JP6128426B2 - Developer supply device and image forming apparatus - Google Patents

Description

  The present invention relates to a developer supply device and an image forming apparatus for supplying a developer to a developing device.

  In image forming apparatuses such as printers, copiers, and facsimile machines, a developer replenishing device is generally provided that stores a developer such as toner and replenishes the developer from a developer storage container that is detachable from the apparatus body. I have.

  When the developer storage container is emptied, the developer is not supplied from the developer storage container, so that an abnormal image such as a decrease in image density occurs. For this reason, the image forming operation must be stopped until the empty developer container is replaced, resulting in downtime of the apparatus.

  Patent Document 1 describes an image forming apparatus that can perform an image forming operation until an empty developer container is replaced. The image forming apparatus described in Patent Literature 1 transports the developer stored in the developer storage container to the developing device, and a developer storage unit that temporarily stores the developer supplied from the developer storage container. And a developer replenishing device including a transport unit. A screw that stirs and conveys the developer in the developer reservoir is provided in the developer reservoir. When replenishing the developer to the developing device, the screw is driven to deliver the developer in the developer reservoir to the transport unit. The developer delivered to the transport unit is transported to the developing device by a transport coil provided in the transport unit, and a predetermined developer is supplied to the developing device.

  Further, the developer replenishing device described in Patent Document 1 is provided with developer detecting means for detecting the developer in the developer storage section. The developer detection means is provided at a predetermined height from the bottom surface of the developer storage section. When the volume of the developer in the developer reservoir becomes less than a predetermined value, the developer is not detected by the developer detector, and the supply of the developer from the developer storage container to the developer reservoir is started. Then, when the volume of the developer in the developer reservoir becomes equal to or greater than a predetermined value, the developer detection unit detects the developer and stops supplying the developer to the developer reservoir.

  In the image forming apparatus described in Patent Document 1, the amount of developer consumed by image formation is temporarily stored in the developer storage unit of the developer supply device until the empty developer storage container is replaced. Can be covered by developer. Thus, a desired image can be obtained even if image formation is performed until the empty developer container is replaced.

  In order for an appropriate amount of developer to be stored in the developer storage section, the positional relationship between the supply port for supplying the developer in the developer storage container to the developer storage section and the developer detection means is important. Become. For example, when the supply port is located in the vicinity of the developer detection means, the developer is not sufficiently stored in the developer storage portion because the developer supplied in the vicinity of the supply port accumulates in a mountain shape. Then, the developer detecting means detects the developer. Accordingly, the supply of the developer is stopped when the developer is not sufficiently stored in the developer storage section. As a result, the developer in the developer storage section is exhausted as soon as the developer in the developer storage container becomes empty. Therefore, before the empty developer storage container is replaced, the developer in the developer storage section is lost, and there is a problem that the image forming operation must be stopped. On the other hand, because the developer supplied in the vicinity of the supply port accumulates in a mountain shape, even if the developer is supplied to a location far from the supply port, the bulk of the developer hardly increases. Therefore, when the developer detection means is located at a location far away from the supply port, there arises a problem that the developer overflows from the developer reservoir.

  For this reason, the positional relationship between the supply port and the developer detection means is very important. However, due to the layout of the apparatus, the positional relationship between the supply port and the developer detection unit may not be an appropriate relationship.

  Here, when the developer is replenished to the developer storage section, the developer in the developer storage section is agitated to diffuse the amount of the developer in the developer storage section so that the developer has a mountain shape near the supply port. It is conceivable to have a configuration that prevents the material from being deposited on the surface. However, in this case, if the drive for supplying the developer and the drive for stirring the developer are different drive sources, the stirring and conveying member is used in addition to driving the supply drive source during the developer supplying operation. To drive the replenishment drive source.

  The present invention has been made in view of the above problems, and an object thereof is to provide a developer supply device and an image forming apparatus that can suppress the number of drive sources that are driven during a developer supply operation.

In order to achieve the above object, the invention of claim 1 includes a developer storage container storing a developer, a developer storage section for temporarily storing the developer supplied from the developer storage container, Provided in the developer reservoir, and a developer that is provided in the developer reservoir, agitates the developer in the developer reservoir, and develops the developer. From the bottom of the developer storage section; a stirring transport member that transports the developer to the transport section; a replenishment drive source that drives the transport member and the stirring transport member when replenishing the developer to the developing device; A developer detection unit disposed at a distance; a supply member that supplies the developer in the developer storage container from the supply port to the developer storage unit; and a supply source for driving that drives the supply member In the detection result of the developer detection means Zui, in the developer supply device and a control means for controlling the supply drive source, the stirring carrying member, wherein configured to be driven by the supply drive source, the stirring conveying member and the conveying The member is rotated by itself to convey the developer, and the developer storage unit and the conveyance unit are separated by a partition wall extending in a rotation axis direction of the conveyance member between the stirring conveyance member and the conveyance member. And an opening through which the developer is transferred from the developer reservoir to the transport unit is provided at both ends of the partition wall in the rotation axis direction of the transport member .

  According to the present invention, the stirring and conveying member is driven by the supply source for supply. Therefore, during the supply operation, the stirring and conveying member can be driven only by driving the supply source for supply. . As a result, the number of drive sources that are driven during the developer supply operation can be reduced.

1 is a schematic configuration diagram of a copier according to an embodiment. FIG. 2 is a schematic configuration diagram of a developing device and a photoreceptor. FIG. 3 is a perspective view showing a developing device for each color and a configuration of the entire developer replenishing device that replenishes the developing device with premix toner. FIG. 3 is a perspective view of a developer storage container for K color. FIG. 3 is a perspective view of a color developer storage container. Sectional drawing of the developer storage container for color. FIG. 3 is a cross-sectional perspective view of a developer storage container for K color. The enlarged view which shows the coupling attachment part periphery of the developer storage container for K. FIG. The perspective view which shows a developing agent supply drive part. The front view of a developing agent supply drive part. The perspective view which shows the structure of a sub hopper. The perspective view which shows the internal structure of a sub hopper. The figure which shows the developer storage part and conveyance part in a sub hopper. FIG. 3 is a block diagram illustrating an example of a main configuration of a control system in the developer supply device. FIG. 6 is a diagram for explaining movement of premix toner when supplying developer from a developer storage container to a developer storage section. FIG. 6 is a diagram illustrating movement of premix toner when premix toner is supplied to the developing device. FIG. 4 is a diagram for explaining movement of a premix toner when a replenishment operation to a developing device and a supply operation to a developer storage unit are simultaneously performed. The figure explaining the conventional malfunction. The figure explaining the effect of this embodiment. The figure which shows the modification of a sub hopper.

Hereinafter, as an image forming apparatus to which the present invention is applied, an embodiment of a tandem type color laser copying machine (hereinafter simply referred to as “copying machine”) in which a plurality of photoconductors are arranged in parallel will be described.
FIG. 1 is a schematic configuration diagram of a copying machine according to an embodiment. The copier includes a printer unit 100, a paper feeding device 200 on which the printer unit 100 is placed, a scanner 300 fixed on the printer unit 100, and the like. An automatic document feeder 400 fixed on the scanner 300 is also provided.

  The printer unit 100 includes an image forming unit including four sets of process cartridges 18Y, 18M, 18C, and 18K for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K). 20 is provided. Y, M, C, and K attached to the numbers of the respective symbols indicate members for yellow, cyan, magenta, and black (the same applies hereinafter). In addition to the process cartridges 18Y, 18M, 18C, and 18K, an optical writing unit 21, an intermediate transfer unit 17, a secondary transfer device 22, a resist roller pair 49, a belt fixing type fixing device 25, and the like are disposed. .

  The optical writing unit 21 includes a light source (not shown), a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates the surface of a photoconductor described later with laser light based on image data.

  The process cartridges 18Y, 18M, 18C, and 18K include a drum-shaped photosensitive member 1, a charger, a developing device 4, a drum cleaning device, a static eliminator, and the like.

Hereinafter, the yellow process cartridge 18 will be described.
The surface of the photoreceptor 1Y is uniformly charged by a charger as charging means. The surface of the photoreceptor 1 </ b> Y that has been subjected to charging processing is irradiated with laser light that has been modulated and deflected by the optical writing unit 21. Then, the potential of the irradiation part (exposure part) is attenuated. By this attenuation, an electrostatic latent image for Y is formed on the surface of the photoreceptor 1Y. The formed electrostatic latent image for Y is developed by the developing device 4Y as developing means to become a Y toner image.
The Y toner image formed on the Y photoconductor 1Y is primarily transferred to an intermediate transfer belt 101 described later. The surface of the photoreceptor 1Y after the primary transfer is cleaned of the transfer residual toner by a drum cleaning device.
In the Y process cartridge 18Y, the photoconductor 1Y cleaned by the drum cleaning device is discharged by the charge eliminator. Then, it is uniformly charged by the charger and returns to the initial state. The series of processes as described above is the same for the other process cartridges 18M, 18C, and 18K.

