JP2010152109A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device which allows a long life of developer and allows a developer to be sufficiently mixed and agitated. <P>SOLUTION: The developing device includes: an agitating-and-conveying section storing developer and having a mixing-and-agitating member for conveying the developer while mixing and agitating the developer; a developer carrier that is disposed opposite to an electrostatic latent image carrier bearing an electrostatic latent image, bears developer, mixed and conveyed by the agitating-and-conveying member, on its periphery, and supplies it to the electrostatic latent image carrier; and a storage section 140 that temporarily stores developer and includes an agitating-and-conveying member 141 in it. Communicating parts 147 and 148 by which the storage section 140 and the agitating-and-conveying section communicate are provided upstream and downstream of the agitating-and-conveying section in the direction of developer conveyance. The communicating parts 147 and 148 are provided with removable sealing members that temporarily seal the communicating parts. The agitating-and-conveying section includes a staying section in a position corresponding to the communicating part 147, which is disposed downstream of the agitating-and-conveying section in the direction of developer conveyance, the staying section being used to cause developer to stay. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developing device and an image forming apparatus.

  2. Description of the Related Art Conventionally, a developing device that develops an electrostatic latent image formed on the surface of a photosensitive drum as an image carrier using a two-component developer composed of a toner and a carrier has been used. A developing device using a two-component developer includes a stirring and conveying unit that mixes and stirs the developer and supplies the developer to the developing roller, and a developing roller that supplies toner to the electrostatic latent image on the photosensitive drum. . The agitating / conveying unit mixes the carrier, which is a magnetic material, and the non-magnetic or weakly magnetic toner so as to be uniform, and stirs the toner so that the toner is frictionally charged. The developer mixed and agitated by the agitating and conveying unit is conveyed through a conveying path in the agitating and conveying unit and is supplied to the developing roller. The developing roller carries a part of the toner flowing through the conveyance path and provides the toner to the electrostatic latent image on the photosensitive drum.

  Such a developing device is provided with a storage space for temporarily storing the developer during transport of the developing device in order to prevent leakage and spillage of the developer filled in the device during transport. The storage space is provided so as to be able to communicate with the agitation transport unit through the communication unit. When the developing device is transported, the storage space and the agitation transport unit are sealed with a seal member so as not to communicate with each other. When the developing device is attached to the image forming apparatus, the seal member is removed, whereby the storage space and the agitation transport unit are communicated with each other, and the developer provided in the storage space flows into the agitation transport unit.

  In the developing device using the two-component developer, there is a problem in that the carrier circulating in the developing device deteriorates with time due to stirring, resulting in a reduction in image quality. In order to solve such a problem, a technique for extending the life of the developer has been proposed. For example, Patent Documents 1 and 2 propose a developing device having a mechanism for mechanically or electrically discharging a deteriorated developer while supplying a carrier as well as supplying toner.

JP 2000-81787 A JP 2003-345132 A

  In recent years, with the miniaturization of printers and the like, there has been a demand for miniaturization of developing devices. However, as described above, the developing device is provided with a developer storage space that is used only when the developing device is transported. After the seal member provided in the communicating part with the agitating / conveying part was removed and the developer in the storage space flowed into the agitating / conveying part, the storage space did not function at all and was a useless space. If a storage space is not provided in the developing device, a sealing member must be provided between the developing roller and the developer transport path, etc., and it is difficult to attach the sealing member, and there is a concern about its sealing performance. was there.

  As for the developer life extension technology, as in Patent Documents 1 and 2, a developing device has a mechanism for mechanically or electrically discharging the deteriorated developer while supplying the carrier as well as supplying the toner. Can also be prepared. However, when the developer is mechanically discharged, a mechanism for that purpose is required separately. In addition, when the developer is discharged electrically, for example, the carrier can be developed on the photosensitive drum on which image formation is performed and the carrier can be collected by a cleaner. In addition, the photoconductor drum is damaged and the image quality is deteriorated. Furthermore, when the developer is discharged mechanically or electrically, a recovery tank for storing the discharged developer and a means for transporting the discharged developer to the recovery tank are required, and the space is further reduced. There was a problem that it led to a significant cost increase.

  Furthermore, with the downsizing of the developing device, the agitation transport unit is usually provided with two agitation transport members. However, the step of mixing and stirring the replenished toner is performed by only one of the two stirring and conveying members, and there is a problem that it is difficult to sufficiently stir and convey the developer.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is a novel and improved technique capable of extending the life of the developer and sufficiently mixing and stirring the developer. Another object of the present invention is to provide a developed developing device and an image forming apparatus.

  In order to solve the above-described problems, according to one aspect of the present invention, an agitating and conveying unit having a mixing and agitating member that contains a developer composed of a carrier and toner, mixes and agitates the developer, and conveys the developer in a predetermined conveying direction. And a developer that is provided opposite to the electrostatic latent image carrier that carries the electrostatic latent image and that supports the developer stirred and conveyed by the agitating and conveying unit on the peripheral surface and supplies the developer to the electrostatic latent image carrier. A carrier, a storage unit that temporarily stores developer, mixes and agitates the developer and conveys the developer in a predetermined conveyance direction, and a storage unit therein, and replenishes developer according to the amount of toner used And a developer supply unit. On the upstream side and downstream side in the developer conveying direction of the agitating / conveying unit, there are respectively provided communicating parts that connect the storage part and the agitating / conveying part, and the communicating parts are temporarily removed from the communicating part. Possible sealing members are provided. The agitation transport unit is provided with a staying part for retaining the developer at a position corresponding to a communication part provided downstream in the developer transport direction in the agitation transport unit.

