JP5955287B2 - Developing device and image forming apparatus - Google Patents

Description

  The present invention relates to a developing device in which storage chambers for storing a developer are provided above and below, and an image forming apparatus including the developing device.

  2. Description of the Related Art Conventionally, a tandem type color image forming apparatus in which a plurality of image forming units including developing devices corresponding to respective colors are arranged along a transfer belt conveyance direction is known. In this color image forming apparatus, a toner image of each color is formed on the transfer belt by an image forming unit corresponding to each color. Specifically, in the color image forming apparatus, a plurality of toner images are superimposed on a transfer belt to form a color image. In the tandem color image forming apparatus, since the plurality of image forming units are arranged along the transfer belt conveyance direction, the size of the apparatus increases in the transfer belt conveyance direction. For this reason, various devices for reducing the size of the tandem color image forming apparatus in the transport direction have been proposed.

  For example, in order to reduce the size of the image forming unit and the image forming apparatus, a so-called vertical developing device is known in which two toner storage chambers are arranged in the vertical direction and are downsized in the transfer belt conveyance direction. (See Patent Document 1 and Patent Document 2). Patent Document 1 discloses a technique for pulling up toner from a lower toner storage chamber to an upper toner storage chamber by rotation of a magnet roller. In Patent Document 2, the developer is pushed up from the lower toner accommodating chamber to the upper toner accommodating chamber by the conveying force of the conveying member in the lower toner accommodating chamber, and the upper force is increased by the conveying force of the conveying member in the upper toner accommodating chamber. A technique is disclosed in which toner is circulated and conveyed in a developing device by dropping toner from the toner storage chamber to a lower toner storage chamber.

JP 2001-109264 A JP 2002-6599 A

  However, the developing device of Patent Document 1 has a problem that the developer deteriorates due to excessive force when the developer moved upward by the magnet roller is peeled off from the magnet roller, and the entire device is provided with the magnet roller. There are problems such as complications. In the developing device of Patent Document 2, a communication portion where the toner moves from the lower toner storage chamber to the upper toner storage chamber becomes an obstacle, and the toner tends to accumulate near the communication portion in the lower toner storage chamber. There is a risk that it will not be circulated smoothly.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a developing device in which storage chambers for storing a developer are provided above and below, while having a simple configuration, from a lower storage chamber. An object of the present invention is to provide a developing device and an image forming apparatus capable of smoothly moving a developer to an upper storage chamber.

  A developing device according to one aspect of the present invention includes a developer container, a first communication unit, a second communication unit, a first transport unit, a second transport unit, a developer carrier, and a first magnetic force generation unit. The developer container includes a first storage chamber in which the developer is stored and a second storage chamber that is provided below the first storage chamber via a partition wall and in which the developer is stored. The first communication portion is formed in the partition and has a first hole that communicates between the first storage chamber and the second storage chamber. The second communication part is formed at a position spaced apart from the first communication part in the predetermined direction in the partition wall, and has a second hole communicating between the first storage chamber and the second storage chamber. The first transport unit is provided in the first storage chamber and transports the developer from the first hole toward the second hole. The second transport unit is provided in the second storage chamber and transports the developer from the second hole toward the first hole. The developer carrier is provided above the developer container, and adsorbs the developer contained in the first accommodation chamber to the surface by magnetic force. The first magnetic force generator is provided inside the developer carrier, and a magnetic pole for generating the magnetic force is directed toward the first hole.

  An image forming apparatus according to another aspect of the present invention includes the developing device.

  According to the present invention, in the developing device in which the storage chambers for storing the developer are provided above and below, the developer can be smoothly moved from the lower storage chamber to the upper storage chamber.

1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. The figure which shows the structure of an image formation part. FIG. 3 is a diagram illustrating a configuration of a developing device. The figure which shows the cross section of the cutting line IV-IV in FIG. The figure which shows the cross section of the cutting line VV in FIG.3 and FIG.4. The figure which shows the cross section of the cutting line VI-VI in FIG.3 and FIG.4.

  Embodiments of the present invention will be described below with reference to the drawings as appropriate. In addition, the following embodiment is only an example which actualized this invention, and does not limit the technical scope of this invention.

[Image forming apparatus 10]
First, a schematic configuration of an image forming apparatus 10 (an example of the image forming apparatus of the present invention) according to an embodiment of the present invention shown in FIG. 1 will be described. For convenience of explanation, the vertical direction is defined as the vertical direction 8 in the installation state (state shown in FIG. 1) in which the image forming apparatus 10 is installed, and the surface shown in FIG. A front-rear direction 7 is defined as (front), and a left-right direction 9 is defined with reference to the front of the image forming apparatus 10 in the installed state.