Next, the intermediate transfer unit will be described.
The intermediate transfer unit 17 includes an intermediate transfer belt 101, a belt cleaning device 102, and the like. Further, it also includes a tension roller 14, a driving roller 15, a secondary transfer backup roller 16, four primary transfer bias rollers 62Y, M, C, and K.
The intermediate transfer belt 101 is tensioned by a plurality of rollers including a tension roller 14. Then, it is endlessly moved clockwise in the drawing by the rotation of the driving roller 15 driven by a belt driving motor (not shown).
The four primary transfer bias rollers 62Y, 62M, 62C, and 62K are arranged so as to be in contact with the inner peripheral surface side of the intermediate transfer belt 101, respectively, and receive primary transfer bias from a power source (not shown). Further, the intermediate transfer belt 101 is pressed toward the photoreceptors 1Y, 1M, 1C, and 1K from the inner peripheral surface side to form primary transfer nips. In each primary transfer nip, a primary transfer electric field is formed between the photosensitive member and the primary transfer bias roller due to the influence of the primary transfer bias.
The above-described Y toner image formed on the Y photoconductor 1Y is primarily transferred onto the intermediate transfer belt 101 due to the influence of the primary transfer electric field and nip pressure. On the Y toner image, the M, C, K toner images formed on the M, C, K photoconductors 1M, C, K are sequentially superposed and primarily transferred. By this primary transfer of superposition, a four-color superposed toner image (hereinafter referred to as a four-color toner image) that is a multiple toner image is formed on the intermediate transfer belt 101.
The four-color toner image superimposed and transferred on the intermediate transfer belt 101 is secondarily transferred onto a transfer sheet (not shown) as a recording medium at a secondary transfer nip described later. Transfer residual toner remaining on the surface of the intermediate transfer belt 101 after passing through the secondary transfer nip is cleaned by a belt cleaning device 102 that sandwiches the belt with the driving roller 15 on the left side in the drawing.

Next, the secondary transfer device 22 will be described.
Below the intermediate transfer unit 17 in the figure, a secondary transfer device 22 is disposed in which a paper conveying belt 24 is stretched by two stretching rollers 23. The paper transport belt 24 is moved endlessly in the counterclockwise direction in the drawing in accordance with the rotational drive of at least one of the stretching rollers 23. One of the two stretching rollers 23 disposed on the right side in the drawing sandwiches the intermediate transfer belt 101 and the paper transport belt 24 between the secondary transfer backup roller 16 of the intermediate transfer unit 17. It is out. By this sandwiching, a secondary transfer nip is formed in which the intermediate transfer belt 101 of the intermediate transfer unit 17 and the paper transport belt 24 of the secondary transfer device 22 come into contact with each other. A secondary transfer bias having a polarity opposite to that of the toner is applied to the one stretching roller 23 by a power source (not shown). By applying the secondary transfer bias, the four-color toner image on the intermediate transfer belt 101 of the intermediate transfer unit 17 is electrostatically moved from the belt side toward the one stretching roller 23 side in the secondary transfer nip. A next transfer electric field is formed. The transfer paper fed into the secondary transfer nip so as to synchronize with the four-color toner image on the intermediate transfer belt 101 by a registration roller pair 49 described later has four colors affected by the secondary transfer electric field and nip pressure. The toner image is secondarily transferred. Instead of the secondary transfer method in which the secondary transfer bias is applied to one of the stretching rollers 23 as described above, a charger for charging the transfer paper in a non-contact manner may be provided.

  In the paper feeding device 200 provided at the lower part of the copying machine main body, a plurality of paper feeding cassettes 44 in which a plurality of transfer sheets can be stacked and accommodated in a bundle of sheets are arranged so as to overlap in the vertical direction. Has been. Each paper feed cassette 44 presses the paper feed roller 42 against the uppermost transfer paper in the paper bundle. Then, by rotating the paper feed roller 42, the uppermost transfer paper is sent out toward the paper feed path 46.

  The paper feed path 46 that receives the transfer paper fed from the paper feed cassette 44 has a plurality of conveying roller pairs 47 and a registration roller pair 49 provided near the end in the path. Then, the transfer paper is conveyed toward the registration roller pair 49. The transfer sheet conveyed toward the registration roller pair 49 is sandwiched between the rollers of the registration roller pair 49. On the other hand, in the intermediate transfer unit 17, the four-color toner image formed on the intermediate transfer belt 101 enters the secondary transfer nip as the belt moves endlessly. The registration roller pair 49 sends out the transfer paper sandwiched between the rollers at a timing at which the transfer paper can be brought into close contact with the four-color toner image at the secondary transfer nip. Thereby, in the secondary transfer nip, the four-color toner image on the intermediate transfer belt 101 is in close contact with the transfer paper. Then, it is secondarily transferred onto the transfer paper and becomes a full color image on the white transfer paper. The transfer paper on which the full-color image is formed in this manner exits the secondary transfer nip as the paper transport belt 24 moves endlessly, and then is sent from the paper transport belt 24 to the fixing device 25.

  The fixing device 25 includes a belt unit that moves the fixing belt 26 endlessly while being stretched by two rollers, and a pressure roller 27 that is pressed toward one roller of the belt unit. The fixing belt 26 and the pressure roller 27 are in contact with each other to form a fixing nip, and the transfer paper received from the paper transport belt 24 is sandwiched therebetween. Of the two rollers in the belt unit, the roller that is pressed from the pressure roller 27 has a heat source (not shown) inside, and pressurizes the fixing belt 26 by the generated heat. The pressed fixing belt 26 heats the transfer paper sandwiched in the fixing nip. The full color image is fixed on the transfer paper by the influence of the heating and the nip pressure.

  The transfer paper subjected to the fixing process in the fixing device 25 is stacked on the stack portion 57 provided outside the left side plate in the drawing of the printer housing, or forms a toner image on the other surface. To the secondary transfer nip described above.

  When a document (not shown) is copied, for example, a bundle of sheet documents is set on the document table 30 of the automatic document feeder 400. However, when the original is a single-sided original that is closed in a main form, it is set on the contact glass 32. Prior to this setting, the automatic document feeder 400 is opened with respect to the copying machine main body, and the contact glass 32 of the scanner 300 is exposed. Thereafter, the single-bound original is pressed by the closed automatic document feeder 400.

  When a copy start switch (not shown) is pressed after the document is set in this way, the document reading operation by the scanner 300 starts. However, when a sheet document is set on the automatic document feeder 400, the automatic document feeder 400 automatically moves the sheet document to the contact glass 32 prior to the document reading operation. In the document reading operation, first, the first traveling body 33 and the second traveling body 34 start traveling together, and light is emitted from a light source provided in the first traveling body 33. Then, the reflected light from the document surface is reflected by a mirror provided in the second traveling body 34, passes through the imaging lens 35, and then enters the reading sensor 36. The reading sensor 36 constructs image information based on the incident light.

  In parallel with such a document reading operation, each device in each of the process cartridges 18Y, 18M, 18C, 18K, the intermediate transfer unit 17, the secondary transfer device 22, and the fixing device 25 starts driving. Based on the image information constructed by the reading sensor 36, the optical writing unit 21 is driven and controlled, and Y, M, C, and K toner images are formed on the respective photoreceptors 1Y, 1M, 1C, and 1K. Is done. These toner images become four-color toner images superimposed and transferred on the intermediate transfer belt 101.

  Further, almost simultaneously with the start of the document reading operation, the paper feeding operation is started in the paper feeding device 200. In this paper feeding operation, one of the paper feeding rollers 42 is selectively rotated, and the transfer paper is sent out from one of the paper feeding cassettes 44 accommodated in the paper bank 43 in multiple stages. The fed transfer sheets are separated one by one by the separation roller 45 and enter the reverse feeding path 46, and then conveyed toward the secondary transfer nip by the conveyance roller pair 47. In some cases, paper feeding from the manual feed tray 51 is performed instead of such paper feeding from the paper feeding cassette 44. In this case, after the manual feed roller 50 is selectively rotated to feed the transfer paper on the manual feed tray 51, the separation roller 52 separates the transfer paper one by one and feeds it to the manual feed path 53 of the printer unit 100. Make paper.