  According to the present invention, when the seal member provided in the communication portion is removed, the developer stored in the storage portion flows into the stirring and conveying portion. The developer that has flowed into the agitation conveyance unit is conveyed in a predetermined conveyance direction while being mixed and agitated in the agitation conveyance unit, and is supplied to the developer carrier. On the other hand, the stirrer / conveyor provided at a position corresponding to the communicating part where the stirrer / conveyor communicates with the storage unit is provided with a staying part for retaining the developer. The developer transport speed by the stirring and transporting member of the stirring and transporting unit is lowered by the staying unit, so that the staying developer easily flows into the storage unit. The developer that has flowed into the storage unit is transported in a predetermined transport direction while being mixed and stirred by a stirring transport member provided in the storage unit, and flows from the other communication unit to the stirring transport unit. As described above, the developer can be sufficiently mixed and stirred by using the storage portion that temporarily stores the developer as a part of the conveyance path for mixing and stirring the developer.

  Further, according to the amount of toner used in the developing device, the developer is supplied from the developer supply unit into the developing unit. The developing device of the present invention is not provided with a mechanism for recovering the deteriorated developer, and only the developer is supplied. For this reason, it is possible to reduce the deterioration rate with respect to the deterioration of the developer accompanying the image forming operation, and as a result, it is possible to extend the life of the developer.

  Here, the stirring and conveying unit is configured to include at least two stirring and conveying members. At this time, the developer conveyance directions of the agitation conveyance member provided in the agitation conveyance unit facing the developer carrier and the agitation conveyance member provided in the storage unit are the same. Accordingly, it is possible to prevent a large amount of developer from flowing into the agitation transport unit facing the developer carrying member, and the developer forms a flow of developer that circulates in the agitation transport unit and the storage unit. be able to.

  In addition, the agitating / conveying member provided in the agitating / conveying unit and the storage unit extends in the developer conveying direction, and is provided on the outer peripheral surface of the supporting shaft that is rotatably provided, and mixes the developer. And a stirring blade that is conveyed while stirring. At this time, the staying portion is provided on the downstream side in the developer conveyance direction of the agitation conveyance member provided in the agitation conveyance unit facing the storage unit. By providing the staying portion on the downstream side in the developer transport direction of the stirring and transporting member of the stirring and transporting portion facing the storage portion, the developer stays in the vicinity of the communicating portion between the stirring and transporting portion and the storage portion. As a result, the developer easily flows not only into the stirring and conveying unit side facing the developer carrying member but also into the storage unit side.

  The stirring / conveying member provided with the staying portion may be formed, for example, such that the shaft diameter of the support shaft located at the staying portion is larger than the shaft diameter of the support shaft at other positions, and the stirring blade located at the staying portion. May be removed. Alternatively, the stirring / conveying member provided with the staying portion may be formed such that the outer diameter of the stirring blade located in the staying portion is smaller than the outer diameter of the stirring blade in another position, and the stirring blade located in the staying portion. In addition, a paddle for connecting between adjacent stirring blades may be provided. Further, the stirring and conveying member provided with the staying portion is formed so that the pitch representing the interval between the stirring blades adjacent to each other in the support shaft direction of the stirring blade located in the staying portion is smaller than the pitch of the stirring blades at other positions. May be. The developer can be retained by forming the agitating / conveying member provided in the agitating / conveying unit facing the storage unit in this manner and providing the retaining part.

  In order to solve the above problems, according to another aspect of the present invention, an electrostatic latent image carrier that carries an electrostatic latent image on a peripheral surface, and an electrostatic latent image on the electrostatic latent image carrier. An image forming apparatus is provided. The developing device is provided so as to face the electrostatic latent image carrier, and a stirrer / conveyor having a mixing and agitating member that contains a developer composed of a carrier and toner, mixes and stirs the developer and conveys the developer in a predetermined conveying direction. A developer carrying body that is carried on the circumferential surface by the developer carried by the stirring and carrying section and that is supplied to the electrostatic latent image carrying body, and the developer is temporarily stored, and the developer is mixed and stirred. A storage unit having an agitating and conveying member for conveying in a predetermined conveying direction and a developer replenishing unit for replenishing the developer according to the amount of developer used are provided. On the upstream side and downstream side in the developer conveying direction of the agitating / conveying unit, there are respectively provided communicating parts that connect the storage part and the agitating / conveying part, and the communicating parts are temporarily removed from the communicating part. Possible sealing members are provided. The agitation transport unit is provided with a staying part for retaining the developer at a position corresponding to a communication part provided downstream in the developer transport direction in the agitation transport unit.

  As described above, according to the present invention, it is possible to provide a developing device and an image forming apparatus capable of extending the life of the developer and sufficiently mixing and stirring the developer.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  First, a schematic configuration of an image forming apparatus 1 including a developing unit 100 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is an explanatory diagram showing a schematic configuration of the image forming apparatus 1 according to the present embodiment.

