41 and feeds the replenisher in the replenisher cartridge 41 to the replenisher transport path 42 by rotation.

  The developing device 8 is also driven from the replenisher cartridge 41 by a replenisher transporting motor 43 for rotating the replenisher transporting screw to feed the replenisher in the replenisher cartridge 41 to the replenisher transporting path 42 and the replenisher transporting screw. The discharge type powder pump 50 serving as an air flow forming means for sending the supplied replenisher mixed with air, and the replenisher in the replenisher transport path 42 sent by the powder pump 50 is sent into the developing case 55. A pump 46 serving as an air flow forming means for forming an air flow for discharging, and an exhaust unit 45 for releasing the air flow sent into the developing case 55 by the pump 46 and sending it to the pump 46 again.

  The developing device 8 also stores a developer collection container (not shown) that stores and collects excess developer discharged from the development case 55, and guides the developer discharged from the development case 55 to the developer collection container. 2 and 3, a developer transport path indicated by reference numeral 48, and a developer transport screw indicated by reference numeral 63 in FIG. 2 and a developer transport screw 63 that transports the developer toward the developer recovery container by rotation, and a developer transport screw 63. A developer transport motor (not shown) for rotational driving, and a developer discharge portion denoted by reference numeral 49 in FIGS. 2 and 3 are connected to the developing case 55 and the developer transport path 48. The developer conveying screw 62 and the developer transport motor are provided as necessary, and may be omitted.

  As shown in FIG. 4, the developing device 8 is also disposed in the replenishing agent replenishing section 44 and disposed in the exhaust section 45 and the replenishing port 40 that connects the developing case 55 and the replenishing agent transport path 42. The case 55 and the pump 46 are connected to each other, and an exhaust port 91 that exhausts the airflow formed by the pump 46 is provided. The air flow path formed by the pump 46 has a replenishment port 40 and an exhaust port 91 and is a closed path to prevent the developer and the replenisher from being scattered.

  The replenisher in the replenisher cartridge 41 is replenished little by little into the developing case 55 via the replenisher transport path 42. The replenishment amount of the replenisher is adjusted by controlling the rotation amount of the replenisher transport screw by the replenisher transport motor 43. The pump 46 forms an air flow for supplying the replenisher from the replenishing port 40. The pump 46 and the powder pump 50 form an air flow having a pressure and an amount sufficient to guide the replenisher sent into the replenisher transport path 42 by the replenisher transport motor 43 into the developing case 55.

  The rotation of the replenisher transport motor 43 and the driving of the pump 46 and the powder pump 50 are controlled by the control means. The pump 46 and the powder pump 50 are basically driven synchronously. However, as will be described later, when the pump 46 is driven only to improve and maintain the fluidity of the developer, the powder pump 50 is driven. Not performed.

As shown in FIG. 2, the developing case 55 is disposed at a portion corresponding to the developer discharge portion 49, and the total amount increases due to the supply of the replenisher from the replenisher cartridge 41, and the excess developer is removed. A developer discharge port 64, which is an opening for discharging to the outside of the developing case 55, is provided on the side wall 47 on the second conveying screw 54 side.
As will be described later, the developer that has overflowed due to the supply of the replenisher from the carrier cartridge 44 into the developing case 55 is transferred to the developer collecting container, the developer discharge port 64, the developer discharge portion 49, and the developer transport. It flows in through the passage 48.

The replenisher cartridge 41 may contain toner instead of the replenisher. In this case, the replenisher cartridge 41 contains toner as a replenisher. With the same configuration, the toner and the carrier can be supplied from separate cartridges. However, if a replenisher containing toner and carrier is used, the component ratio is originally close to that of the developer, so the time from replenishment of the replenisher to mixing and even dispersion is shortened, and stirring and mixing are completed quickly. . When only the toner is supplied, the developer recovery container, the developer transport path 48, the developer transport screw 63, the developer discharge port 64, the developer transport motor, and the developer discharge section 49 are not necessarily required.
The developer recovery container, the developer transport path 48, the developer transport screw 63, the developer discharge port 64, the developer transport motor, and the developer discharge portion 49 constitute a recovery means.

Each of the replenisher cartridge 41 and the developer recovery container is detachable from the main body of the developing device 8, specifically, is detachable from the replenisher transporting path 42 and the developer transporting path 48, and each is housed inside. When the replenisher is used up, the developer is replaced.
The method for transporting the toner, carrier or developer may be a method using a screw as described later in addition to a method using a pump mechanism for feeding powder as in this embodiment.