  In the case of forming another color image composed of toner of two or more colors, the copying machine stretches the intermediate transfer belt 101 so that the upper stretched surface is almost horizontal, Photoconductors 1Y, 1M, 1C, and 1K are brought into contact with each other. On the other hand, when forming a monochrome image composed of only K toner, the intermediate transfer belt 101 is tilted to the lower left in the drawing by a mechanism (not shown) and the upper stretched surface is set to Y, M, C. The photoconductors 1Y, 1M, and 1C are separated. Of the four photoconductors 1Y, 1M, 1C, and 1K, only the K photoconductor 1K is rotated counterclockwise in the drawing to form only the K toner image. At this time, for Y, M, and C, not only the photosensitive member 1 but also the developing device is stopped to prevent unnecessary consumption of the photosensitive member and the developer.

  The copying machine includes a control unit (not shown) configured by a CPU or the like that controls the following devices in the copying machine, and an operation display unit (not shown) configured by a liquid crystal display, various key buttons, and the like. The operator sends a command to the control unit by a key input operation on the operation display unit, so that one of the three modes is selected from the three-sided print mode, which is a mode for forming an image only on one side of the transfer paper. You can choose one. The three single-sided printing modes include a direct discharge mode, a reverse discharge mode, and a reverse decal discharge mode.

FIG. 2 is an enlarged configuration diagram illustrating the developing device 4 and the photosensitive member 1 included in one of the four process cartridges 18Y, 18M, 18C, and 18K. Since the four process cartridges 18Y, 18M, 18C, and 18K have substantially the same configuration except that the colors of the toners to be handled are different, they are referred to as “Y”, “M”, “C”, and “K” in FIG. Subscripts are omitted.
As shown in FIG. 2, the surface of the photosensitive member 1 is charged by a charging device (not shown) while rotating in the direction of arrow G in the drawing. The charged surface of the photoreceptor 1 is supplied with toner from the developing device 4 to a latent image on which an electrostatic latent image is formed by laser light emitted from an exposure device (not shown), thereby forming a toner image.

The developing device 4 has a developing roller 5 as a developer carrying member for supplying toner to the latent image on the surface of the photoreceptor 1 while moving the surface in the direction of arrow I in the drawing. Further, a supply screw 8 is provided as a supply conveyance member that conveys the developer in the depth direction of FIG. 2 while supplying the developer to the developing roller 5. The supply screw 8 is a developer conveying screw that includes a rotating shaft and a blade portion provided on the rotating shaft and conveys the developer in the axial direction by rotating.
A developing doctor 12 as a developer regulating member for regulating the developer supplied to the developing roller 5 to a thickness suitable for development is provided on the downstream side of the surface moving direction from the portion facing the supply screw 8 of the developing roller 5. ing.
The developed developer that has passed through the developing section is collected downstream from the developing section, which is the facing portion of the developing roller 5 with respect to the photoconductor 1, and the collected developer is collected in the same direction as the supply screw 8. A recovery screw 6 is provided as a recovery transport member for transporting to the front. A supply conveyance path 9 including a supply screw 8 is provided in the lateral direction of the developing roller 5, and a recovery conveyance path 7 serving as a recovery conveyance path including the recovery screw 6 is provided below the development roller 5.

The developing device 4 is provided with a stirring conveyance path 10 in parallel with the collection conveyance path 7 below the supply conveyance path 9. The agitating and conveying path 10 includes an agitating screw 11 serving as an agitating and conveying member that conveys the developer to the near side in the figure, which is in the opposite direction to the supply screw 8 while agitating the developer.
The supply conveyance path 9 and the stirring conveyance path 10 are partitioned by a first partition wall 133 as a partition member. In the first partition wall 133, the supply conveyance path 9 and the agitation conveyance path 10 are partitioned at both ends on the front side and the back side in the drawing, and the supply conveyance path 9 and the agitation conveyance path 10 communicate with each other. doing.
The supply conveyance path 9 and the recovery conveyance path 7 are both partitioned by the first partition wall 133, but an opening is provided at a location where the supply conveyance path 9 and the recovery conveyance path 7 of the first partition wall 133 are partitioned. Absent.
Further, the two conveyance paths of the stirring conveyance path 10 and the collection conveyance path 7 are partitioned by a second partition wall 134 as a partition member. The second partition wall 134 has an opening on the front side in the figure, and the agitation transport path 10 and the collection transport path 7 communicate with each other.

The developer thinned by the developing doctor 12 on the developing roller 5 is transported to a developing region which is a portion facing the photosensitive member 1 for development.
The developer after the development is collected in the collection conveyance path 7, conveyed to the front side of the cross section in FIG. 2, and to the agitation conveyance path 10 through the opening of the first partition wall 133 provided in the non-image area portion. Developer is transferred.

  Further, in the supply conveyance path 9, when the developer in the supply conveyance path 9 exceeds a predetermined volume, a developer discharge port 94 for discharging a part thereof to the outside of the developing device 4 and a developer discharge port 94. And a discharge conveyance path 2 provided with a discharge conveyance screw 2a for conveying the developer discharged from the developing device 4 to the outside. The discharge conveyance path 2 is disposed on the downstream side in the conveyance direction of the supply conveyance path 9 so as to be adjacent to the supply conveyance path 9 with the partition wall 135 interposed therebetween, and the developer discharge port 94 is connected to the supply conveyance path 9 and the discharge conveyance path 2. Is an opening provided in the partition wall 135 so as to communicate with each other.

A developer containing toner and carrier is supplied to the stirring and conveying path 10 from the replenishment port provided on the upper side of the stirring and conveying path 10 near the opening of the first partition wall 133 on the upstream side in the developer conveying direction in the stirring and conveying path 10. To be replenished. Hereinafter, the developer in which the toner supplied to the developing device 4 and the carrier are mixed is referred to as premix toner. In the present embodiment, the toner amount in the premix toner is 25 to 35% by weight, and the toner amount in the developer in the developing device 4 is 4 to 10% by weight.
In this embodiment, toner having an outflow temperature of 90 ° C. or lower is used. By using a toner having an outflow temperature of 90 ° C. or lower, fixing can be performed at a low temperature, and energy saving and speeding up of the image forming apparatus can be achieved.

FIG. 3 is a perspective view showing the overall configuration of each color developing device 4Y, 4C, 4M, 4K and developer replenishing device 70Y, 70C, 70M, 70K for replenishing the developing device with premixed toner.
The developer supply devices 70Y, 70C, 70M, and 70K are disposed above the developing devices 4Y, 4C, 4M, and 4K. The developer supply device 70 has a developer storage container 71 that stores premixed toner, and a sub hopper 90 (see FIG. 10) described later (in this figure, Y and M developer storage containers). 71Y, 71M are shown). The developer storage container 71 is held by the container holding unit 77. The container holding part 77 is divided into four parts, and the developer storage containers 71 of K color, C color, M color, and Y color are held in order from the left side in the drawing. The developer storage container 71 is detachably held with respect to the container holding part 77. When the premix toner is removed from the developer storage container 71, the user pulls out the developer storage container 71 from the container holding part 77, and A new developer container 71 is inserted into the container holder 77. As a result, new premix toner is supplied to a sub hopper 90 (see FIG. 11) described later.

  The developer supply devices 70Y, 70C, 70M, and 70K are arranged on the front side of the image forming apparatus, and can access the developer storage container 71 from the front side of the image forming apparatus.

4 is a perspective view of a developer storage container 71K for K color, and FIG. 5 is a storage of developer for color (Y, M, C) used in a Y, M, C developer supply device. It is a perspective view of container 71YMC.
In this embodiment, as shown in FIGS. 4 and 5, the K-color developer storage container 71K has a larger volume than the color (Y, M, C) developer storage container 71YMC. A typical user is more likely to output a black and white image than a full color image. For this reason, the toner consumption speed is faster for black than for color (Y, M, C). Therefore, when the K-color developer storage container 71K has the same shape as the color developer storage container, the K-color developer storage container 71 is frequently replaced, which is convenient for the user. Deteriorate. For this reason, in this embodiment, the volume of the developer storage container 71K for K color is made larger than the volume of the developer storage container 71YMC for color (Y, M, C), and the color (Y , M, C) more premix toner than the developer storage container 71YMC.

FIG. 6 is a cross-sectional view of the color developer storage container 71YMC.
As shown in FIG. 6, the color developer storage container 71YMC includes a container main body 71A, a transport screw 72 installed in the container main body 71A, and an agitator 73 as a stirring member. The agitator 73 is disposed in parallel with the transport screw 72 in the container main body 71A.