  The image forming apparatus 10 is a so-called tandem color image forming apparatus, and includes a plurality of image forming units 4, an intermediate transfer belt 5, a driving roller 6A, a driven roller 6B, a secondary transfer device 20, a fixing device 16, and a paper feed tray. 17, a paper discharge tray 18, a control unit 71, and the like. A specific example of the image forming apparatus 10 according to the embodiment of the present invention is, for example, a printer, a copying machine, a facsimile, or a multifunction machine having these functions.

  In the present embodiment, four image forming units 4 are provided. Each image forming unit 4 (4B, 4Y, 4C, 4M) forms a toner image of a different color on the photosensitive drum 11 provided in each image forming unit 4, and the toner image is in the middle of running (moving). This is an electrophotographic image forming unit that sequentially superimposes and transfers the image onto the transfer belt 5. In the example shown in FIG. 1, the image forming unit 4B for black, the image forming unit 4Y for yellow, the image forming unit 4C for cyan, in order from the downstream side in the moving direction (arrow 19 direction) of the intermediate transfer belt 5; The magenta image forming units 4M are arranged in a line in that order.

  As shown in FIG. 2, the image forming unit 4 includes a photosensitive drum 11, a charging device 12, an optical scanning device 13, a developing device 14 (an example of the developing device of the present invention), a primary transfer device 15, a cleaning device 21, And a static eliminator 22 and the like. The photosensitive drum 11 carries a toner image, and is formed in a cylindrical shape that is long in the front-rear direction 7 (perpendicular to the paper surface). The charging device 12 charges the surface of the photosensitive drum 11. The optical scanning device 13 forms an electrostatic latent image by scanning the surface of the charged photosensitive drum 11 while irradiating laser light. The developing device 14 develops the electrostatic latent image on the photosensitive drum 11 with toner. The cleaning device 21 removes the residual toner image on the photosensitive drum 11. The neutralization device 22 neutralizes the surface of the photosensitive drum 11.

  As shown in FIG. 1, the intermediate transfer belt 5 is supported by a driving roller 6A and a driven roller 6B so as to be rotationally driven. By being supported by the driving roller 6 </ b> A and the driven roller 6 </ b> B, the intermediate transfer belt 5 can move (run) while the surface thereof is in contact with the surface of each photosensitive drum 11. Then, when the surface of the intermediate transfer belt 5 passes between the photosensitive drum 11 and the primary transfer device 15, toner images are sequentially superimposed and transferred from the photosensitive drums 11.

  The secondary transfer device 20 transfers the toner image transferred to the intermediate transfer belt 5 onto the printing paper conveyed from the paper feed tray 17. The printing paper on which the toner image has been transferred is conveyed to the fixing device 16 by a conveying unit (not shown). The fixing device 16 includes a heating roller 16A heated to a high temperature, and a pressure roller 16B disposed to face the heating roller 16A. The printing paper conveyed to the fixing device 16 is conveyed while being sandwiched between the heating roller 16A and the pressure roller 16B. As a result, the toner image is welded to the printing paper. Thereafter, the printing paper is discharged to the paper discharge tray 18.

  The control unit 71 performs overall control of the image forming apparatus 10. The control unit 71 is configured as a microcomputer whose main components are a CPU 71A, a ROM 71B, a RAM 71C, and the like. The control unit 71 may be configured with an electronic circuit such as an integrated circuit (ASIC, DSP). The control unit 71 is connected to each image forming unit 4, the secondary transfer device 20, the fixing device 16, the driving roller 6 </ b> A, and the like inside the image forming apparatus 10, and controls these components. In addition, the control unit 71 controls each element constituting the image forming unit 4, specifically, the charging device 12, the optical scanning device 13, the developing device 14, the primary transfer device 15, the cleaning device 21, and the charge removal device 22. It is connected. The ROM 71B stores a program for executing image forming processing. The CPU 71A executes a control program in the ROM 71B to control each element connected to the control unit 71 and print a color image on printing paper. The RAM 71C temporarily stores information and image data when the CPU 71A executes the control program.