The developing case 55 also divides the developing chamber 58 containing the first conveying screw 53 and the developer, the agitating chamber 59 containing the second conveying screw 54 and the developer, the developing chamber 58 and the agitating chamber 59 into partitions. And a partition wall 81 as a partition plate.
Since the first conveying screw 53 faces the developing roller 51 so as to supply the developer to the developing roller 51, the developing chamber 58 is positioned closer to the developing roller 51 in the developing chamber 58 and the stirring chamber 59. is doing.

  The first conveying screw 53 and the second conveying screw 54 are respectively configured by rotating shafts 83 and 84 having a shaft diameter of 5 mm that form the center of rotation, and spirals, that is, spiral protrusions formed on the rotating shafts 83 and 84. And screw portions 85 and 86 as fins having an outer diameter of 12 mm. The first conveying screw 53 and the second conveying screw 54 are arranged in parallel to each other and are arranged in parallel to the developing roller 51.

  The first conveying screw 53 and the second conveying screw 54 are rotated in the directions of arrows B and C opposite to each other around the rotating shafts 83 and 84, respectively, and the rotating shafts thereof are operated by the screw portions 85 and 86. The developer is conveyed in the direction, that is, the direction perpendicular to the paper surface in FIG. 2 in which the rotation shafts 83 and 84 extend.

  Specifically, the developer transport directions by the first transport screw 53 and the second transport screw 54 are respectively from the front side to the back side and from the back side to the front side in FIG. 2, and in FIG. The left-to-right direction and the right-to-left direction are opposite to each other. Further, the partition wall 81 is not disposed in portions corresponding to both end portions of the first conveying screw 53 and the second conveying screw 54. Therefore, the developer is conveyed so as to circulate in a certain direction as indicated by an arrow D in FIG. 5 by the rotation of the first conveying screw 53 and the second conveying screw 54, and is stirred in this process. Yes. The region where the developer is stirred and circulated by the rotation of the first transport screw 53 and the second transport screw 54 is referred to as a stirring transport region.

  In FIG. 5, reference numerals 65 and 66 denote gears provided in the developing device 8 for rotationally driving the first conveying screw 53 and the second conveying screw 54, respectively. The gears 65 and 66 are disposed outside the developing case 55 and are driven to rotate in opposite directions by a motor as a drive source (not shown) so as to rotate the rotation shafts 83 and 84. The drive of the motor is controlled by the control means.

  In the developing device 8 having such a configuration, the developer in the developing chamber 58 that is stirred by the first conveying screw 53 and the second conveying screw 54 and charged with toner is carried on the developing roller 51, The carrying amount is regulated by the developing blade 52. The layered developer that is regulated and has an appropriate amount on the developing roller 51 is carried to the developing region between the developing roller 51 and the photosensitive member 5 by the rotation of the developing roller 51 in the E direction, and is sufficiently charged. The toner in the developer is electrostatically transferred to an electrostatic latent image formed on the surface of the photoconductor 5, and the electrostatic latent image is visualized as a toner image.

  As described above, the developing device 8 performs development using a developer that is a two-component developer containing a black toner that is a non-magnetic toner and a magnetic carrier, but as the development is performed, the development is performed. The amount of toner in the agent is reduced. For this reason, toner is appropriately replenished from the replenisher cartridge 41 and the toner density of the developer circulating in the developing case 55 is maintained in a state suitable for development. For this purpose, feedback control using the toner density sensor 90 is performed. I do. Feedback control is performed using a control means.

  The toner density and the output voltage of the toner density sensor 90 exhibit substantially linear characteristics. When the toner density increases, the magnetic permeability decreases, the output voltage of the toner density sensor 90 decreases, and the toner density decreases. Then, the magnetic permeability is increased, and the output voltage of the toner concentration sensor 90 is increased. That is, the toner density is detected from the output of the toner density sensor 90.

  By utilizing such characteristics, when the output voltage of the toner concentration sensor 90 increases, it is detected that the toner concentration in the developer has decreased, that is, that the consumption of toner has progressed, and the replenisher is The toner is supplied from the replenisher cartridge 41 into the developing case 55. This control is performed by the control means.

  As shown in FIG. 2, the toner concentration sensor 90 agitates so that the detector 90 a of the toner concentration sensor 90 looks into the agitation chamber 59 so as to reliably detect the magnetic permeability of the developer. Arranged at the bottom of the chamber 59. In order to satisfactorily detect the toner concentration sensor 90, the developing device 8 is integrated with the second conveying screw 54 disposed in the stirring chamber 59 containing the developer detected by the toner concentration sensor 90. As shown in FIG. 2, a scraping member 67 that scrapes off the developer attached to the detection unit 90a of the toner density sensor 90 is provided.