  The agitator 73 includes a shaft portion 731, a bone portion as a connection portion molded integrally with the shaft portion 731, and a wing portion 732 attached to the bone portion 734. The wing part 732 is supported by the shaft part 731 via the bone part 734. The agitator 73 is driven by a developer supply driving unit 80 (see FIGS. 9 and 10) described later, and rotates integrally with a shaft portion 731 disposed in parallel with the conveying screw 72. Then, the premix toner in the container main body 71A is transported so as to be moved toward the transport screw 72 while stirring. The shaft portion 731 and the bone portion 734 of the agitator 73 are rigid bodies having rigidity. Further, since the wing portion 732 of the agitator 73 is flexible, the agitator 73 rotates while the wing portion 732 is bent by the wing portion 732 coming into contact with the inner wall of the container main body 71A.

  The shaft portion 731 and the bone portion 734, which are rigid bodies having the rigidity of the agitator 73, are simply and preferably integrally formed of metal or the like, but other materials or manufacturing methods may be used. In addition, the flexible wing portion 732 is preferably manufactured from a material having low rigidity. For example, a flexible material such as a sheet made of PET (polyethylene terephthalate), PE (polyethylene), PP (polypropylene), PPS (polyphenylene sulfide), or the like is desirable. The thickness of the wing portion 732 is preferably about 50 [μm] to about 500 [μm], more preferably 100 [μm] to 300 [μm].

  As described above, the agitator 73 includes the shaft portion 731, the bone portion 734, and the wing portion 732 as separate members, but may be integrally molded by an injection molding machine using a resin material.

FIG. 7 is a cross-sectional perspective view of a developer storage container 71K for K color.
A first agitator 73a, a second agitator 73b, and a transport screw 72 are installed in the container main body 71A of the developer storage container 71K for K color. The first and second agitators 73a and 73b have the same configuration as the agitator 73 provided in the color developer storage container 71YMC shown in FIG.

FIG. 8 is an enlarged view showing the vicinity of the coupling 74 attachment portion of the K developer storage container 71K.
As shown in FIG. 8, one end of each of the shaft portions 731a and 731b of the agitators 73a and 73b of the K developer storage container 71K is exposed from the container body 71A, and a coupling 74 is provided at the one end. . Further, as shown in FIG. 5, one end of the shaft portion 731 of the agitator of the color developer storage container 71YMC is also exposed from the container main body 71A, and a coupling 74 is provided at this one end.

FIG. 9 is a perspective view illustrating the developer supply driving units 80Y, 80M, 80C, and 80K, and FIG. 10 is a front view of the developer supply driving units 80Y, 80M, 80C, and 80K.
The developer supply drive units 80Y, 80M, 80C, and 80K are drive units that are used when supplying the premix toner in the developer storage container 71 to the sub hoppers 90Y, 90M, 90C, and 90K of the developer supply device. The developer supply driving units 80Y, 80M, 80C, and 80K include an agitator 73 in the developer container 71, a transport screw 72, and first and second agitation transport members 96 in sub hoppers 90Y, 90M, 90C, and 90K, which will be described later. , 97 (see FIG. 12).

  Each developer supply drive unit 80Y, 80M, 80C, 80K includes a supply drive motor 81Y, 81M, 81C, 81K as a second drive source. Each developer supply drive unit 80Y, 80M, 80C, 80K has a gear train composed of a plurality of gears, and the gears constituting the gear train are rotatable to face plates 86Y, 86M, 86C, 86K. It is supported. Further, each of the developer supply driving units 80Y, 80M, 80C, 80K is provided with transport joints 83Y, 83M, 83C, 83K connected to the transport screw 72 of the developer storage container 71. The color developer supply drive units 80Y, 80M, and 80C are provided with drive side couplings 85Y, 85M, and 85C connected to the coupling 74 described above. The K developer supply driving unit 80K is provided with a first drive side coupling 85aK connected to a coupling 74 attached to the shaft portion 731a of the first agitator. A second drive side coupling 85bK connected to the coupling 74 attached to the shaft portion 731b of the second agitator is also provided.

  The driving force of each of the supply drive motors 81Y, 81M, 81C, 81K is transmitted to the transport screw 72 in the developer storage container of each color via the worm gear, the plurality of gears, and the transport joints 83Y, 83M, 83C, 83K. Then, the conveying screw 72 is driven to rotate. Further, the supply drive motors 81Y, 81M, 81C, and the agitator drive gears 84Y, 84M, and 84C and the first agitator drive gear 84aK are further connected to the agitator drive gears 84Y, 84M, and 84C from the transfer joints 83Y, 83M, 83C, and 83K. A driving force of 81K is transmitted. Then, the driving force is transmitted to the agitator 73 via the drive side couplings 85Y, 85M, 85C provided coaxially with the agitator drive gears 84Y, 84M, 84C, and the agitator 73 is rotationally driven. Further, the driving force is transmitted to the first agitator 73a via the first drive side coupling 85aK provided coaxially with the first agitator drive gear 84aK, and the first agitator 73 is driven to rotate. Regarding the K-color developer supply drive unit 80K, the drive force of the supply drive motor 81K is transmitted from the first agitator drive gear 84aK to the second agitator drive gear 54bK. Then, the driving force is transmitted to the second agitator 73b via the second driving side coupling 85bK provided coaxially with the second agitator driving gear 84bK, and the second agitator 73b is rotationally driven.

  Further, the driving force of each of the supply drive motors 81Y, 81M, 81C, 81K is supplied to the supply-side one-way clutch 82Y attached to the rear end portion of the rotary shaft of the first agitating and conveying member 96 (see FIG. 12) described later. 82M, 82C and 82K. Then, the driving force of each of the supply drive motors 81Y, 81M, 81C, 81K is transmitted to the first stirring / conveying member 96 and the second stirring / conveying member 97, which will be described later, via the supply-side one-way clutches 82Y, 82M, 82C, 82K. Is done.

  Next, the sub hoppers 90Y, 90M, 90C, and 90K of the developer supply devices 70Y, 70M, 70C, and 70K will be described. Since the sub-hoppers 90Y, 90M, 90C, and 90K for each color are the same, the K-color sub-hopper will be described here, and the subscripts Y, M, C, and K are omitted as appropriate in the following description. explain.

FIG. 11 is a perspective view showing the configuration of the sub hopper 90, and FIG. 12 is a perspective view showing the internal structure of the sub hopper 90.
As shown in FIGS. 11 and 12, the sub hopper 90 includes a first stirring and conveying member 96, a second agitating and conveying member 97, a first conveying member 98, a second conveying member 99 and a case 93 b opened at the top, An upper cover 93a is provided to close the opening of the case 93b. The upper cover 93 a is formed with a receiving port 91 that receives the premix toner supplied from the supply port of the developer storage container 71.

  As illustrated in FIG. 13, the sub hopper 90 includes a developer storage unit 90 a that temporarily stores the premix toner supplied from the developer storage container 71, and the premix toner stored in the developer storage unit 90 a. A transport unit 90b for transporting to The developer storage unit 90 a and the transport unit 90 b are formed by partitioning the inside of the case with a partition wall 92. As shown in FIG. 12, a first opening 92a and a second opening 92b are formed on the rear side of the partition wall 92, which is the developer supply driving unit side, and on the front side opposite thereto.

  A first agitation transport member 96 and a second agitation transport member 97 are arranged side by side in the developer reservoir 90a. Further, a developer detection sensor 95 for detecting the developer in the developer storage section is provided on the right side wall of the case 93b in the drawing. The developer detection unit of the developer detection sensor 95 is disposed at a predetermined height from the bottom of the case. The first stirring / conveying member 96 disposed on the right side of the developer storage unit 90a in the drawing has a rotating shaft 96c and a helical screw 96b having a large pitch. Further, a cleaning member 96 a for cleaning the developer detecting portion 95 of the developer detecting sensor is provided at a location facing the developer detecting portion of the developer detecting sensor 95 of the first stirring and conveying member 96. Further, the second agitation transport member 97 disposed on the partition wall 92 side of the developer storage section 90a is provided with a spiral screw 97b having a large pitch and a paddle 97a on the rotation shaft 97c. A paddle 96a is provided in a portion of the rotating shaft 97c facing the first opening 92a and a portion facing the second opening 92b. Further, the rear side of the portion of the screw 97b facing the receiving port 91 is shaped so that the premix toner is conveyed to the rear side, and the front side of the portion facing the receiving port is premixed. The shape is such that the toner is conveyed to the front side.