  In this way, the image forming apparatus 10 transfers the color toner images by superimposing them onto the running intermediate transfer belt 5 by the plurality of image forming units 4 (4B, 4Y, 4C, 4M), thereby forming color toners. An image is formed on the surface of the intermediate transfer belt 5. Further, the image forming apparatus 10 forms a color image on the printing paper by transferring the formed color toner image from the intermediate transfer belt 5 to the printing paper by the secondary transfer device 20. A configuration in which the intermediate transfer belt 5 is used as a conveyance belt and a toner image is directly superimposed and transferred onto printing paper conveyed on the conveyance belt, or a roller-shaped intermediate transfer member is used instead of the intermediate transfer belt 5 The use of is also considered as another embodiment.

[Developing device 14]
Next, a schematic configuration of the developing device 14 will be described with reference to FIGS. 3 to 6. The developing device 14 is a developing device that performs development using a developer composed of two components of a toner and a carrier (an example of the developer of the present invention). 5 and 6 is the longitudinal central axis of the developing magnetic roller 49, and the line 62 is the lateral central axis of the developing magnetic roller 49.

  As shown in FIGS. 3 and 4, the developing device 14 is formed in a long shape in the front-rear direction 7. Therefore, the longitudinal direction of the developing device 14 coincides with the front-rear direction 7. The developing device 14 includes a casing 41 (an example of a developer container according to the present invention), a first screw feeder 47 (an example of a first transport body according to the present invention), a second screw feeder 48 (a second transport body according to the present invention). An example), a developing magnetic roller 49 (an example of the developer carrier of the present invention), a regulating blade 50 (see FIGS. 5 and 6), and the like. In FIG. 3, cross sections of the first screw feeder 47, the second screw feeder 48, and the developing magnetic roller 49 appear, but hatching indicating these cross sections is omitted for convenience. As shown in FIGS. 3, 5, and 6, the housing 41 includes a first storage chamber 43 (an example of the first storage chamber of the present invention) and a second storage chamber 44 ( An example of the second storage chamber of the present invention. The first storage chamber 43 is a cylindrical space having an opening on the side where the developing magnetic roller 49 is disposed, and stores the developer. The second storage chamber 44 is a cylindrical space and stores a developer. The first screw feeder 47 is arranged such that the center of the rotation axis coincides with the center of the cylindrical bottom surface of the first storage chamber 43, and conveys the developer in the first storage chamber 43 while stirring. The second screw feeder 48 is arranged so that the center of the rotation axis coincides with the center of the cylindrical bottom surface of the second storage chamber 44, and conveys the developer in the second storage chamber 44 while stirring.

  The developing magnetic roller 49, the first screw feeder 47, and the second screw feeder 48 are connected to a stepping motor via gears (not shown). As shown in FIGS. 5 and 6, the stepping motor supplies rotational force through a gear to move the developing magnetic roller 49, the first screw feeder 47, and the second screw feeder 48 in the first rotation direction 51. Rotate. As a result, the developer stored in the first storage chamber 43 and the second storage chamber 44 is agitated. 5 and 6, the cross sections of the first screw feeder 47, the second screw feeder 48, and the developing magnetic roller 49 appear, but for convenience, hatching indicating these cross sections is omitted and shown by a two-dot chain line. Represents.

  In the present embodiment, the transport amount per unit time (see the direction of arrow 32 in FIG. 3) in which the second screw feeder 48 transports the developer is the transport amount per unit time in which the first screw feeder 47 transports the developer. (See FIG. 3, arrow 31 direction) In general, the rotational speeds of the developing magnetic roller 49, the first screw feeder 47, and the second screw feeder 48 are determined by the gear ratio of the gears. Therefore, in this embodiment, the gear ratio is determined so that the rotational speed of the second screw feeder 48 is higher than the rotational speed of the first screw feeder 47. As a result, the transport amount by the second screw feeder 48 is larger than the transport amount by the first screw feeder 47, so that the amount of the developer staying in the first storage chamber 43 stays in the second storage chamber 44. More than the amount of developer. It should be noted that the distance between the spiral wings of the second screw feeder 48 may be made wider than the interval between the spiral wings of the first screw feeder 47, so that the developer transport amount may be different.