  The scraping member 67 is a film-like resin sheet attached to the rotation shaft 84 of the second conveying screw 54 by adhesion, and has flexibility, each time the second conveying screw 54 makes one rotation. The detector 90a is touched and rubbed. The scraping member 67 may be attached with a tape.

  In order to prevent the screw portion 86 and the stirring chamber 59 from deteriorating due to friction with the developer accompanying the rotation of the screw portion 86, there are several millimeters between the screw portion 86 and the inner wall surface of the stirring chamber 59. Since the clearance is provided, the developer attached to the detection unit 90a is not completely wiped off by the screw part 86, and the developer attached to the detection unit 90a may remain without being stirred, By providing such a scraping member 67, the developer attached to the detection unit 90a is wiped off satisfactorily and agitation is also performed well.

  Thus, the toner concentration sensor 90 detects the toner concentration in the developer satisfactorily. In particular, since the position where the detection unit 90a of the toner concentration sensor 90 is disposed is the bottom of the stirring unit 59, which is a space where the scraping member 67 interferes with the developer, the toner concentration sensor 90 reliably and satisfactorily increases the toner concentration. Detect.

  Here, since the magnetic permeability of the developer fluctuates due to a change in the environment, a change in the bulk density of the developer, and the like, the output target value of the toner concentration sensor 90 is corrected as appropriate. Specifically, the output target value of the toner density sensor 90 is corrected according to the output result of the image density of the reference toner image formed on the photoconductor 5 measured using the image density sensor 18.

The replenisher supplied into the developing case 55 is stirred and mixed with the developer originally in the developing case 55 by the first conveying screw 53 and the second conveying screw 54.
Here, when the replenisher is appropriately supplied as described above, the toner concentration is maintained appropriately. However, when friction and collision between the toner and the carrier are repeated, a part of the toner adheres to the carrier. As a result, the carrier surface is contaminated, the carrier coat layer is peeled off or the like, and the carrier is deteriorated. The charging ability of the carrier with respect to the toner is gradually lowered, which causes the image quality to be remarkably lowered.

Therefore, when carrier deterioration occurs, it is necessary to replace the carrier to maintain the toner charging ability. The replacement of the carrier is sequentially performed when the developer overflows as the replenishment agent including the new carrier is replenished.
That is, when such replenishment is performed, the amount of the developer in the developing case 55 increases, and the upper part of the developer occupies a position higher than the lowest part of the developer discharge port 64, and this developer discharge port The developer occupying a position higher than the lowest part of 64 overflows from the developer discharge port 64, that is, overflows, passes through the developer discharge portion 49, and is then driven by the control means. The developer is transported in the developer transport path 48 by the developer transport screw 63 that is driven to rotate, and is collected in the developer collection container.

  As described above, the developing device 8 is configured such that the discharge is controlled according to the level of the developer in the developing case 55, that is, the height thereof. The discharged developer is discharged out of the developing case 55, whereby the carrier is exchanged.

  In the process of such feedback control, the replenisher supplied into the developing case 55 needs to be rapidly stirred and dispersed with the developer existing in the developing case 55. If the stirring and mixing is insufficient, the replenished toner is not sufficiently charged and may cause toner scattering. When toner scattering occurs, the inside of the image forming apparatus 100 is contaminated by the toner, and the photosensitive member. This is because 5 may be contaminated to cause an image defect. In addition, the toner may be subjected to development while being in an agglomerated state, thereby reducing the image quality.

  However, it is desirable that the stirring and mixing be performed by a mechanism that satisfactorily mixes while suppressing an increase in the size of the apparatus, and that the developer is deteriorated due to the mechanical load being applied to the developer by the stirring and mixing. In order to prevent this, it is necessary to suppress the mechanical burden on the developer during stirring and mixing.

  Therefore, in the developing device 8, the replenisher is replenished through the replenishing port 40 from below the stirring and conveying area. For this reason, the replenishing port 40 is disposed on the bottom surface of the developing case 55 below the stirring and conveying region and below the second conveying screw 54, and the replenisher is replenished from the bottom surface.

  Here, the bottom surface of the developing case 55 is the surfaces F and G depending on the partition wall 81 and the side wall 47 of the developing case 55 at the center of the wall thickness, as shown by hatching in FIG. When the intersecting lines with the horizontal plane H including the center of the wall thickness of the bottommost part 55 are I and J, respectively, the plane including the rotation center of the second conveying screw 54 and each of the intersecting lines I and J is a developing case. An area sandwiched by surfaces intersecting with 55.