<Schematic configuration of image forming apparatus>
The developing unit 100 according to this embodiment can be provided, for example, in a tandem image forming apparatus as shown in FIG. As shown in FIG. 1, the image forming apparatus 1 includes a recording medium conveyance unit 10, a transfer unit including a transfer belt 20 as an intermediate transfer member, a photosensitive drum 30 that carries an electrostatic latent image, and a photosensitive drum 30. The image forming apparatus includes a developing unit 100 that develops the electrostatic latent image formed thereon, and a fixing unit 40.

  The recording medium conveyance unit 10 accommodates a recording medium on which an image is finally formed and conveys the recording medium onto the recording medium conveyance path. The recording medium is, for example, paper P and is stacked and accommodated in a cassette. The recording medium transport unit 10 causes the paper P to reach the secondary transfer area at the timing when the toner image to be transferred to the paper P is formed and reaches the secondary transfer area.

  The transfer unit conveys a toner image formed by a developing unit 100, which will be described later, to a secondary transfer region where the toner image is secondarily transferred to a recording medium. The transfer unit includes a transfer belt 20, suspension rollers 20a, 20b, 20c, and 20d that suspend the transfer belt 20, a primary transfer roller 22 that sandwiches the transfer belt 20 together with the photosensitive drum 30, and the transfer belt 20 together with the suspension roller 20d. The secondary transfer roller 24 sandwiches the toner.

  The transfer belt 20 is an endless belt that is circulated and moved by suspension rollers 20a, 20b, 20c, and 20d. The primary transfer roller 22 is provided so as to press the photosensitive drum 30 from the inner peripheral side of the transfer belt 20. On the other hand, the secondary transfer roller 24 is provided so as to press the suspension roller 20 d from the outer peripheral side of the transfer belt 20. Although not shown in FIG. 1, the transfer unit may further include a belt cleaning device that removes toner attached to the transfer belt 20.

  The photosensitive drum 30 is an electrostatic latent image carrier on which an image is formed on a peripheral surface, and is made of, for example, OPC (Organic PhotoConductor). The image forming apparatus 1 according to the present embodiment is an apparatus capable of forming a color image. For example, four photosensitive drums 30 are arranged in the rotation direction of the transfer belt 20 corresponding to each color of magenta, yellow, cyan, and black. Is provided. As shown in FIG. 1, a charging roller 32, an exposure unit 34, a developing unit 100, and a cleaning unit 38 are provided on the circumference of each photosensitive drum 30.

  The charging roller 32 uniformly charges the surface of the photosensitive drum 30 to a predetermined potential. The exposure unit 34 performs exposure according to an image forming the surface of the photosensitive drum 30 charged by the charging roller 32. As a result, the potential of the portion of the surface of the photosensitive drum 30 exposed by the exposure unit 34 changes, and an electrostatic latent image is formed. The developing unit 100 develops the electrostatic latent image formed on the photosensitive drum 30 with the toner supplied from the toner tank 36 (36M, 36Y, 36C, 36B), and generates a toner image. The detailed configuration of the developing unit 100 will be described later.

  The cleaning unit 38 collects the toner remaining on the photosensitive drum 30 after the toner image formed on the photosensitive drum 30 is primarily transferred to the transfer belt 20. The cleaning unit 38 may be configured to remove, for example, a residual blade on the photosensitive drum 30 by providing a cleaning blade and bringing the cleaning blade into contact with the peripheral surface of the photosensitive drum 30. A neutralizing lamp (not shown) for resetting the potential of the photosensitive drum 30 is provided between the cleaning unit 38 and the charging roller 32 in the rotation direction of the photosensitive drum 30 on the circumference of the photosensitive drum 30. It can also be arranged.

  The fixing unit 40 adheres and fixes the toner image secondarily transferred from the transfer belt 20 to the recording medium. The fixing unit 40 includes, for example, a heating roller 42 and a pressure roller 44. The heating roller 42 is a cylindrical member that can rotate around a rotation axis, and a heat source such as a halogen lamp is provided therein. The pressure roller 44 is a cylindrical member that can rotate around the rotation axis, and is provided so as to press the heating roller 42. A heat-resistant elastic layer such as silicon rubber is provided on the outer peripheral surfaces of the heating roller 42 and the pressure roller 44. By passing the recording medium through a fixing nip that is a contact area between the heating roller 42 and the pressure roller 44, the toner image is melted and fixed on the recording medium.

  Further, the image forming apparatus 1 is provided with discharge rollers 52 and 54 for discharging the recording medium on which the toner image is fixed by the fixing unit 40 to the outside of the apparatus.

  In such an image forming apparatus 1, first, when the image forming apparatus 1 is operated, an image signal of a recorded image is transmitted to a control unit (not shown). Next, the control unit uniformly charges the surface of the photosensitive drum 30 to a predetermined potential by the charging roller 32 based on the received image signal, and then emits laser light to the surface of the photosensitive drum 30 by the exposure unit 34. Irradiate to form an electrostatic latent image.

  On the other hand, in the developing unit 100, the toner and the carrier are mixed and stirred to be sufficiently charged, and then the developer is carried on the developing roller (reference numeral 110 in FIG. 1). When the developer is transported to a region facing the photosensitive drum 30 by the rotation of the developing roller 110, toner is formed on the peripheral surface of the photosensitive drum 30 among the developer carried on the developing roller 110. Move to the electrostatic latent image and develop the electrostatic latent image. The toner image thus formed is primarily transferred from the photosensitive drum 30 to the transfer belt 20 in a region where the photosensitive drum 30 and the transfer belt 20 face each other. On the transfer belt 20, toner images formed on the four photosensitive drums 30 are sequentially stacked to form one stacked toner image. The laminated toner image is secondarily transferred to the recording medium conveyed from the recording medium conveyance unit 10 in the area where the suspension roller 20d and the secondary transfer roller 24 are in contact with each other.