  As shown in FIG. 3, the first storage chamber 43 and the second storage chamber 44 extend in the front-rear direction 7 and are arranged vertically. The first storage chamber 43 is on the upper side, and the second storage chamber 44 is on the lower side. The first storage chamber 43 and the second storage chamber 44 are integrally formed with the casing 41 and are partitioned from each other via a partition wall 42 (an example of a partition wall of the present invention) extending in the front-rear direction 7. That is, the partition wall 42 is a lower wall that forms the bottom surface of the first storage chamber 43, and an upper wall that forms the upper surface of the second storage chamber 44. However, the first storage chamber 43 and the second storage chamber 44 are not completely partitioned. As shown in FIGS. 3 to 6, the partition wall 42 has a first communication portion 42 </ b> A (an example of the first communication portion of the present invention) and a second communication portion 42 </ b> B (the main communication portion) at positions separated in the front-rear direction 7. An example of the second communication portion of the invention is formed. In the present embodiment, the first communication portion 42 </ b> A is at the front end of the partition wall 42 in the front-rear direction 7. That is, the front end portion of the partition wall 42 is the first communication portion 42A. The second communication portion 42 </ b> B is at the rear end of the partition wall 42 in the front-rear direction 7. That is, the rear end of the partition wall 42 is the second communication portion 42B.

  As shown in FIG. 4, the developing device 14 is formed in a short shape in the left-right direction 9. Accordingly, the short side direction of the developing device 14 coincides with the left-right direction 9. The first communication portion 42A is formed with a first hole 45 (an example of the first hole of the present invention) that allows the first storage chamber 43 and the second storage chamber 44 to communicate with each other. In the second communication portion 42B, a second hole 46 (an example of the second hole of the present invention) that communicates the first storage chamber 43 and the second storage chamber 44 is formed. The first hole 45 is provided at an end portion on the right side which is one side in the left-right direction 9 (short direction). The second hole 46 is provided at the left end which is the other side in the left-right direction 9. In the developing device 14, the first accommodation chamber 43 and the second accommodation chamber 44 are communicated at two locations by the first hole 45 and the second hole 46.

  The first screw feeder 47 is provided with right-handed spiral wings around a rotation axis extending in the front-rear direction 7. The first screw feeder 47 is rotated in the first rotation direction 51 around the axis by the stepping motor to convey the developer in the first storage chamber 43 to the rear side while stirring. The second screw feeder 48 is provided with a left-handed spiral wing around a rotation axis extending in the front-rear direction 7. The second screw feeder 48 is rotated in the first rotation direction 51 around the axis by the stepping motor, thereby conveying the developer in the second storage chamber 44 to the front side while stirring. Thus, although the rotation direction of each of the first screw feeder 47 and the second screw feeder 48 is set to the same first rotation direction 51, the winding direction of the spiral wings is opposite, The developer is conveyed in the direction opposite to direction 7.

  As shown in FIGS. 5 and 6, the first screw feeder 47 is configured such that the wings move from below to above on the right side of the vertical plane (see the broken line 61) passing through the rotation axis of the first storage chamber 43. On the left side, the wing moves from top to bottom. Therefore, the first screw feeder 47 imparts a component to move upward to the developer on the right side (an example of the first side of the present invention) from the vertical surface, and lowers the developer on the left side from the vertical surface. Gives the component to move to. Similarly, in the second screw feeder 48, the wings move from below to above on the right side of the vertical plane (see broken line 61) passing through the rotation axis of the second storage chamber 44, and on the left side of the vertical plane (the first aspect of the present invention). In the example of 2 side, the wing moves from top to bottom. For this reason, the second screw feeder 48 applies a component force for moving upward to the developer located on the right side of the vertical surface, and applies a component force for moving the developer located on the left side of the vertical surface downward. Further, the component force in the vertical direction of the first screw feeder 47 and the second screw feeder 48 is stronger near the end than near the center of rotation. Therefore, if the first hole 45 having the same area is to be formed, a position and shape in which the region near the end of rotation is larger than the region near the center of rotation is more desirable.

  As described above, since the first storage chamber 43, the second storage chamber 44, the first hole 45, and the second hole 46 are formed in the housing 41, the first screw feeder 47 and When the second screw feeder 48 is rotated, the developer is conveyed while being stirred as follows. By rotating the second screw feeder 48, the developer in the second storage chamber 44 is formed with a first hole 45 that is downstream in the transport direction from the rear end where the second hole 46 is formed. It is conveyed while stirring to the front end. The conveyed developer collects at the front end in the second storage chamber 44. Further, when the second screw feeder 48 is rotated, the developer accumulated at the front end portion is pressed and pushed up toward the first hole 45. The pushed-up developer moves from the second storage chamber 44 to the first storage chamber 43 through the first hole 45. At this time, as described above, since the first hole 45 is located at the right end of the second storage chamber 44, the developer to which the upward force is applied by the second screw feeder 48 is directly above the first developer 45. It is smoothly conveyed to the hole 45. Since the developer moved upward from the first hole 45 is further moved upward by the first screw feeder 47 and moves upward, it does not interfere with the developer moved upward later. In other words, the first hole 45 is formed at a position where a component force that moves the developer upward is exerted, so that the movement of the developer from the second storage chamber 44 to the first storage chamber 43 is stable and continuous. become.