  In this embodiment, the supply port 40 is formed at the bottom of the developing case 55. This is because the powder surface of the developer in the developing case 55, in other words, the distance to the surface is the largest, and stirring and mixing is performed satisfactorily. However, if the replenishing port 40 is formed on the bottom surface, Since stirring and mixing are ensured, as shown in FIG. 7, it may be formed in a portion other than the bottom. Note that the replenishing port 40 may be provided at a lower position in the direction of gravity than the surface of the developer, instead of the bottom, as long as the replenisher is stirred and mixed well.

  The replenishment agent is replenished from the replenishing port 40 disposed at such a position, and the replenishment agent is particularly in the agitating and conveying region, as shown in FIG. Therefore, the replenishing port 40 is arranged at the upstream portion of the bottom of the developing case 55 in the transport direction. It is installed. Here, the upstream portion refers to a portion on the upstream half of the stirring chamber 59 that substantially forms the stirring and transporting region in the transport direction, and is a position where stirring and mixing of the replenisher is sufficiently performed. Any portion may be used, but it is desirable that the portion is one third of the upstream side in consideration of stirring and mixing properties.

  The replenisher transport path 42, the replenisher replenishment unit 44, the replenisher transport screw, the replenisher transport motor 43, the pump 46, and the powder pump 50 stir and transport the replenisher through the refill port 40. Replenishing means for replenishing the upstream portion of the developer conveying direction by the second conveying screw 54 from below the region is configured. The powder pump 50 can be omitted as appropriate.

  In the developing device 8, the replenishing agent supplied into the developing case 55 through the replenishing port 40 by the replenishing means can move so as to slide on the surface of the developer unlike when replenished from above the developer. However, the developer is always in a state of being stirred and mixed, and the second conveying screw 54 performs stirring and mixing. In particular, since the airflow formed by the pump 46 is supplied from the replenishing port 40, the developer is loosened in the vicinity of the replenishing port 40 to increase the fluidity. In this state, the replenisher is brought into the developing case 55 together with the airflow. Since it is supplied, the stirring and mixing properties are extremely high. Further, since the replenisher is supplied into the developing case 55 by an air current, toner aggregation is unlikely to occur.

  Due to the synergistic effect of these actions, the replenisher is agitated and conveyed by the second conveying screw 54 and further agitated and conveyed by the first conveying screw 53. In this process, the replenisher is agitated and mixed with the developer very well, and the toner is also charged. Very well done. And since it will be uniformly disperse | distributed in a developing agent by the time it reaches the developing roller 51, problems, such as development nonuniformity, will not arise by such supply, but favorable development will be performed.

  Since the exhaust air is exhausted from the exhaust port 91 in response to the inflow of the airflow, the air pressure in the developing case 55 does not rise, and the air discharged from the exhaust port 91 is pumped again through the closed path as described above. Therefore, the developer is prevented from being ejected from between the developing case 55 and the developing roller 51, and the developer is not scattered outside. Accordingly, it is possible to reduce the maintenance time and frequency of service personnel due to contamination inside the image forming apparatus 100, and to reduce the time during which the image forming apparatus 100 cannot be used. High nature.

  Here, as shown in FIG. 4, the exhaust port 91 is the upper surface of the developing case 55, and the position of the supply port 40 is arranged so that the airflow flowing in from the supply port 40 performs the action of loosening the developer better. In other words, in the developer transport direction by the second transport screw 54, it is disposed at a downstream position, and a sufficient distance from the supply port 40 is taken. By disposing at this position, the replenishment agent replenished from the replenishing port 40 is also prevented from flowing out from the exhaust port 91 without being sufficiently mixed with the developer. In order to prevent the developer from flowing out from the exhaust port 91, a filter may be provided at the exhaust port 91.

  In order to further improve the stirring and mixing properties, the pump 46 and the replenisher transporting motor 43 are left after a long period of time, for example, when the developing device 8 starts up, such as when the image forming apparatus 100 is turned on or started up from the standby mode. Among them, it is desirable to drive only the pump 46 to supply only the air flow to the developing device 8 to quickly increase the fluidity of the developer in the developing device 8 and to eliminate the state where the bulk density is increased.