  The recording medium on which the laminated toner image is secondarily transferred is conveyed to the fixing unit 40. By passing the recording medium between the heating roller 42 and the pressure roller 44 while applying heat and pressure, the laminated toner image is melted and fixed on the recording medium. Thereafter, the recording medium is discharged to the outside of the image forming apparatus 1 by the discharge rollers 52 and 54. On the other hand, when the transfer belt 20 includes a belt cleaning device, the toner remaining on the transfer belt 20 is removed by the belt cleaning device after the laminated toner image is secondarily transferred to the recording medium.

  The tandem image forming apparatus 1 shown in FIG. 1 is an example of an image forming apparatus that uses the developing device 100 according to the present embodiment. The developing device 100 according to the present embodiment can use various types of image forming apparatuses. It can be applied to a forming apparatus.

  The schematic configuration of the image forming apparatus 1 including the developing unit 100 according to the present embodiment has been described above. The developing unit 100 according to the present embodiment realizes a long life of the developer and allows the developer to be sufficiently mixed and stirred. Therefore, the configuration and operation of the developing unit 100 according to the present embodiment will be described below with reference to FIGS. FIG. 2 is an explanatory diagram showing the configuration of the developing unit 100 according to the present embodiment. FIG. 3 is an explanatory diagram for explaining the flow of the developer in the developing unit 100 according to the present embodiment. In addition, in the left figure of FIG. 3, description of the partition wall between the 1st stirring conveyance part 120 and the 2nd stirring conveyance part 130 was abbreviate | omitted. The partition wall is provided so that the first agitation transport unit 120 and the second agitation transport unit 130 communicate with each other at both ends of each agitation transport unit.

<Configuration of development unit>
First, the configuration of the developing unit 100 according to the present embodiment will be described with reference to FIG. As shown in FIG. 2, the developing unit 100 according to the present embodiment includes a developing roller 110, stirring and conveying units 120 and 130, and a storage unit 140.

  The developing roller 110 is a developer carrier that supplies toner to the electrostatic latent image formed on the peripheral surface of the photosensitive drum 30. The developing roller 110 includes, for example, a developing sleeve 114 and a magnet 112 disposed inside the developing sleeve 114. The developing sleeve 114 is a cylindrical member made of a nonmagnetic metal. In the developing roller 110, only the developing sleeve 114 rotates, and the magnet 112 disposed in the developing sleeve 114 is fixed to the housing 5. Further, the developing roller 110 is provided with a developing bias applying unit (not shown) for applying a developing bias.

  The magnet 112 has a plurality of magnetic poles. For example, the magnet 112 has a region facing the photoconductor drum 30, that is, a region where an electrostatic latent image formed on the photoconductor drum 30 is developed, and from the development region to the stirring and conveying unit 120. Different magnetic poles can be alternately arranged up to the opposite position. This is because the developer is conveyed on the developing sleeve 114 by a magnetic force. Further, in the developing area, the magnetic brush of the developer is raised, and the magnetic brush is brought into contact with or close to the electrostatic latent image on the photosensitive drum 30, so that a pole position or a gap is arranged in the developing area. You can also. On the other hand, magnetic poles having the same polarity are arranged adjacent to each other in the circumferential direction at a position where the developing roller 110 corresponds to the stirring and conveying unit 120. The magnetic poles of the same polarity reduce the magnetic force in the tangential direction and the normal direction with respect to the rotation direction of the developing sleeve 114 between the poles. For this reason, the developer is peeled from the developing sleeve 114 at a position where the developing roller 110 and the agitating / conveying unit 120 face each other as the developing sleeve 114 rotates.

  Further, a layer regulating member 150 is provided on the upstream side in the rotation direction of the developing sleeve 114 with respect to the position where the developing sleeve 114 of the developing roller 110 and the photosensitive drum 30 face each other. The layer regulating member 150 is a member for leveling the developer attached on the peripheral surface of the developing sleeve 114 into a layer having a uniform thickness, and may be formed of, for example, a metal blade.

  The agitating / conveying units 120 and 130 agitate the magnetic carrier and the non-magnetic or weak magnetic toner constituting the developer to charge the carrier and the toner. The agitation conveyance units 120 and 130 include a first agitation conveyance unit 120 and a second agitation conveyance unit 130, as shown in FIGS.

  The first stirring / conveying unit 120 is disposed so as to face the developing roller 110 in a substantially vertical direction, and supplies the mixed and stirred developer to the developing roller 110. The first stirring / conveying unit 120 includes a first support shaft 122 and a first stirring blade 124. The first support shaft 122 is rotatably provided on the inner wall of the housing 5 via a bearing. The first stirring blade 124 is provided on the outer peripheral surface of the first support shaft 122, and includes a spiral inclined surface arranged in the longitudinal direction of the first support shaft 122.