  By rotating the first screw feeder 47, the developer in the first storage chamber 43 is formed with a second hole 46 that is downstream in the transport direction from the front end where the first hole 45 is formed. It is conveyed with stirring to the rear end. The conveyed developer reaches the rear end in the first storage chamber 43. When the developer that has reached the rear end is moved to the position of the second hole 46, it falls from the second hole 46 due to gravity. At this time, as described above, since the second hole 46 is located at the left end of the first storage chamber 43, the developer to which the downward force is applied by the first screw feeder 47 is immediately below the second developer 46. It is smoothly conveyed to the hole 46. Since the developer moved downward from the second hole 46 is further moved downward by the second screw feeder 48, it does not interfere with the developer moved downward later. That is, the second hole 46 is formed at a position where a component force for moving the developer downward is applied, so that the developer can be stably and continuously moved from the first storage chamber 43 to the second storage chamber 44. become.

  In this embodiment, the opening width in the left-right direction 9 of the first hole 45 is set to half the length of the first storage chamber 43 and the second storage chamber 44 in the left-right direction 9. The opening width of the second hole 46 in the left-right direction 9 is set to half the length of the first storage chamber 43 and the second storage chamber 44 in the left-right direction 9. The opening width in the left-right direction 9 of the first hole 45 is less than or equal to half the length in the left-right direction 9 of the first storage chamber 43 and the second storage chamber 44, and the opening width in the left-right direction 9 of the second hole 46. However, it may be less than half the length of the first storage chamber 43 and the second storage chamber 44 in the left-right direction 9. As described above, an upward force is applied to the right side of the first storage chamber 43 and the second storage chamber 44 in the left-right direction 9, and a downward force is applied to the left side. Moreover, the first hole 45 is even formed at the right end, and the second hole 46 is formed at the left end. Therefore, if the opening width of the first hole 45 in the left-right direction 9 is less than half, the first hole 45 receives only the upward component force. If the opening width in the left-right direction 9 of the second hole 46 is less than half, the second hole 46 receives only a downward component force. Therefore, the developer moves between the first storage chamber 43 and the second storage chamber 44 in a stable and continuous manner.

  As described above, since the first hole 45 and the second hole 46 are formed between the first storage chamber 43 and the second storage chamber 44, the developer is used in the first storage chamber 43 and the second storage chamber. It is circulated and conveyed in the direction shown by arrows 31 to 34 in FIG. By this stirring, the toner of the developer in which the toner and the carrier are mixed has a charge.

[Developing magnetic roller 49]
As shown in FIGS. 3 to 6, the developing magnetic roller 49 is provided above the first storage chamber 43 and is disposed along the front-rear direction 7 of the developing device 14. The developing magnetic roller 49 is rotated in the first rotation direction 51 (counterclockwise rotation direction, see FIGS. 5 and 6) during development. A magnetic pole support (not shown) is arranged inside the developing magnetic roller 49. The magnetic pole support has a cylindrical shape that is long in the axial direction of the developing magnetic roller 49. A plurality of magnetic poles are provided on the surface of the magnetic pole support. These magnetic poles are constituted by, for example, permanent magnets. If one magnetic pole of the permanent magnet is directed outward and there is no influence of the magnetic force from the other magnetic pole, the magnetic force in that direction becomes a maximum value. As shown in FIGS. 5 and 6, the developing magnetic roller 49 has a plurality of magnetic poles, has a main pole 65 at a position facing the photoconductive drum 11, and the first rotation direction from the main pole 65. In order to 51, it has the conveyance pole 66, the separation pole 67 (an example of the 1st magnetic force generation part of this invention), the scooping pole 63 (an example of the 2nd magnetic force generation part of this invention), and the control pole 64. The main electrode 65 is provided at a position facing the photosensitive drum 11 and has a polarity of N. The regulation pole 64 is provided at a position facing the regulation blade 50, and the polarity is the S pole. The pumping pole 63 is a position facing the first storage chamber 43 and is provided in the direction of the first hole 45, and the polarity is the N pole. The transport pole 66 is provided downstream of the main pole 65 in the first rotation direction 51, and the polarity is the S pole. The separation pole 67 is provided downstream of the transport pole 66 in the first rotation direction 51, provided upstream of the pumping pole 63 in the first rotation direction 51, and has a polarity of N pole. Each magnetic pole direction is indicated by arrows 63A to 67A.