  As described above, the flowability of the developer affects the stirring and mixing properties of the replenisher. Therefore, in order to maintain the flowability of the developer, the drive of the pump 46 is controlled according to the flowability of the developer. Is desirable. Therefore, a pressure gauge can be provided in or near the replenishing port 40, and the control means can control the driving of the pump 46 in accordance with the flowability of the developer indicated by the output value of the pressure gauge. Such a drive control mode includes controlling the amount of airflow generated by the pump 46. By performing such control, even when the developer deteriorates with time and the bulk density changes, the flowability of the developer is maintained, and the stirring and mixing property of the replenisher is maintained.

If the flow rate of the air flow with respect to the amount of the replenishing agent is increased, the stirring and mixing property is further increased. Therefore, as shown in FIG. 8, the pump 46 is always driven and the replenisher transporting motor 43 is intermittently driven to Always flows into the developing case 55 and the replenisher is intermittently supplied in small amounts. These effects are the advantages of improving the detection accuracy of the toner density sensor 90 as well as reducing the stress on the developer, suppressing the deterioration of the developer, stabilizing the chargeability and image quality by improving the dispersibility as described above. There is also. In addition, since the toner density is made uniform in a short time, the time required for controlling the toner density is shortened. If these can be achieved, the pump 46 may be driven intermittently as appropriate.

  Further, by constantly driving the pump 46, the developer is clogged in the replenishing port 40 and the replenisher transport path 42 without providing a member for opening and closing the replenishing port 40, and the developer is replenished in the replenishing port 40 and the replenisher transport path Backflow and retention in 42 are prevented and replenishment of the replenisher is performed well whenever desired.

  The flow rate of air from the pump 46 is preferably 0.1 l / min to 2.0 l / min, and in this embodiment, 0.5 l / min to 1.0 l / min. This is because if the flow rate is too small, the replenisher is not conveyed and clogs in the replenisher transport path 42, and if the flow rate is too high, the replenisher may penetrate the developer in the developing case 55 due to the force of the airflow. It is because there is sex. The flow rate is appropriately adjusted depending on the size of the developing case 55, the amount of developer inside, and the fluidity of the developer.

As a configuration for preventing clogging, backflow, and stagnation of the developer, in the developing device 8, the replenishment direction of the replenisher from the replenishing port 40 to the stirring and transporting region is inclined with respect to the developer transporting and transporting direction. A configuration that is not parallel to the direction is adopted. As shown in FIG. 4 and FIG. 9A, this configuration in the present embodiment includes a first portion 42 a in which a replenisher transport path 42 is connected to the replenishing port 40 with an inclination from below, And a second portion 42b connected to the first portion 42a from a direction that is not parallel to the direction in which the portion 42a is formed, specifically, a direction that forms a wide angle.
According to such a configuration, in particular, the first portion 42a is inclined and connected obliquely at the replenishing port 40, so that clogging, backflow, and retention are well prevented. Further, the same function can be obtained when the second portion 42b is inclined with respect to the first portion 42a.

  As shown in FIG. 9B, the first portion 42 a may be connected vertically at the supply port 40 in order to obtain a similar function. Further, as shown in FIG. 9B, in order to obtain the same function, the second portion 42b may be connected perpendicularly to the first portion 42a. Further, if the same function can be obtained, the replenishment agent transport path 42 may be configured only by the first portion 42 a that is vertically connected to the replenishment port 40. The first part 42a and the second part 42b are not in a clearly distinguishable shape, and the replenisher transport path 42 may have a gently curved shape as shown in FIG.

As shown in FIG. 10, an opening / closing member that opens and closes the replenishing port 40 may be provided as a configuration for preventing clogging, backflow, and retention of the developer.
The opening / closing member 56 shown in FIG. 10A is a shutter member 56 that moves in parallel with the developer transport direction and opens and closes the supply port 40 by sliding. The opening / closing member 57 shown in FIG. This is a push-open type swing shutter that opens and closes the supply port 40 by swinging about the shaft 57a.

  The opening / closing members 56 and 57 are driven by the control means so as to open the supply port 40 only when the supply agent is to be supplied from the supply port 40. However, the supply port 40 may be opened when the pump 46 is operated, even if the supply agent is not supplied. Instead of being driven to open and close by the control means, it may be configured to open by the pressure of the airflow.

Since the opening / closing member 56 slides in a direction parallel to the developer conveyance direction, the driving load is small.
Since the opening / closing member 57 opens the replenishing port 40 in a direction toward the downstream side in the developer transport direction, the inflow of the developer into the replenishing port 40 is effectively prevented. In this case, since the opening / closing member 57 opens toward the inside of the developing case 55 and the tip is close to the second conveying screw 54, in order to prevent contact with the second conveying screw 54, a position directly above the supply port 40. The diameter of the screw portion 86 is smaller than that of the other portions, and is configured to prevent contact with the opening / closing member 57.