  The second agitating and conveying unit 130 has a role of mixing and agitating the developer to sufficiently charge the developer, and conveys the charged developer to the first agitating and conveying unit 120. Similar to the first agitation transport unit 120, the second agitation transport unit 130 includes a second support shaft 132 and a second agitation blade 134. The second support shaft 132 is rotatably provided on the inner wall of the housing 5 via a bearing. The second stirring blade 134 is provided on the outer peripheral surface of the second support shaft 132, and includes a spiral inclined surface disposed in the longitudinal direction of the second support shaft 132. The first agitating and conveying unit 120 and the second agitating and conveying unit 130 are arranged in, for example, a substantially horizontal direction (the developing roller 110 and the first roller 110) so that the first support shaft 122 and the second support shaft 132 are substantially parallel. Are arranged side by side in a direction substantially perpendicular to the direction in which the first stirring and conveying unit 120 is adjacent.

  The developer conveyed while being agitated by the second agitating and conveying unit 130 moves to the peripheral surface of the developing roller 110 while being agitated and conveyed by the first agitating and conveying unit 120. The second agitating and conveying unit 130 is provided with a toner concentration sensor (not shown) for detecting the toner concentration, and when the toner concentration in the conveying path decreases, the toner tank 36 passes through the storage unit 140. Then, the developer is supplied into the conveyance path.

  The storage unit 140 is a space for temporarily storing the developer when the developing unit 100 is transported. The storage unit 140 is formed so as to be able to communicate with the second stirring / conveying unit 130 through communication units (reference numerals 147 and 148 in FIG. 3). The communication parts 147 and 148 are sealed with a seal member (not shown) when the developing unit 100 is transported, so that the developer stored in the storage part 140 does not flow into the stirring and conveying part 130. Then, when the developing unit 100 is attached to the image forming apparatus 1, the seal member is removed, the storage unit 140 and the agitation transport unit 130 are communicated, and the developer in the storage unit 140 flows into the agitation transport unit 130.

  The storage unit 140 according to the present embodiment is provided with an agitating and conveying member 141 for mixing and agitating and conveying the developer, similarly to the agitating and conveying units 120 and 130. The stirring and conveying member 141 includes a support shaft 142 and a stirring blade 144 that is provided on the outer peripheral surface of the support shaft 142 and has a spiral inclined surface arranged in the longitudinal direction of the support shaft 142. The stirring and conveying member 141 provided in the storage unit 140 operates together with the stirring and conveying units 120 and 130 when the image forming apparatus 1 is operated and the mixing and stirring of the developer is performed. The developer flowing through is mixed and stirred and conveyed. That is, when the developing unit 100 is transported, the storage unit 140 according to the present embodiment stores the developer in the storage unit 140 in order to prevent the developer from flowing out of the apparatus, and the developing unit 100 includes the image forming apparatus. After being attached to 1, it functions as a part of the agitation transport unit.

  For example, as shown in FIG. 2, the storage unit 140 is arranged side by side with the second agitation transport unit 130 in the vertical direction. Further, a developer replenishing port 149 to which a developer composed of toner and carrier is supplied from the toner tank 36 is formed in the storage unit 140. The toner supplied from the toner tank 36 is conveyed to the second agitation conveyance unit 130 by the agitation conveyance member in the storage unit 140 using the storage space 146 of the storage unit 140 as a conveyance path. In this embodiment, the developer supply port 149 is provided on the upper side (z-axis positive direction side) of the storage unit 140 on the x-axis negative direction side, but the present invention is not limited to such an example.

<Operation of development unit>
As described above, the developing unit 100 according to the present embodiment uses a storage unit 140 provided to store the developer when the developing unit 100 is transported as a part of the stirring and conveying unit when the image forming apparatus 1 is operated. To act as. Hereinafter, the operation of the developing unit 100 according to the present embodiment will be described with reference to FIGS. 2 and 3.

  First, when the developing unit 100 is transported, the developer in the developing unit 100 is stored in the storage unit 140. At this time, the communication parts 147 and 148 that connect the storage part 140 and the second transport agitation part 130 are sealed by the seal member. Thus, by storing the developer in the storage unit 140 and transporting the developing unit 100, it is possible to prevent the developer from leaking or spilling from the developing unit 100.

  Next, when the developing unit 100 is attached to the image forming apparatus 1, the seal members provided in the communication units 147 and 148 are removed, and the developer stored in the storage unit 140 flows into the stirring and mixing units 120 and 130. Then, when the image forming apparatus 1 is activated and the image signal of the image to be recorded is transmitted to the control unit, the control unit operates each unit based on the received image signal. At this time, the developing unit 100 also starts operation to develop the electrostatic latent image formed on the photosensitive drum 30. That is, as the developing sleeve 114 of the developing roller 110 rotates, the first support shaft 122 of the first agitating and conveying unit 120, the second support shaft 132 of the second agitating and conveying unit 130, and the agitating of the storage unit 140 are performed. Each of the support shafts 142 of the transport member 141 starts to rotate in a predetermined direction. These may be rotated by, for example, transmitting the rotational force of the same motor through a gear, or may be rotated by providing a separate motor.

  When the first support shaft 122, the second support shaft 132, and the support shaft 142 begin to rotate, the developer is conveyed in a predetermined direction by the stirring blades provided on the respective shafts. For example, as shown in FIG. 3, the developer flows in the x-axis positive direction in the first agitation transport unit 120, and the developer flows in the x-axis negative direction in the second agitation transport unit 130. Further, in the developing unit 100 according to the present embodiment, the storage space 146 of the storage unit 140 is also used as a developer conveyance path. For this reason, the storage unit 140 according to the present embodiment is provided with an agitating and conveying member 141 that mixes and agitates the developer and conveys it.