  The developing magnetic roller 49 magnetically attracts the developer stored in the first storage chamber 43 onto the circumferential surface of the magnetic roller by the magnetic force of the drawing upper pole 63. Since the magnetic pole direction (arrow 63A) of the drawing upper pole 63 faces the first hole 45, the conveying force of the developer moved from the second storage chamber 44 to the first storage chamber 43 is improved. As a result, the developer moves from the first storage chamber 43 to the second storage chamber 44 in a more stable and continuous manner. The adsorbed developer is magnetically held as a developer layer (magnetic brush layer) on the peripheral surface of the developing magnetic roller 49 and is conveyed toward the regulating blade 50 as the developing magnetic roller 49 rotates.

  The restricting blade 50 is formed on the upstream side of the drawing upper pole 63 in the first rotation direction 51 and above the first storage chamber 43. The regulating blade 50 regulates the layer thickness of the developer layer that is magnetically attached to the peripheral surface of the developing magnetic roller 49. The regulating blade 50 is a plate member made of a magnetic material that extends along the front-rear direction 7 of the developing magnetic roller 49, and is supported by a predetermined support member fixed at an appropriate position of the housing 41. Further, the regulation blade 50 has a regulation surface that forms a regulation gap of a predetermined size with the peripheral surface of the developing magnetic roller 49 (that is, the tip surface of the regulation blade 50).

  The regulating blade 50 formed from a magnetic material is magnetized by the regulating pole 64 of the developing magnetic roller 49. Thereby, a magnetic path is formed between the regulation surface of the regulation blade 50 and the regulation pole 64, that is, in the regulation gap. When the developer layer adhered on the peripheral surface of the developing magnetic roller 49 by the scooping pole 63 is conveyed into the regulation gap as the developing magnetic roller 49 rotates, the layer thickness of the developer layer is determined in the regulation gap. Be regulated. As a result, a uniform developer layer having a predetermined thickness is formed on the peripheral surface of the developing magnetic roller 49.

  The photosensitive drum 11 shown in FIG. 2 is arranged so as to extend in parallel with the position facing the developing magnetic roller 49 in the front-rear direction 7. The photosensitive drum 11 is rotated in the second rotation direction 53 (clockwise rotation direction, opposite to the first rotation direction 51) during development. The developer layer whose thickness is uniformed by the regulating blade 50 on the developing magnetic roller 49 is retained on the electrostatic latent image formed on the photosensitive drum 11 while being held by the largest magnetic force in the vicinity of the main pole 65. The toner moves and development is performed. Then, the developer layer in which the toner is consumed as a result of the toner moving to the photosensitive drum 11 is conveyed to the separation pole 67 while being adsorbed on the developing magnetic roller 49 by the magnetic force of the conveyance pole 66.

  The magnetic pole direction (arrow 67A) of the separation pole 67 and the magnetic pole direction (arrow 63A) of the scooping pole 63 are the outward directions, and the separation pole 67 and scooping pole 63 are arranged at positions appropriately separated. For this reason, a non-magnetic region 69 (zero gauss region) in which the magnetic force of the separation pole 67 and the magnetic force of the pumping pole 67 are combined to be magneticless can be provided between the separation pole 67 and the pumping pole 63. The non-magnetic region 69 on the developing magnetic roller 49 is a developer peeling position where the developer adsorbed on the developing magnetic roller 49 is peeled off. For this reason, the position on the surface of the developing magnetic roller 49 that is positioned vertically above the second hole 46 and faces the second hole is the developer peeling position (the non-magnetic region 69). Adjust as follows. As a result, when the developing layer on which the toner on the surface of the developing magnetic roller 49 has been consumed is conveyed to the developer peeling position (the non-magnetic region 69), the developing layer loses the attractive force due to the magnetic force and peels off from the developing magnetic roller 49. Return to the storage chamber 43. Since the developer peeled off at the developer peeling position (the non-magnetic region 69) falls by gravity, a part of the developer moves onto the second hole 46. Therefore, the developer easily moves from the first storage chamber 43 to the second storage chamber 44 by the downward component force of the first screw feeder 47 and the second screw feeder 48.