  Although the developing device 8 having the pump 46 has been described above, the developer amount in the developing case 55 is 200 g, and the second conveying screw 54 having a rotating shaft 84 having a shaft diameter of 5 mm and a screw portion 86 having an outer diameter of 12 mm is provided. In this embodiment in which the average particle diameter of the toner and the carrier is 6 μm and the air flow rate is 0.5 l / min to 1.0 / min, the replenisher can be mixed and stirred well in a conventional developing device. The above-mentioned functions, actions and effects were exhibited well.

  The powder pump 50 can be omitted as appropriate. As shown in FIG. 11, a suction-type powder pump 70 as an airflow forming unit may be provided instead of the discharge-type powder pump 50. The powder pump 70 is disposed in the middle of a replenisher transfer path 42 ′ connected to the replenisher transport path 42. In such a configuration, the replenisher transport path 42 can be freely routed as described below, and the arrangement position of the replenisher cartridge 41 can be freely selected. Since “the replenisher in the inside” is also conveyed by the pressure of the powder pump 70, the replenisher transfer path 42 ′ can be freely arranged. The image forming apparatus can be disposed at a position far from 55 and can be disposed at a position that does not interfere with each other, and there is an advantage that the degree of freedom in layout of the developing device 8 and the image forming apparatus 100 is increased. In the configuration example shown in FIG. 11, the replenisher transport motor 43 is omitted. Thus, the replenisher transport motor 43 can be omitted as appropriate.

  In the configuration example shown in FIG. 11, the replenisher transport path 42 and the replenisher transport path 42 'have an inner diameter of about 3 to 7 mm, are flexible and have excellent toner resistance, and rubber materials such as polyurethane, nitrile, EPDM, and silicon. Or a plastic material such as polyethylene or nylon. Therefore, it is possible to freely distribute the replenisher transporting path 42, the disposition position of the replenisher cartridge 41 can be freely selected, and it can be disposed at the least disturbing position. 8. There is an advantage that the degree of freedom of layout of the image forming apparatus 100 is increased. Even if the replenisher transport path 42 is freely arranged, the replenisher is favorably conveyed through the replenisher transport path 42 and supplied into the developing case 55 by the pressure of the pump 46. The lower the degree of aggregation of the toner, the higher the fluidity of the replenisher, and the above-mentioned functions, functions, and effects can be obtained. Even if the aggregation degree is changed to 10 to 80 among the above-mentioned conditions, stirring and mixing are performed. The properties, functions, and effects described above were obtained.

  FIG. 12 and subsequent figures show a developing device 8 that includes a replenisher transporting member for replenishing a replenisher from the replenishing port 40 in place of the pump 46 or together with the pump 46, thereby constituting a replenishing means. In the following description, the same components as those of the developing device 8 described above are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  The developing device 8 shown in FIGS. 12 to 14 has augers 71 and 72 as toner conveying augers as a replenisher conveying member instead of the pump 46, and these are driven by a replenisher transport motor 43. It is supposed to be. That is, the developing device 8 includes a replenisher transport motor 43, a gear 73 that is rotationally driven by the replenisher transport motor 43, an auger 71 that has the gear 73 at one end and is rotationally driven integrally with the gear 73, A bevel gear 74 disposed on the other end of the auger 71 and rotated integrally with the auger 71; a bevel gear 75 that meshes with the bevel gear 74 and is driven to rotate by the bevel gear 74; It has a bevel gear 75 at one end and an auger 72 that is rotationally driven integrally with the bevel gear 75. The exhaust part 45 is not provided.

  Each auger 71 and 72 has a screw shape, and conveys the replenisher in a certain direction by rotating in a certain direction. The driving of the replenisher transport motor 43 is controlled by the control means, and by rotation drive, the auger 71 is rotationally driven by the gear 73 in the predetermined direction, and the auger 72 is further driven by the bevel gears 74 and 75 in the predetermined direction. Rotating drive.

  Accordingly, the auger 71 conveys the replenisher sent from the replenisher cartridge 41 by the replenisher transport motor 43 in the left direction in FIG. 14 in the replenisher transport path 42, and the auger 72 is transported by the auger 71. The supplied replenisher is transported so as to be lifted upward in FIG. 14 in the replenisher transport path 42, and the replenisher is replenished from below the stirring and transporting region through the replenishment port 40. This replenishment operation is performed by the feedback control described above.