  At this time, the agitating / conveying member 141 is provided such that the developer conveying direction in the storage unit 140 is the same direction as the developer flow in the first agitating / conveying unit 120 (that is, the x-axis positive direction). . As described above, it is desirable that the developer flowing into the developing roller 110 is sufficiently mixed and agitated and charged in order to prevent image quality degradation and the like. For this reason, the distance for mixing and stirring the developer before the developer flows into the first stirring and conveying unit 120 is lengthened, and the time for mixing and stirring the developer is lengthened. In the developing unit 100 according to the present embodiment, the developer is sufficiently mixed and stirred after the developer flows through the second stirring and conveying unit 130 and the storage unit 140, and then the first stirring and conveying is performed. It flows into the part 120. Therefore, it is possible to prevent image quality degradation caused by charging failure of the developer.

  When both the developer flowing through the second agitating and conveying unit 130 and the storage unit 140 flow into the first agitating and conveying unit 120, a large amount of developer flows into the first agitating and conveying unit 120. Then, the developer cannot be effectively peeled off by the developing roller 110. For this reason as well, it is desirable that the developer transport direction in the first agitation transport unit 120 and the developer transport direction in the storage unit 140 be the same.

  Here, the 2nd stirring conveyance part 130 and the storage part 140 are arrange | positioned up and down in the z-axis direction, as shown in FIG. At this time, in order to realize the flow of the developer from the second agitation transport unit 130 to the storage unit 140 as shown in FIG. 3, the developer stays on the downstream side of the second agitation transport unit 130 in the developer transport direction. A retention portion 136 is formed so as to facilitate this. By providing the staying part 136 in the second stirring / conveying part 130, the developer flowing through the second stirring / conveying part 130 stays on the downstream side in the developer conveying direction of the second stirring / conveying part 130, and the second stirring The developer easily flows into the storage unit 140 located in the positive z-axis direction of the transport unit 130. The staying part 136 is provided at a position facing the communication part 147 with the storage part 140 on the downstream side in the developer conveying direction of the second stirring and conveying part 130. In this way, the flow of the developer from the second stirring / conveying unit 130 to the storage unit 140 can be realized.

<Configuration of staying part>
Here, based on FIG. 4 to FIG. 9, a configuration example of the staying part 136 formed in the second stirring and conveying part 130 will be described. FIG. 4 is a partial side view showing a configuration other than the staying part 136 of the second stirring and conveying part 130 according to the present embodiment. 5 to 9 are partial side views showing one configuration example of the staying portion 136 according to the present embodiment.

  First, based on FIG. 4, the structure of the 2nd support shaft 132 and the 2nd stirring blade 134 which are located other than the retention part 136 of the 2nd stirring conveyance part 130 is demonstrated. In portions other than the staying portion 136, the second agitating and conveying portion 130 has a second pitching blade 134 having an outer diameter D on the surface of a second support shaft 132 having an axial diameter d having a predetermined pitch W. Is provided. The pitch W refers to the interval between the second stirring blades 134 adjacent in the axial direction of the second support shaft 132. In the portion other than the staying portion 136 of the second agitating and conveying portion 130, the shaft diameter d, the outer shape D, and the pitch W have the same size.

  On the other hand, the staying part 136 provided in the second stirring / conveying part 130 is different from the other parts in the shape of the second support shaft 132 and the second stirring blade 134 so that the developer can easily stay. For example, as a first configuration example of the staying portion 136, as shown in FIG. 5, the shaft diameter d1 of the second support shaft 132 in the staying portion 136 is made larger than the shaft diameter d of other portions. Since the space where the developer flows is narrowed in the portion where the second support shaft 132 has the shaft diameter d1, the developer in the second agitating and conveying unit 130 is difficult to flow, and the developer is likely to stay. In this way, the developer flowing through the second stirring and conveying unit 130 can be retained and easily flowed to the storage unit 140.

  Further, for example, as a second configuration example of the staying part 136, a part of the second stirring blade 134 in the staying part 136 is cut off as shown in FIG. By removing the second stirring blade 134, the developer transport capability at the removal portion 137 decreases, and the developer in the second stirring transport unit 130 tends to stay. In this way, the developer flowing through the second stirring and conveying unit 130 can be retained and easily flowed to the storage unit 140.

  Further, for example, as a third configuration example of the staying part 136, as shown in FIG. 7, the outer diameter D1 of the second stirring blade 134 in the staying part 136 is made smaller than the outer diameter D of the other part. In the portion having the outer diameter D1 of the second agitating blade 134, the developer conveying ability is lowered, and the developer in the second agitating / conveying section 130 is likely to stay. In this way, the developer flowing through the second stirring and conveying unit 130 can be retained and easily flowed to the storage unit 140.

  Further, for example, as a fourth configuration example of the staying part 136, as shown in FIG. 8, a paddle 138 is provided on a part of the second stirring blade 134 in the staying part 136. The paddle 138 is a plate-like member and is provided so as to connect between the second stirring blades 134 adjacent in the axial direction of the second support shaft 132. Since the paddle 138 hinders the flow of the developer in the second agitating and conveying unit 130, the developer tends to stay in the portion where the paddle 138 is provided. In this way, the developer flowing through the second stirring and conveying unit 130 can be retained and easily flowed to the storage unit 140.