  The transport unit 90b is partitioned into a first transport path 902A and a second transport path 902B by a transport partition wall 901. A transfer opening 901a is formed on the front side of the transfer partition wall 901, and the first transfer path 902A and the second transfer path 902B are communicated with each other. A first transport member 98 is disposed in the first transport path 902A, and a second transport member 99 is disposed in the second transport path 902B. Each conveying member 98, 99 is composed of rotating shafts 98b, 99b and helical screws 98a, 99a. As for the screw 98a of the 1st conveyance member 98, the pitch of the location facing the opening 901a for conveyance is narrower than the other location. The screws 99a of the second conveying member 99 have a constant pitch in the rotation axis direction. The first transport member 98 transports the premix toner in the first transport path 902A toward the transport opening 901a (from the rear side to the front side), and the second transport member 99 pre-loads in the second transport path 902B. The mixed toner is conveyed from the front side to the rear side. A developer replenishment outlet communicating with a replenishment port (not shown) of the developing device 4 is provided at a position located at the developer conveyance downstream end of the second conveyance path 902B on the bottom surface of the case 93b. The premix toner that has been transported through the second transport path 902B by the second transport member 99 is supplied to the developing device 4 from the developer supply outlet.

  Further, the sub hopper 90 is provided with a developer replenishment drive unit 110 used when replenishing the developing device 4 with premix toner. The developer replenishment drive unit 110 is provided on the front side of the sub hopper 90 and includes a replenishment drive motor 111 and a gear train including a plurality of gears. The driving force of the replenishment drive motor 111 is transmitted to the first agitation transport member 96 via the replenishment-side one-way clutch 112 provided at the other end (lower end in the figure) of the rotation shaft 96c of the first agitation transport member 96. The first stirring and conveying member 96 is driven to rotate. Further, the driving force of the replenishment drive motor 111 is transmitted from the first stirring / conveying member 96 to the second stirring / conveying member 97 via a plurality of gears, and the second stirring / conveying member 97 is rotationally driven. In addition, a driving force is transmitted from the replenishment drive motor 111 to the first and second transport members 98 and 99 through a plurality of gears, and the first and second transport members 98 and 99 are rotationally driven.

  In the present embodiment, a developer storage unit 90a is provided, and the premix toner is stored in the developer storage unit 90a. As a result, even if the developer container 71 becomes empty, the toner can be supplied to the developing device 4 for a while with the premix toner stored in the developer storage section 90a. As a result, a good image can be formed while the user prepares a new developer container.

  FIG. 14 is a block diagram illustrating an example of a main configuration of a control system in the developer supply device 70. In FIG. 14, a control unit 210 as a control unit includes a CPU, a ROM 902 that stores a control program and various data, a RAM that temporarily stores various data, and the like. The control unit 210 receives the toner density detection result from the toner density sensor 201 that detects the toner density of the developer in the developing device 4. The controller 210 compares the target value stored in the RAM with the detection result of the toner density sensor, and controls the replenishment drive motor 111 so that the amount of premixed toner corresponding to the comparison result is replenished. The Specifically, the replenishment drive motor 111 is driven for a time corresponding to the replenishment amount. As a result, an appropriate amount of premix toner is supplied from the developer replenishing device 70 to the developer whose toner concentration has decreased due to toner consumption associated with development. As described above, the premix toner has a toner amount of 25 to 35% by weight, which is larger than the toner amount (4 to 10% by weight) of the developer in the developing device. Therefore, by supplying the premix toner into the developing device, the toner concentration of the developer in the developing device increases, and the toner concentration of the developer in the developing device 4 is maintained near the target value.

  When the control unit 210 detects that the premix toner in the developer storage unit 90a is less than a predetermined amount based on a signal from the developer detection sensor 95, the control unit 210 drives the supply drive motor 81 to receive the receiving port 91. The premix toner is supplied via When the control unit 210 detects that the premix toner in the developer storage unit 90a is equal to or larger than a predetermined amount based on a signal from the developer detection sensor 95, the control unit 210 stops driving the supply drive motor 81 and performs premixing. The toner supply is terminated. In addition, when the signal from the developer detection sensor 95 does not change even when the supply drive motor 81 is driven for a predetermined time (12 seconds in this embodiment), the control unit 210 supplies the supply drive motor 81. Stop driving. Then, assuming that there is no premixed toner in the developer storage container, a display to the effect that the developer storage container 71 is to be replaced is displayed on a display unit (not shown) of the main body of the image forming apparatus.

Next, the movement of the premix toner in the sub hopper 90 will be described.
FIG. 15 is a diagram illustrating the movement of the premix toner when the developer is supplied from the developer storage container 71 to the developer storage unit 90a.
As shown in FIG. 15, when the premix toner is supplied from the developer storage container 71 to the developer storage section 90a, the supply drive motor 81 is driven as described above. When the supply drive motor 81 is driven, the first stirring / conveying member 96 and the second stirring / conveying member 97 are rotationally driven via the supply-side one-way clutch 82. At this time, the rotation shaft of the first agitating / conveying member 96 idles with respect to the supply side one-way clutch 112, and the supply side one-way clutch 112 does not rotate. The first and second agitating and conveying members 96 and 97 rotate clockwise as viewed from the front side.

  The premix toner in the developer storage container 71 is supplied onto the second stirring and conveying member 97 of the developer storage unit 90a. The premix toner supplied onto the second agitating / conveying member 97 is conveyed to the front side and the rear side by the second agitating / conveying member 97. The premix toner conveyed to the rear end by the second agitating / conveying member 97 is sent to the conveying unit 90b through the first opening 92a. At this time, since the transport members 98 and 99 of the transport unit 90b are stopped, the premix toner accumulates in the vicinity of the first opening 92a of the transport unit 90b. If the premix toner cannot be conveyed to the conveyance unit 90b by the accumulated premix toner, the premix toner conveyed to the rear end is conveyed to the first agitation conveyance member side. The premix toner conveyed to the front end by the second agitating and conveying member 97 is sent to the conveying unit 90b through the second opening 92b. When the premix toner accumulated near the second opening 92b of the transport unit 90b cannot be transported to the transport unit 90b, the premix toner transported to the front end is also transported to the first stirring transport member side.

  The first agitation and conveyance member 96 conveys the premixed toner toward the detection area of the developer detection sensor 95 as shown in the drawing. The premix toner conveyed to the detection area of the developer detection sensor 95 is conveyed directly below the receiving port 91 by the paddle-shaped cleaning member 96a. In this way, when the premix toner is supplied from the developer storage container 71 to the developer reservoir 90a, the premix toner is circulated in the developer reservoir 90a by the first and second agitation transport members 96 and 97. To do.

  In this embodiment, when the premix toner is supplied from the developer storage container 71 to the developer storage unit 90a, only the supply drive motor 81 is driven to drive the agitator 73, the transport screw 72, the first and second. The agitating and conveying members 96 and 97 are driven. Thereby, the power consumption when supplying the premix toner from the developer storage container 71 to the developer storage section 90a can be reduced as compared with the following case. That is, the first and second agitating and conveying members are driven by the replenishing drive motor 111 and the agitator 73 and the conveying screw 72 are driven by the supplying drive motor 81.

  Further, when the premix toner is supplied from the developer storage container 71 to the developer storage section 90a, the replenishment drive motor 111 is stopped. Thereby, the lifetime of the replenishment drive motor 111 can be extended. The replenishment drive motor 111 uses an expensive stepping motor because it is necessary to replenish the developing device 4 with the premix toner with high accuracy. Therefore, the maintenance cost can be reduced by extending the life of the replenishment drive motor 111.

FIG. 16 is a diagram illustrating the movement of the premix toner when the premix toner is supplied to the developing device 4.
When the premix toner is replenished to the developing device 4, the replenishment drive motor 111 is driven. When the replenishment drive motor 111 is driven, the first and second agitation transport members 96 and 97 and the first and second transport members 98 and 99 are rotationally driven. The first and second agitating and conveying members 96 and 97 and the first conveying member 98 rotate clockwise when viewed from the front side, and the second conveying member 99 rotates counterclockwise when viewed from the front side. The first transport member 98 transports the premix toner in the first transport path 902A from the rear side to the front side. Then, the premix toner conveyed to the front end is sent to the second conveyance path 902B through the conveyance opening 901a by the first conveyance member 98. The premix toner sent to the second conveyance path 902B is conveyed from the front side to the rear side by the second conveyance member 99, and when it is conveyed to the rear end, it drops from the replenishing port and is replenished to the developing device 4. Is done.

  Further, the premix toner in the developer storage unit 90a is conveyed in the same manner as described above. However, since the first conveying member 98 and the second conveying member 99 are rotationally driven during the replenishment of the developer, the premix toner is not collected in the vicinity of the first and second openings 92a and 92b of the conveying unit 90b. Instead, it is being transported. For this reason, the premix toner in the developer reservoir 90a does not circulate in the developer reservoir 90a, but is sequentially delivered to the transport unit 90b.