  In this embodiment, in the configuration in which the auger 72 is provided, the auger 72 has a shape that closes the supply port 40. As a result, the screw portion of the auger 72 serves as a lid for the replenishment port 40, the developer in the developing case 55 does not flow into the replenisher transport path 42, and the replenishment agent is not replenished. Is prevented from blocking the replenishing port 40 and the replenisher transporting path 42, and clogging, backflow and stagnation of the developer are prevented in the same manner as in the configuration shown in FIGS. In order to do this well, the auger 72 is driven in the same manner as the drive timing of the pump 46 described above.

  In order to perform this more satisfactorily, as shown in FIGS. 15 (a) and 15 (b), the diameter d1 of the replenishing port 40 is a circular shape having substantially the same diameter as the outer diameter d2 of the screw portion of the auger 72. It is desirable. In order to prevent such clogging, backflow, and stagnation, at least the diameter d1 of the replenishing port 40 should be the same diameter as d2, and only the diameter of the replenishing port 40 is applied as shown in FIG. The diameter of the replenisher transport path 42 connected to the replenishing port 40 may be larger than d2, and not only the diameter of the replenishing port 40 but also the replenishing port 40 as shown in FIG. The diameter of the replenisher transporting path 42 in the portion thus formed may be substantially the same as d2.

  On the other hand, as shown in FIG. 15C, when the diameter d1 is larger than the diameter d2, such clogging, backflow, and retention may occur. However, the size of the developer particles, the shape of the surface, By appropriately setting the size of the gap in consideration of characteristics such as activity, it is possible to prevent such clogging, backflow, and retention.

  As shown in FIG. 16, a powder pump 70 may be provided instead of the auger 71. The auger 72 is rotationally driven by a gear 73 disposed at one end thereof. The gear 73 is rotationally driven by a replenisher transport motor 43. To supply the replenisher, the powder pump 70 is driven by the control means to transport the replenisher in the replenisher cartridge 41 and the replenisher transport motor 43 is driven to replenish the replenishment that has been transported by the powder pump 70. This is performed by performing the above-described feedback control in a mode in which the agent is supplied into the developing case 55 from the supply port 40. The driving timing of the auger 72 is the same as described above. The exhaust part 45 is disposed as necessary.

  As shown in FIG. 17, a pump 46 may be provided instead of the auger 71, and the pump 46 and the auger 72 may be combined. The pump 46 is connected to the replenisher transport path 42 via the tube 76, and an air flow is caused to flow into the replenisher transport path 42 via the tube 76, so that the replenisher transported in the replenisher transport path 42 is supplied. The auger 72 supplies the toner to the developing case 55 through the supply port 40.

  The material of the tube 76 is the same as that of the replenisher transport path 42 and the replenisher transport path 42 'shown in FIG. 11, but the inner diameter is about 2 to 7 mm. Therefore, the arrangement position of the pump 46 can be freely selected, can be arranged at the position that does not interfere with each other, and the degree of freedom in layout of the developing device 8 and the image forming apparatus 100 is increased in FIG. This is the same as the example shown. The exhaust part 45 is provided.

  To supply the replenisher, the pump 46 is driven by the control means to transport the replenisher in the replenisher cartridge 41 and the replenisher transport motor 43 is driven to supply the replenisher transported by the pump 46 to the supply port. This is performed by performing the above-described feedback control under a mode in which the toner is supplied from 40 into the developing case 55. The driving timing of the auger 72 is the same as described above.

In the configuration provided with these augers 72, it is not necessary to provide the above-mentioned opening / closing member, and in the example shown in FIGS. 16 and 17, only one auger 72 is sufficient.
In the configuration including the powder pump 70 and the pump 46, the operation timing is the same as in the example shown in FIG. 3, so that clogging, backflow, and stagnation of the developer due to the airflow can be prevented. . In this case, even if the outer diameter of the auger 72 is the same as that shown in FIG.

  As described above, the developing device, the image forming apparatus, and the image forming method to which the present invention is applied have been described as embodiments for carrying out the present invention. However, the application of the present invention is not particularly limited in the above description. It is not restricted to the above-mentioned form. For example, the stirring and conveying member may have a paddle shape instead of a screw shape.