  As described above, in the present embodiment, the first hole 45 is formed near the right end in the left-right direction 9, and the second hole 46 is formed near the left end in the left-right direction 9. Since the polarity of the scooping pole 63 is directed toward the right end direction of the first storage chamber 43, the developer easily moves from the second storage chamber 44 to the first storage chamber 43 by magnetic force. On the other hand, since the non-magnetic region 69 (developer peeling position) is formed vertically above the left end direction of the first storage chamber 43, the developer is not affected by the magnetic force, and the developer is not affected by the magnetic force. It is easy to move from 43 to the second storage chamber 44. As described above, since the first hole 45 and the second hole 46 are formed at positions farthest in the left-right direction 9, the developer can be moved upward by a magnetic force.

  Further, the right side of the second storage chamber 44 and the right side of the first storage chamber 43 correspond to the regions where the upward component force is the strongest by the second screw feeder 48 and the first screw feeder 47, so that the developer is first generated by the component force. It is easy to move from the two storage chambers 44 to the first storage chamber 43. On the other hand, the left side of the first storage chamber 43 and the left side of the second storage chamber 44 are regions where the downward component force is the strongest by the first screw feeder 47 and the second screw feeder 48, and therefore development is performed by the component force. The agent easily moves from the first storage chamber 43 to the second storage chamber 44. Thus, since the first hole 45 and the second hole 46 are formed at positions farthest in the left-right direction 9, the developer can be moved by a component force.

  As described above, in the so-called vertical developing device in which the first storage chamber 43 and the second storage chamber 44 are formed in two upper and lower stages, the second storage chamber 44 and the first storage chamber 43 are continuously and stably developed. The agent can be moved. Therefore, the amount of the developer in the first storage chamber 43 can be made sufficient, and the developer can be spread uniformly in the first storage chamber 43.

[Modification of Embodiment]
In the description of the above-described embodiment, the case where the first hole 45 is formed near the right end portion in the left-right direction 9 and the second hole 46 is formed near the left end portion in the left-right direction 9 will be described. However, it is not limited to this. For example, the center line 54 of the partition wall 42 is set in the left-right direction 9 orthogonal to the front-rear direction 7 and parallel to the partition wall 42 (see FIG. 4). The first hole 45 is provided at a position close to the right side, which is one side of the center line 54. On the other hand, it is conceivable that the second hole 46 is provided at a position close to the left side, which is the other side of the center line 54. Since the component force by the first screw feeder 47 and the second screw feeder 48 is divided into a region facing upward and a region facing downward, by forming the first hole 45 and the second hole 46 corresponding to the divided regions, The developer can be moved smoothly. Further, by shifting the positions of the first hole 45 and the second hole 46 in the left-right direction 9, the magnetic pole direction (arrow 63 </ b> A) of the scooping pole 63 can be directed only to the first hole 45. Therefore, the upward magnetic force acts on the first hole 45, so that the developer can easily move from the second storage chamber 44 to the first storage chamber 43. Further, when the developer moves from the first hole 46 to the second storage chamber 44 from the second hole 46, the influence of magnetic force can be reduced. Further, as long as the first hole 45 and the second hole 46 are formed at positions separated from each other in the front-rear direction 7 of the partition wall 42, the first hole 45 and the second hole 46 may not be formed at the left and right ends.

  In the description of the above-described embodiment, the transport amount per unit time (see the direction of the arrow 32 in FIG. 3) in which the second screw feeder 48 transports the developer, and per unit time in which the first screw feeder 47 transports the developer. However, the present invention is not limited to this case. For example, it is conceivable to form the opening area of the first hole 45 wider than the opening area of the second hole 46 by making the conveyance amounts of the first screw feeder 47 and the second screw feeder 48 the same. Accordingly, the amount of developer moving from the first storage chamber 43 to the second storage chamber 44 can be made smaller than the amount of developer moving from the second storage chamber 44 to the first storage chamber 43. As a result, the developer tends to stay in the first storage chamber 43.