  As described above, the premix toner in the developer storage section 90a is sequentially transferred from the first and second openings 92a and 92b to the transport section 90b, thereby reducing the amount of premix toner in the developer storage section 90a. I will do it. As a result, the height of the premix toner is lower than the developer detection portion of the developer detection sensor 95, and the developer detection sensor 95 does not detect the premix toner. Then, the supply drive motor 81 is driven to start supplying the premix toner to the developer storage unit 90a. When the supply drive motor 81 is driven, a driving force is transmitted to the supply-side one-way clutch 82, and the supply-side one-way clutch 82 rotates. In the present embodiment, the rotational speed of the supply-side one-way clutch 82 is faster than the rotational speed of the first stirring and conveying member 96 that is rotated by the replenishment drive motor 111. Before the supply-side one-way clutch 82 rotates, the rotation direction of the rotation shaft of the first stirring / conveying member 96 relative to the supply-side one-way clutch 82 is clockwise as viewed from the front side. However, when the supply-side one-way clutch 82 rotates, the rotation direction of the rotation shaft of the first stirring / conveying member 96 relative to the supply-side one-way clutch 82 becomes counterclockwise when viewed from the front side. As a result, the supply-side one-way clutch 82 is connected, and the first and second stirring and conveying members 96 and 97 are rotated by the driving force of the supply driving motor 81. When the first stirring / conveying member 96 starts to rotate by the driving force of the supply drive motor 81, the rotational speed of the rotation shaft of the first stirring / conveying member 96 becomes faster than the rotational speed of the replenishment-side one-way clutch 112. As a result, the rotation shaft of the first agitating and conveying member 96 idles with respect to the replenishment-side one-way clutch 112. The first and second transport members 98 and 99 are continuously driven to rotate by the replenishment drive motor 111.

  Thus, by making the rotational speed of the first agitation transport member 96 by the supply drive motor 81 different from the rotational speed of the first agitation transport member 96 by the replenishment drive motor 111, an inexpensive one-way clutch, The drive source can be switched. In addition, when the drive source is switched using an electromagnetic clutch or the like, it is necessary to control the timing for engaging the clutch. However, in this embodiment, since it is not necessary to control the timing of engaging such a clutch, there is also an advantage that the software configuration can be simplified.

  Further, since the first and second agitating / conveying members can be driven by the replenishment drive motor 111, the supply drive motor 81 can be stopped when the premix toner is replenished to the developing device 4. . As a result, the power consumption when the premix toner is supplied to the developing device 4 is supplied to the first and second agitating and conveying members 96 and 97 by the supply driving motor 81 and the first and second conveying members 98 and 97 by the supplying drive motor. This can be reduced as compared with the case of supplying 99 by driving 99.

FIG. 17 is a diagram for explaining the movement of the premix toner when the replenishment operation to the developing device 4 and the supply operation to the developer storage unit 90a are performed simultaneously.
As shown in FIG. 17, when the premix toner is supplied through the receiving port 91, the amount of the premix toner conveyed to the second stirring and conveying member 97 to the vicinity of the first and second openings 92a and 92b. Will increase. Accordingly, premixed toner that cannot move to the conveyance unit 90b is generated, and these move to the first agitation conveyance member side and circulate in the developer storage unit.

  As described above, in this embodiment, when the premix toner in the developer storage unit 90a becomes less than a predetermined amount when the premix toner is supplied to the developing device 4, the developer storage container 71 to the developer storage unit 90a. Is supplied with a developer. A constant amount of premix toner can always be transferred to the transport unit 90b. Thereby, the height of the premix toner in the conveyance unit 90b can be kept constant. Since the agent conveying ability of the first and second conveying members 98 and 99 is determined by the shape of the screw and the height of the agent around the screw, by keeping the height of the premix toner in the conveying unit 90b constant, Variations in the replenishment amount per unit time to the developing device 4 can be suppressed.

  In the present embodiment, the supply side one-way clutch 112 is provided at the front end portion of the rotation shaft of the first agitating and conveying member 96, and the supply side one-way clutch 82 is provided at the rear end portion. Side and supply side one-way clutches 82 and 112 are provided. When the clutch is engaged, the torque changes abruptly, which may cause twisting of the rotating shaft. In order to prevent such twisting, the shaft to which the one-way clutch is attached needs to be hardened such as quenching. By providing the replenishment-side one-way clutch 112 and the supply-side one-way clutch 82 on the rotation shaft of the first stirring / conveying member 96, the shaft for high hardness processing can be limited to the rotation shaft of the first stirring / conveying member 96. it can. Thereby, cost reduction of an apparatus can be achieved.

  The toner just before the developer container 71 becomes empty is agitated by the agitator 73 for a long time and deteriorated. In the case where there is only one delivery location to the transport unit 90b, delivery is performed to the transport unit 90b only from the one delivery location. Therefore, even if the developer container 71 is replaced and new toner is supplied to the developer storage unit 90a, the new toner is not transferred until the deteriorated old toner in the transport unit 90b is transported. It is not transported to 90b. In addition, the new toner and the old toner are hardly mixed in the transport unit 90b. Accordingly, there is a possibility that the image is deteriorated because the deteriorated old toner is supplied to the developing device 4 for a while after the developer container 71 is replaced.

  On the other hand, in the present embodiment, the premix toner in the developer storage unit 90a is delivered to the transport unit 90b at two locations, the front end and the rear end. As a result, the premix toner in the developer storage section 90a is delivered to the conveyance opening 901a that is a communication point between the first conveyance path 902A and the second conveyance path 902B. As a result, when the developer storage container 71 is replaced and new toner is supplied to the developer storage section 90a, the new toner is delivered at the communication point between the first transport path 902A and the second transport path 902B. And mixed with old degraded toner. As a result, the toner replenished to the developing device 4 after the developer container 71 is replaced becomes a mixture of old toner and new toner, and image deterioration can be suppressed.

  Also, until the developer storage container 71 is empty and replaced with a new developer storage container 71, the premix toner in the developer storage section 90a is transferred to the transport section 90b, whereby the developer The amount of premix toner in the reservoir is decreasing. As a result, the amount delivered from the developer storage unit 90a to the transport unit 90b decreases. When there is only one delivery point to the transport unit 90b, the amount of premix toner in the first transport path 902A is restored even if the developer storage container is replaced and the premix toner amount in the developer storage unit is restored. The portion where the decrease is not recovered to the desired amount on the way. Accordingly, the replenishment amount to the developing device 4 is not stable for a while after the replacement with the developer storage container 71. On the other hand, as in this embodiment, the pre-mix toner in the developer reservoir 90a is delivered to the transport unit 90b at two locations, the front end and the rear end, so that the first transport is performed. Even if there is a portion in the path 902A where the amount of the premix toner has decreased, it can be recovered at the communication point between the first transport path 902A and the second transport path 902B. Therefore, the amount of replenishment to the developing device 4 can be stabilized even after replacement with the developer storage container 71.

  In the present embodiment, a sub hopper 90 is provided directly above the developing device 4, and the sizes of the sub hoppers 90 for the respective colors are the same. On the other hand, as described above with reference to FIGS. 4 and 5, the developer storage container 71 disposed immediately above the sub hopper 90 is not the same for each color, and the K color developer storage container is a color developer. It is larger than the storage container. For this reason, the position of the supply port for supplying the premix toner to the sub hopper 90 of the developer storage container is different for each color. As a result, as shown in FIG. 9, the positions of the receiving ports 91Y, 91M, 91C, 91K of the sub-hoppers of the respective colors provided to face the supply port are also different. In this embodiment, the distance from the developer detection sensor 95 to the receiving port 91 where the premix toner is supplied is about 14 mm for K color, about 28 mm for C color, and about 24 mm for M color. The Y color is about 20 mm. Thus, in the present embodiment, the C-color or M-color receiving port 91 is provided at a position away from the developer detection sensor 95. In another image forming apparatus, a K-color receiving port 91 </ b> K is disposed in the vicinity of the developer detection sensor 95.

  Conventionally, when the premix toner is supplied from the supply port of the developer container, the agitating / conveying members 96 and 97 of the developer storing portion 90a are not driven. As described above, when the premix toner is supplied, if the agitating and conveying members 96 and 97 of the developer reservoir 90a are not driven, the receiving port 91 is in the vicinity of the developer detection sensor 95 or in a position away from it. If so, the following problems will occur.