  Further, for example, as a fifth configuration example of the staying part 136, as shown in FIG. 9, the pitch W1 of the second stirring blades 134 in the staying part 136 is made smaller than the pitch W of other parts. The amount of the developer conveyed at the pitch W1 portion of the second stirring blade 134 is reduced as compared with the pitch W portion. For this reason, the developer in the second agitating and conveying unit 130 is likely to stay. In this way, the developer flowing through the second stirring and conveying unit 130 can be retained and easily flowed to the storage unit 140.

  The configuration example of the staying unit 136 provided on the downstream side in the developer transport direction of the second stirring transport unit 130 has been described above with reference to FIGS. 4 to 9. By providing such a staying portion 136, the flow of the developer on the downstream side in the developer transport direction of the second agitating and transporting portion 130 becomes slow, and the developer stays. As a result, the developer can easily flow from the second agitating and conveying unit 130 toward the storage unit 140.

<Longer life of developer in development unit>
The developing unit 100 according to the present embodiment supplies a carrier together with the toner when supplying the toner reduced by the developing process of the electrostatic latent image into the current unit 100. As the developer is supplied in this way, the number of carriers that are not used in the development process increases. Therefore, in the conventional developing device, a discharging mechanism that discharges the increased developer into the developing device or a discharged developer is provided. A collection tank for storage was provided. On the other hand, the developing unit 100 according to the present embodiment is not provided with a developer discharging mechanism or a collection tank.

  The developing unit 100 first performs development processing of the electrostatic latent image using the developer initially stored in the storage unit 140. When the toner concentration sensor detects that the toner concentration in the developing unit 100 has decreased as the developing process is performed, the developer is supplied into the developing unit 100 from the developer replenishing unit 149 of the storage unit 140. The developer supplied from the developer replenishing unit 149 is agitated and conveyed by the agitating and conveying member 141 of the storage unit 140 and flows into the second agitating and conveying unit 130, and the developer is second agitated and conveyed according to the conveying direction. The unit 130, the first stirring and conveying unit 120, and the storage unit 140 are circulated. In this way, by supplying a new developer to the developing unit 100, the toner density in the developing unit 100 can be set to a predetermined value (first toner density) or more.

  As described above, when the developing unit 100 detects a decrease in the toner density in the developing unit 100 by the toner density sensor, the developer is supplied from the toner tank 36 to the developing unit 100 by the developer supply controller (not shown). Instruct them to supply. The developing unit 100 includes a storage unit (not shown) that stores the developer amount supplied into the developing unit 100 and a cumulative storage unit (not shown) that stores the cumulative supply amount of the developer. it can. The developer supply control unit supplies the developer to the developer transport path of the developing unit 100 based on the developer amount stored in the storage unit.

  After repeating such processing, a predetermined amount or more of developer is stored in the developing unit 100, and the value of a cumulative storage unit (not shown) that stores the cumulative supply amount of developer is greater than the predetermined value. When it becomes larger, the user is requested to replace the developing unit 100. By replacing the developing unit 100, a new developer can be used.

  Since the developing unit 100 according to the present embodiment has a structure that does not discharge the developer, it is not necessary to include a developer discharging mechanism or a collection tank. Therefore, it is not necessary to provide a separate discharge mechanism that was conventionally required when mechanically discharging the deteriorated developer, and cleaning associated with chipping of the edge of the cleaning blade that occurred when the developer was electrically discharged. It is possible to prevent the occurrence of defects and scratches on the photosensitive drum. Thereby, the lifetime improvement of a developing agent is realizable.

  Furthermore, since a recovery tank for storing the discharged developer is not required, the development unit 100 can be reduced in size and the cost can be reduced. Further, by using the storage space of the storage unit 140 that temporarily stores the developer during transportation of the developing unit 100 as a stirring and conveying path, the space in which the developer can be stored in the developing unit 100 is increased. As a result, the total supply amount of developer that can be supplied to the developing unit 100 can be increased, and the replacement frequency of the developing unit 100 can be reduced.

  The configuration and operation of the developing unit 100 according to the embodiment of the present invention have been described above. According to the present embodiment, the agitating and conveying member 141 that conveys the developer while mixing and agitating the developer is provided in the storage unit 140 that temporarily stores the developer when the developing unit 100 is transported. Accordingly, after the developer in the storage unit 140 is caused to flow into the agitation conveyance path, the storage space 146 of the storage unit 140 can also be used as the agitation conveyance path for the developer. Therefore, the time for mixing and stirring the developer before the developer is supplied to the developing roller 110 can be extended, and the developer can be sufficiently charged. At this time, the staying part 136 is provided on the downstream side of the second agitation transport part 130 in the developer transport direction and facing the communication part 147 with the storage part 140. As a result, the developer stays in the staying portion 136, and the developer can easily flow into the storage portion 140, so that the developer in the developing unit 100 is smoothly circulated.

  Furthermore, the developing unit 100 according to the present embodiment does not include a mechanism for discharging the deteriorated developer from the developing unit 100 and a recovery tank. This makes it possible to reduce the developer deterioration rate by the developer replenished with respect to the developer deterioration accompanying the image forming operation, and as a result, the life of the developer can be extended. Further, since a space for providing these mechanisms and a collection tank is unnecessary, the image forming apparatus can be downsized.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

  For example, in the above-described embodiment, the storage unit 140 is provided in a substantially vertical direction (gravity direction) to the second stirring and conveying unit 130, but the present invention is not limited to such an example. For example, the storage unit 140 may be provided at an upper position in the gravity direction with respect to the first agitation transport unit 120 and the second agitation transport unit 130.