  In the description of the present embodiment, the developing device 14 that supplies toner from the developing magnetic roller 49 to the photosensitive drum 11 has been described. However, the present invention is not limited to this. Instead of the developing magnetic roller 49, the developing device 14 including a developing roller and a magnetic roller may be used. Further, the developing device 14 having the second storage chamber 44 immediately below the first storage chamber 43 has been described, but the present invention is not limited to this. As long as the second storage chamber 44 is formed below the first storage chamber 43, it may be obliquely below. Similarly, although the case where the developing magnetic roller 49 is provided directly above the first storage chamber 43 has been described, the present invention is not limited to this. The developing magnetic roller 49 only needs to be disposed in the vicinity of the first storage chamber 43. For example, the first housing chamber 43 is located on the left side of the developing magnetic roller 49 and the second housing chamber 44, and the intermediate portion in which the cross section of the developing device 14 is along the peripheral surface of the photosensitive drum 11 is recessed. But you can.

  In the description of the present embodiment, the case where the developer has two components has been described. However, the present invention is not limited to this case. The developer may be one component. Further, the component force of the first screw feeder 47 and the second screw feeder 48 is directed upward and downward, the left and right positions of the first hole 45 and the second hole 46, the left and right of the pumping pole 63 and the non-magnetic region 69 (developer peeling position). The position of can be reversed.

  Since the scope of the present disclosure is defined not by the detailed description preceding the description of the claims but by the description of the appended claims, the embodiments described herein are merely exemplary and non-limiting I want to be understood. Therefore, all the changes which do not deviate from a claim, or an equivalent are included in a claim.

10: image forming apparatus 4: image forming unit 11: photoconductor drum 14: developing device 41: housing 42: partition wall 42A: first communication unit 42B: second communication unit 43: first storage chamber 44: second storage chamber 45: 1st hole 46: 2nd hole 47: 1st screw feeder 48: 2nd screw feeder 49: Developing magnetic roller 51: 1st rotation direction 53: 2nd rotation direction 54: Center line 63: Floating pole 64: Restriction Pole 65: Main pole 66: Conveying pole 67: Separating pole 69: Non-magnetic region 31, 32: Developer conveying direction

Claims (10)

A developer container having a first storage chamber in which a developer is stored and a second storage chamber provided below the first storage chamber via a partition wall in which the developer is stored;
A first communication portion formed in the partition wall and having a first hole communicating between the first storage chamber and the second storage chamber;
A second communication portion formed at a position spaced apart from the first communication portion in the predetermined direction in the partition wall, and having a second hole communicating between the first storage chamber and the second storage chamber;
A first transport unit that is provided in the first storage chamber and transports the developer from the first hole toward the second hole;
A second transport unit that is provided in the second storage chamber and transports the developer from the second hole toward the first hole;
A developer carrier that is provided above the developer container and that adsorbs the developer contained in the first storage chamber to the surface by magnetic force;
A first magnetic force generator provided inside the developer carrier and having a magnetic pole for generating the magnetic force directed toward the first hole;
A developing device comprising: The developer container is formed in a long shape in one direction;
The first hole and the second hole are provided apart in the longitudinal direction of the developing container,
The first hole is provided at a position that is close to one side of the short direction perpendicular to the longitudinal direction and parallel to the partition;
The developing device according to claim 1, wherein the second hole is provided at a position close to either side in the short direction. The first hole is provided at an end portion on one side in the short-side direction,
The developing device according to claim 2, wherein the second hole is provided at an end portion on the other side in the lateral direction. The first transport unit and the second transport unit are provided with spiral wings around a rotation axis extending in the longitudinal direction, and are determined in advance from a vertical plane passing through the rotation shaft inside the developer container. The component on the first side is applied with a component that moves upward,
The developing device according to claim 1, wherein the first hole is provided on the first side of the partition wall. The first transport unit and the second transport unit impart a component force to move downward to the developer on the second side opposite to the first side in the vertical plane,
The developing device according to claim 4, wherein the second hole is provided on the second side of the partition wall.   The combined magnetic force with the first magnetic force generator is provided on the surface of the developer carrier that is provided inside the developer carrier and is located vertically above the second hole and faces the second hole. The developing device according to claim 1, further comprising a second magnetic force generator that forms a non-magnetic region.   The conveyance amount per unit time that the second conveyance unit conveys the developer is larger than the conveyance amount per unit time that the first conveyance unit conveys the developer. Development device.   The opening width in the short direction of the first hole and the opening width in the short direction of the second hole are less than or equal to half of the width in the short direction of the first storage chamber and the second storage chamber. The developing device according to claim 1.   The developing device according to claim 1, wherein an opening area of the first hole is larger than an opening area of the second hole.   An image forming apparatus comprising the developing device according to claim 1.

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