1 is a schematic front view of an image forming apparatus to which the present invention is applied. FIG. 2 is a schematic front view of a part of a developing device provided in the image forming apparatus shown in FIG. 1. FIG. 2 is a perspective view of a part of a developing device provided in the image forming apparatus shown in FIG. 1. FIG. 2 is a side sectional view of a developing device provided in the image forming apparatus illustrated in FIG. 1. FIG. 2 is a schematic plan view of a part of a developing device provided in the image forming apparatus shown in FIG. 1. FIG. 3 is a schematic front view for explaining the arrangement position of a replenishing port, which is a part of the developing device shown in FIG. 2. FIG. 7 is a schematic front view showing different arrangement positions of supply ports in the developing device shown in FIG. 6. 3 is a timing chart showing the relationship between the operation timing of the air flow forming means and the replenishment agent replenishment timing in the developing device shown in FIG. 2. FIG. 3 is a schematic diagram illustrating various configurations of a developer transport path in the developing device illustrated in FIG. 2. FIG. 3 is a schematic diagram showing an arrangement mode when an opening / closing member for opening and closing a replenishing port is arranged in the developing device shown in FIG. 2. FIG. 5 is a side sectional view of a developing device having another configuration provided in the image forming apparatus illustrated in FIG. 1. FIG. 7 is a perspective view of a part of a developing device having still another configuration provided in the image forming apparatus shown in FIG. 1. FIG. 13 is a schematic front view of a part of the developing device shown in FIG. 12. FIG. 13 is a side sectional view of a part of the developing device shown in FIG. 12. It is a schematic diagram which shows the combination of the various structure aspects of the replenishment agent conveyance member with which the image development apparatus shown in FIG. FIG. 14 is a side sectional view of still another configuration of the developing device shown in FIG. 12. FIG. 13 is a schematic diagram of still another configuration of the developing device illustrated in FIG. 12.

Explanation of symbols

8 Developing device 40 Supply port 42 Transport path 42 to 44, 46, 50 Supply unit 42, 42 ', 43, 44, 46, 70 Supply unit 42 to 44, 71 to 75 Supply unit 42 to 44, 70, 72, 73 Supply means 42-44, 46, 72, 73, 76 Supply means 42a First part 42b Second part 46 Airflow forming means 50 Airflow forming means 53, 54 Stirring conveying member 56 Opening / closing member 57 Opening / closing member 70 Airflow forming means 71 72 Supply agent conveying member 91 Exhaust port 100 Image forming apparatus

Claims (12)

A stirring and conveying member that conveys a developer containing toner and a carrier while stirring;
Replenishment means for replenishing the developer agitating and conveying area by the agitating and conveying member with a replenisher containing at least one of toner and carrier;
A replenishment port for replenishing the agitation transport area with the replenishment means,
The replenishing means is a developing device that replenishes the replenishment agent through the replenishment port from below the agitation conveyance region to the upstream side portion in the developer conveyance direction by the agitation conveyance member ,
A push-opening opening / closing member that opens the replenishing port in a direction toward the downstream side in the transport direction;
The replenishing means has airflow forming means for forming an airflow for replenishing the replenisher from the replenishing port;
A developing device that pushes the opening / closing member open by the air flow formed by the air flow forming means, opens the replenishing port in the direction, and replenishes the replenisher from the replenishing port . The developing device according to claim 1, wherein a replenishing direction of the replenisher from the replenishing port to the stirring and transporting region is non-parallel to the transporting direction . 3. The developing device according to claim 1 , further comprising an exhaust port for exhausting the airflow formed by the airflow forming unit.   4. The developing device according to claim 3, wherein the air flow path by the air flow forming means is a closed path passing through the replenishing port and the exhaust port. 5. The developing device according to claim 1 , wherein only the airflow is supplied by the airflow forming unit when the apparatus is started up. 6. The developing device according to claim 1 , wherein an air flow is constantly supplied by the air flow forming unit. 7. The developing device according to claim 1 , further comprising a control unit configured to control an amount of airflow formed by the airflow forming unit in accordance with fluidity of the developer replenished with the replenisher. A developing device.   8. The developing device according to claim 1, wherein the replenishing means has a replenisher transport member for replenishing the replenisher from the replenishing port.   The developing device according to claim 8, wherein the replenisher transport member has a shape that closes the replenishing port. 10. The developing device according to claim 1, wherein a first portion connected to the supply port from below and a direction non-parallel to a direction in which the first portion is formed change from the first portion to the first portion. And a second path connected to the replenishing means, wherein the replenishing means transports the replenisher . An image forming apparatus comprising the developing device according to claim 1 . The developing device according to any one of claims 1 to 10, or an image forming method for forming an image by using an image forming apparatus according to claim 11, wherein.

Images