1 is an explanatory diagram showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention. It is explanatory drawing which shows the structure of the developing unit concerning the embodiment. FIG. 6 is an explanatory diagram for describing a flow of a developer in the developing unit according to the embodiment. It is a partial side view which shows structures other than the retention part of the 2nd stirring conveyance part concerning the embodiment. It is a partial side view which shows the example of 1 structure of the retention part concerning the embodiment. It is a partial side view which shows the other structural example of the retention part concerning the embodiment. It is a partial side view which shows the other structural example of the retention part concerning the embodiment. It is a partial side view which shows the other structural example of the retention part concerning the embodiment. It is a partial side view which shows the other structural example of the retention part concerning the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 100 Developing unit 110 Developing roller 112 Magnet 114 Developing sleeve 120 1st stirring conveyance part 122 1st support shaft 124 1st stirring blade 130 2nd stirring conveyance part 132 2nd support shaft 134 2nd Stirring blade 136 Retaining portion 137 Removal portion 138 Paddle 140 Storage portion 141 Stirring conveyance member 142 Support shaft 144 Stirring blade 147, 148 Communication portion 149 Developer supply port

Claims (9)

An agitating and conveying unit having a mixing and agitating member that contains a developer composed of a carrier and toner, mixes and agitates the developer, and conveys the developer in a predetermined conveying direction;
A developer that is provided opposite to an electrostatic latent image carrier that carries an electrostatic latent image and that supports the developer stirred and conveyed by the agitating and conveying unit on a peripheral surface and supplies the developer to the electrostatic latent image carrier. A carrier,
A storage unit that internally stores a developer, has a stirring and conveying member that mixes and agitates the developer and conveys the developer in a predetermined conveying direction, and
A developer replenishing section that replenishes the developer according to the amount of toner used;
With
On the upstream side and the downstream side in the developer conveyance direction in the agitation conveyance unit, a communication unit that communicates the storage unit and the agitation conveyance unit is provided, respectively.
The communication part is provided with a removable sealing member that temporarily blocks the communication part,
The developing device in which the stirrer / conveyor is provided with a staying part for retaining the developer at a position corresponding to the communication part provided on the downstream side of the stirrer / conveyor in the developer transport direction. The stirring and conveying unit includes at least two stirring and conveying members,
2. The developer conveyance direction according to claim 1, wherein the agitation conveyance member provided in the agitation conveyance unit facing the developer carrying member and the agitation conveyance member provided in the storage unit are the same. Development device. The stirring and conveying member provided in the stirring and conveying unit and the storage unit,
A support shaft extending in the developer transport direction and rotatably provided;
A stirring blade provided on the outer peripheral surface of the support shaft and transporting the developer while mixing and stirring;
Consists of
The developing device according to claim 1, wherein the staying portion is provided on the downstream side in the developer conveyance direction of the agitation conveyance member provided in the agitation conveyance unit facing the storage unit.   The developing device according to claim 3, wherein the stirring and conveying member provided with the staying portion is formed such that the shaft diameter of the support shaft located at the staying portion is larger than the shaft diameter of the support shaft at another position.   The developing device according to claim 3, wherein the stirring and conveying member provided with the staying portion has the stirring blade located in the staying portion removed.   The developing device according to claim 3, wherein the stirring and conveying member provided with the staying portion is formed such that an outer diameter of the stirring blade located at the staying portion is smaller than an outer diameter of the stirring blade at another position.   The developing device according to claim 3, wherein the stirring and conveying member provided with the staying portion is provided with a paddle that connects between the stirring blades adjacent to each other on the stirring blade located in the staying portion.   In the stirring / conveying member provided with the staying portion, the pitch representing the interval between the stirring blades adjacent to each other in the support shaft direction of the stirring blade located in the staying portion is larger than the pitch of the stirring blades in other positions. The developing device according to claim 3, wherein the developing device is formed small. An electrostatic latent image carrier that carries an electrostatic latent image on a peripheral surface;
A developing device for developing the electrostatic latent image on the electrostatic latent image carrier;
With
The developing device includes:
An agitating and conveying unit having a mixing and agitating member that contains a developer composed of a carrier and toner, mixes and agitates the developer, and conveys the developer in a predetermined conveying direction;
A developer carrying member provided facing the electrostatic latent image carrying member and carrying the developer stirred and conveyed by the stirring and conveying unit on a peripheral surface and supplying the developer to the electrostatic latent image carrying member;
A storage unit that internally stores a developer, has a stirring and conveying member that mixes and agitates the developer and conveys the developer in a predetermined conveying direction, and
A developer replenishing section that replenishes the developer according to the amount of toner used;
With
On the upstream side and the downstream side in the developer conveyance direction in the agitation conveyance unit, a communication unit that communicates the storage unit and the agitation conveyance unit is provided, respectively.
The communication part is provided with a removable sealing member that temporarily blocks the communication part,
The image forming apparatus, wherein the stirrer / conveyor is provided with a staying part for retaining the developer at a position corresponding to the communication part provided on the downstream side of the stirrer / conveyor in the developer transport direction.

Images