FIG. 18 is a diagram for explaining a conventional defect. FIG. 18A is a diagram for explaining a conventional problem when the receiving port 91 is in the vicinity of the developer detection sensor 95, and FIG. 18B is a diagram illustrating that the receiving port 91 is separated from the developer detection sensor 95. It is a figure explaining the conventional malfunction when it exists in the position.
When the premix toner is supplied from the receiving port 91, when the agitating and conveying members 96 and 97 of the developer storing unit 90 a are not driven, the premixed toner supplied from the receiving port 91 to the developer storing unit 90 a by free fall. The mixed toner is deposited near the receiving port. Accordingly, the height of the premix toner T in the vicinity of the receiving port is higher than in other portions.

  As shown in FIG. 18A, when the receiving port 91 is in the vicinity of the developer detection sensor 95, the developer detection sensor 95 is moved before the desired amount of premix toner T is accumulated in the developer storage section 90a. Detect premix toner. Accordingly, the premix toner in the developer reservoir 90a is less than the desired amount, and the amount of toner delivered from the developer reservoir 90a to the transport unit 90b is reduced when the developer is replenished. As a result, the amount of toner transported by the transport members 98 and 99 of the transport section 90b is also reduced, the replenishment amount per unit time to the developing device 4 is less than the desired amount, and the image density is reduced. Arise. Further, since the amount of premix toner temporarily stored in the developer storage unit 90a is reduced, the premix toner in the developer storage unit is quickly lost after the developer storage unit 90a is emptied. The premix toner cannot be supplied. Therefore, it is necessary to stop the image forming operation before the new developer container 71 is replaced, and there is a possibility that the downtime of the apparatus may occur.

  Further, as shown in FIG. 18B, when the receiving port 91 is arranged at a position away from the developer detection sensor 95, the developer detection sensor 95 does not stop even if a desired amount is accumulated in the developer storage section 90a. Premix toner cannot be detected. As a result, the premix toner overflows from the receiving port 91 and closes the receiving port 91. As a result, a problem such as premix toner clogging occurs at the location where the conveying screw 72 of the developer container 71 is disposed. In particular, when the amount of premix toner in the developer reservoir 90a is small, such as after replacement of the developer storage container 71, the above problem is likely to occur.

  In particular, in the present embodiment, a toner having an outflow temperature with poor fluidity of 90 ° C. or less is used as the toner. Therefore, the mountain does not easily spread when deposited on the developer reservoir 90a by free fall. Therefore, the problem shown in FIGS. 18A and 18B is likely to occur. Further, even in an environment where the fluidity of the toner is lowered, such as the environmental temperature and humidity around the sub hopper, the mountain is difficult to spread, and the problems shown in FIGS. 18A and 18B are likely to occur.

  On the other hand, in the present embodiment, when the premix toner is supplied from the receiving port 91 to the developer storage section 90a, the first stirring / conveying member 96 and the second stirring / conveying member 97 are driven to rotate, as shown in FIG. As shown in FIG. 2, the premix toner is circulated in the developer reservoir 90a. As a result, the premix toner supplied to the developer storage unit 90a is conveyed and diffused. Thereby, it is possible to suppress the premic toner supplied in the vicinity of the receiving port from accumulating in a mountain shape, and the amount of the premix toner is equalized in the developer reservoir 90a. As a result, as shown in FIG. 19, even if the receiving port 91 is disposed in the vicinity of the developer detection sensor 95, the developer detection sensor after the desired amount of premix toner is stored in the developer storage section 90a. 95 detects premix toner. Accordingly, when the developer is replenished, a desired amount of premix toner can be transferred from the developer storage unit 90a to the conveyance unit 90b, and the toner amount of the conveyance unit 90b can be suppressed from decreasing. Accordingly, a desired amount of premix toner can be supplied to the developing device 4.

  Even when the receiving port 91 is disposed at a position away from the developer detection sensor 95, the developer detection sensor 95 detects the premix toner when a desired amount of premix toner is stored in the developer storage section 90a. To do. Thereby, it is possible to prevent a problem that the premix toner is clogged at the position where the conveying screw 72 of the developer container 71 is disposed.

  Further, in the sub hopper 90, since the position of the receiving port 91 is different for each color, it is necessary to provide the upper cover 93a for each color, which increases the number of parts and leads to an increase in the cost of the apparatus. Therefore, as shown in FIG. 20, the receiving port 91 of the upper cover 93 a may have a rectangular shape extending in the direction in which the developer storage containers 71 are arranged. As a result, even if the positional relationship between the sub hopper 90 and the supply port of the developer container 71 is different from each other in the direction in which the developer container 71 is arranged, the common upper cover can cope with it. Thereby, based on the positional relationship between the sub hopper 90 and the supply port of the developer container 71, the number of parts can be reduced and the apparatus can be made cheaper than when the upper cover 93a is prepared for each color. Can do.

What has been described above is an example, and the present invention has a specific effect for each of the following aspects.
(Aspect 1)
A developer storage container 71 that stores a developer such as a premix toner, a developer storage section 90 a that temporarily stores the developer supplied from the developer storage container 71, and a transport member therein, and a developer A transport unit 90b that transports the developer stored in the storage unit 90a to the developing device, and a stirrer that is provided in the developer storage unit and stirs the developer in the developer storage unit and transports the developer to the transport unit. A replenishment drive source such as a replenishment drive motor 111 that drives the transport member and the agitation transport member when replenishing the developer to the developing device 4 and a bottom surface of the developer reservoir 90a are separated from each other by a predetermined distance. A developer detection means such as a developer detection sensor 95 for detecting the developer at the position; a supply member such as a transport screw 72 for supplying the developer in the developer storage container to the developer storage portion 90a from the supply port; A developer supply device comprising a supply drive source such as a supply drive motor 81 for driving the material and a control means such as a control unit 210 for controlling the supply drive source based on the detection result of the developer detection means. In 70, the stirring and conveying member is configured to be driven by a supply source for supply.
By providing such a configuration, as described in the embodiment, the number of driving sources to be driven can be suppressed. As a result, the power consumption during the supply operation for supplying the developer in the developer storage container to the developer storage unit Can be suppressed.

(Aspect 2)
In (Aspect 1), when the developer is supplied from the developer storage container 71 to the developer storage section 90a, the agitation transport member is driven.
With this configuration, as described in the embodiment, a desired amount of developer is supplied to the developer reservoir 90a regardless of the positional relationship between the supply port and the developer detection means such as the developer detection sensor 95. The developer can be stored and the developer can be prevented from overflowing from the supply port.

(Aspect 3)
In (Aspect 1) or (Aspect 2), the drive transmission path from the replenishment drive source such as the replenishment drive motor 111 to the agitation transport member and the supply drive source such as the supply drive motor 81 to the agitation transport member A clutch is provided on at least one of the drive transmission paths.
With this configuration, by switching the clutch, the agitation transport member can be driven by the supply drive motor 81 during the supply operation, and when the developer is supplied to the developing device 4, the supply drive motor is supplied. The stirring and conveying member can be driven by a replenishing drive source such as 111.

(Aspect 4)
In (Aspect 3), a one-way clutch was used as the clutch.
With such a configuration, the device can be made cheaper than when an electromagnetic clutch or the like is used.

(Aspect 5)
Further, in (Aspect 4), the agitating / conveying member rotates by itself to convey the developer, and the drive transmission and supply from the supply driving source such as the supplying drive motor 81 to the agitating / conveying member. The drive transmission from the replenishment drive source such as the drive motor 111 to the stirring and conveying member is performed via a one-way clutch, and the rotational speed of the stirring and conveying member by the supply drive source is determined by the supply drive source. The rotational speed of the agitating and conveying member due to was increased.
By providing such a configuration, as described in the embodiment, the drive source of the agitation transport member can be switched using an inexpensive one-way clutch as described in the embodiment.

(Aspect 6)
Further, in (Aspect 5), a one-way clutch 82 for transmitting the driving force of a supply source for supply such as a supply drive motor 81 to the stirring and conveying member is provided at one end of the rotating shaft of the stirring and conveying member, and the replenishing drive A one-way clutch 112 for transmitting the driving force of a replenishing drive source such as a motor 111 to the stirring and conveying member is provided at the other end of the rotating shaft of the stirring and conveying member.
By providing such a configuration, as described in the embodiment, the shaft for increasing the hardness can be only the rotating shaft of the stirring and conveying member, and the apparatus can be made inexpensive.

(Aspect 7)
In (Aspect 1) to (Aspect 6), the agitating / conveying members 96 and 97 and the conveying members 98 and 99 rotate by themselves to convey the developer, and the agitating / conveying members 96 and 97 and the conveying member 98 are rotated. , 99 are arranged so that their rotational axes are positioned in parallel with each other on the same virtual plane, and the partition wall extends between the agitating and conveying members 96, 97 and the conveying members 98, 99 in the direction of the rotational axis of the conveying member. The partition forms a developer storage section 90a and a transport section 90b, and openings 92a and 92b through which the developer is transferred from the developer storage section 90a to the transport section 90b are provided at both ends in the rotation axis direction of the transport member of the partition wall. It was.
With this configuration, the developer in the developer storage unit 90a can be efficiently transferred to the transport unit 90b.

(Aspect 8)
In any one of (Aspect 1) to (Aspect 7), a plurality of stirring and conveying members are provided.
With this configuration, as described in the embodiment, the developer in the developer storage unit 90a can be efficiently circulated and conveyed, and the height of the developer in the developer storage unit 90a when the developer is supplied. Can be made uniform uniformly.

(Aspect 9)
In any one of (Aspect 1) to (Aspect 8), a developer having a toner having an outflow temperature of 90 ° C. or lower is supplied to the developing device 4.
As described in the embodiment, even when toner having an outflow temperature of 90 ° C. or less is used, the developer storage section 90a is independent of the positional relationship between the supply port 91 and the developer detection means such as the developer detection sensor 95. Thus, a desired amount of developer can be stored, and the developer can be prevented from overflowing from the supply port 91.

(Aspect 10)
Further, an image forming apparatus including means for forming a latent image on an image carrier such as a photosensitive member (comprising a charger and an optical writing unit 21) and a developing device 4 that supplies toner to the latent image and develops it. In the apparatus, as a developer replenishing means for replenishing the developer to the developing device 4, the developer replenishing apparatus of any one of (Aspect 1) to (Aspect 9) is employed.
By providing such a configuration, as described in the embodiment, a desired amount of developer can be stably supplied to the developing device 4, and a good image can be obtained.

(Aspect 11)
Further, in (Aspect 10), the apparatus includes a plurality of developing devices and a plurality of developer replenishing devices provided corresponding to the developing devices, the supply port of at least one developer replenishing device, and developer detection The positional relationship with the developer detection means such as the sensor 95 is different from other developer supply devices.
Even if the positional relationship between the supply port 91 and the developer detection means such as the developer detection sensor 95 is different from each other as in this configuration, the developer supply device having the same configuration can be used to stably supply a desired developer. The developing device 4 can be replenished. Thereby, the cost of the image forming apparatus can be reduced.

(Aspect 12)
Further, in (Aspect 11), the shape of the developer storage container of at least one developer supply device is made different from the shapes of the other developer storage containers.
By providing such a configuration, as described in the embodiment, it is possible to use a developer storage container corresponding to the consumption speed of the developer, and it is necessary to frequently replace the developer storage container having a high developer consumption speed. It is possible to eliminate problems such as

1: Photoconductor 4: Developing device 21: Optical writing unit 70: Developer replenishing device 71: Developer storage container 71A: Container body 72: Transport screw 73: Agitator 73a: First agitator 73b: Second agitator 74: Cup Ring 77: container holding unit 80: developer supply drive unit 81: supply drive motor 82: supply side one-way clutch 90: sub hopper 90a: developer storage unit 90b: transport unit 91: supply port 92: partition wall 92a: first Opening 92b: Second opening 93a: Upper cover 93b: Case
95: Developer detection sensor 96: First agitating and conveying member 96a: Cleaning member 97: Second agitating and conveying member 98: First conveying member 99: Second conveying member 110: Developer replenishing drive unit 111: Replenishing drive motor 112 : Replenishment-side one-way clutch 210: Control unit 901: Conveying partition wall 901 a: Conveying opening 902 A: First conveying path 902 B: Second conveying path

JP 2010-256758 A

Claims (13)

A developer container containing the developer;
A developer storage section for temporarily storing the developer supplied from the developer storage container;
A transport unit that includes a transport member therein, and transports the developer stored in the developer storage unit to the developing device;
An agitating and conveying member that is provided in the developer storing portion, stirs the developer in the developer storing portion, and conveys the developer to the conveying portion;
A replenishment drive source that drives the transport member and the agitation transport member when replenishing the developer to the developing device;
Developer detecting means disposed at a position away from the bottom surface of the developer storing portion by a predetermined distance;
A supply member for supplying the developer in the developer storage container from the supply port to the developer storage section;
A drive source for supply for driving the supply member;
A developer replenishing device comprising a control means for controlling the drive source for supply based on a detection result of the developer detecting means;
The stirring and conveying member is configured to be driven by the supply source for supply ,
The agitating and conveying member and the conveying member rotate by themselves to convey the developer,
The partition between the stirring and conveying member and the conveying member extends in the direction of the rotation axis of the conveying member to form the developer storage portion and the conveying portion.
2. A developer supply device according to claim 1, wherein openings are provided at both ends of the partition wall in the direction of the rotation axis of the transport member so that the developer is transferred from the developer storage section to the transport section . The developer supply device according to claim 1 .
A developer replenishing device, wherein a clutch is provided in at least one of a drive transmission path from the replenishment drive source to the agitation transport member and a drive transmission path from the supply drive source to the agitation transport member. The developer supply device according to claim 2 .
A developer replenishing device using a one-way clutch as the clutch. The developer replenishing device according to claim 3 .
The stirring and conveying member is rotated by itself to convey the developer,
Drive transmission from the supply drive source to the stirring and conveying member and drive transmission from the replenishment drive source to the stirring and conveying member are each performed via a one-way clutch,
The developer replenishing device, wherein a rotation speed of the agitating / conveying member by the supply driving source is higher than a rotation speed of the agitating / conveying member by the replenishing driving source. The developer replenishing device according to claim 4 .
A one-way clutch for transmitting the driving force of the supply driving source to the stirring and conveying member is provided at one end of the rotating shaft of the stirring and conveying member, and the driving force of the replenishing driving source is transmitted to the stirring and conveying member. A developer replenishing device, wherein a one-way clutch is provided at the other end of the rotating shaft of the stirring and conveying member.   A developer container containing the developer;
A developer storage section for temporarily storing the developer supplied from the developer storage container;
A transport unit that includes a transport member therein, and transports the developer stored in the developer storage unit to the developing device;
An agitating and conveying member that is provided in the developer storing portion, stirs the developer in the developer storing portion, and conveys the developer to the conveying portion;
A replenishment drive source that drives the transport member and the agitation transport member when replenishing the developer to the developing device;
Developer detecting means disposed at a position away from the bottom surface of the developer storing portion by a predetermined distance;
A supply member for supplying the developer in the developer storage container from the supply port to the developer storage section;
A drive source for supply for driving the supply member;
A developer replenishing device comprising a control means for controlling the drive source for supply based on a detection result of the developer detecting means;
The stirring and conveying member is configured to be driven by the supply source for supply,
The stirring and conveying member is rotated by itself to convey the developer,
Drive transmission from the supply drive source to the stirring and conveying member and drive transmission from the replenishment drive source to the stirring and conveying member are each performed via a one-way clutch,
A one-way clutch for transmitting the driving force of the supply driving source to the stirring and conveying member is provided at one end of the rotating shaft of the stirring and conveying member, and the driving force of the replenishing driving source is transmitted to the stirring and conveying member. A developer replenishing device, wherein a one-way clutch is provided at the other end of the rotating shaft of the stirring and conveying member.   The developer replenishing device according to claim 6.
The developer replenishing device, wherein a rotation speed of the agitating / conveying member by the supply driving source is higher than a rotation speed of the agitating / conveying member by the replenishing driving source.   The developer supply device according to any one of claims 1 to 7,
The developer replenishing device, wherein the agitating and conveying member is driven when the developer is supplied from the developer container to the developer reservoir. The developer supply device according to any one of claims 1 to 8 ,
A developer replenishing device comprising a plurality of the agitating and conveying members. The developer supply device according to any one of claims 1 to 9 ,
A developer replenishing device, wherein the developer having toner having an outflow temperature of 90 ° C. or less is replenished to the developing device . In an image forming apparatus comprising a means for forming a latent image on an image carrier and a developing device for supplying toner to the latent image and developing the latent image,
Image forming apparatus characterized by a developer replenishing means for replenishing the developer to the developing device, employing one of the developer supplying apparatus according to claim 1 to 10. The image forming apparatus according to claim 11 .
A plurality of developing devices;
A plurality of developer replenishing devices provided corresponding to each developing device,
An image forming apparatus, wherein a positional relationship between the supply port of at least one developer supply device and the developer detection unit is different from that of other developer supply devices. The image forming apparatus according to claim 12 .
An image forming apparatus, wherein a shape of a developer storage container of at least one developer supply device is different from a shape of another developer storage container.

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