JP5444979B2 - Developing device and image forming apparatus - Google Patents

Description

  The present invention relates to a developing device and an image forming apparatus, and more particularly to a stirring mechanism for a two-component developer.

  In an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a printing machine, an electrostatic latent image formed on a photosensitive member as a latent image carrier is subjected to visible image processing by a developing device, and the visible image is converted into a sheet. A recording output can be obtained by transferring to the above.

  As a developer used for development, there is a two-component developer obtained by mixing a toner and a carrier in addition to a one-component developer containing only a magnetic or non-magnetic toner.

  The two-component developer is composed of a toner and a carrier that carries the toner, and the toner can be electrostatically attracted to the electrostatic latent image on the photosensitive member by charging the toner by a frictional charging effect that occurs during stirring and mixing. It is said.

  In the development using a two-component developer, in particular, in the development used, a member for supplying the developer to the developer carrier and the developer after development from the developer carrier in addition to the developer carrier. There is a configuration in which it is collected and circulated again toward the supply member.

  In such a configuration, it is known to use a conveying member using a screw auger or the like as a supply member and a collecting member, and the developer is stirred and mixed in the process of being conveyed in the axial direction by the rotation of the conveying screw. Then, the replenished toner and developer are agitated.

  The above-described screw augers are arranged in the supply conveyance path and the collection conveyance path, respectively, and the conveyance paths can perform the delivery of the developer by a communication portion provided in a member that partitions these conveyance paths. Yes.

  By the way, the developer that has passed through the development region is reduced in toner concentration due to toner consumption by the development process. In particular, when an image with a high image area ratio is developed, the amount of toner consumption increases, and when the toner is transported in the axial direction by the rotation of the transport screw, the toner density decreases on the downstream side in the transport direction. Become prominent.

  As described above, in the configuration in which the supply conveyance space and the collection conveyance space are provided, the developer that has passed through the development region is not returned to the supply conveyance space, but is moved to the collection conveyance space, and is stirred and mixed again. In addition, since it circulates in the supply conveyance space, it is possible to reduce the possibility that the toner density on the downstream side in the conveyance direction in the supply conveyance space decreases.

  However, when the developer after development is not returned to the supply conveyance space, the amount of developer in the supply conveyance space decreases. In addition, when the cross-sectional shape of the supply conveyance space is uniform in the conveyance direction, the developer surface height is separated toward the downstream side in the conveyance direction where the amount of developer decreases, and the developing sleeve can be uneven. The amount of developer supplied to the developing sleeve is also shifted in the axial direction of the developing sleeve.

  On the upstream side of the supply conveyance path where the developer surface is high, the amount of developer supplied to the developing sleeve is stable and the image density is constant, while on the downstream side of the supply conveyance path where the developer surface is low, The amount of developer supplied to the developing sleeve becomes unstable, density unevenness occurs in the image, and an image defect occurs.

  In order to prevent this, it is necessary to circulate a sufficient amount of developer so that depletion does not occur downstream.

  Therefore, for such a developer circulation structure, as a configuration for preventing a decrease in the developer amount on the downstream side in the transport direction, the developer transport capacity in the developing sleeve is arranged in the supply transport space. There is a configuration in which the developer conveying capability of the conveying screw is increased (for example, Patent Document 1).

  On the other hand, downsizing of the apparatus has been demanded in recent years, and the case of the developing apparatus is not special. In view of this, a configuration has been proposed in which the conveying screws for conveyance described above are arranged in the vertical direction instead of in the horizontal direction (for example, Patent Document 2). Such a configuration is particularly highly demanded in tandem color copiers and color printers in which a plurality of developing devices are juxtaposed.

  In the configuration where the conveying screw is arranged with the conveying space in the vertical direction, the developer can be circulated by communicating with each other, but the movement from the upper side to the lower side in the circulation process uses gravity. Although it is easy to do so, the movement from the lower side to the upper side is against gravity, making smooth movement difficult.

  As a method of moving from the lower side to the upper side, there is a method in which the developer deposited on the downstream side in the transport direction is raised and overflowed in the communication portion (for example, Patent Document 1).

  However, this method causes an increase in stress on the developer due to the aggregation of the developer deposited on the downstream side in the transport direction. Such an increase in stress on the developer may deteriorate the life of the developer by accelerating the peeling of the carrier film, the toner component adhering to the carrier, and the detachment or embedding of the toner external additive.

  Moreover, when the developing sleeve has a large diameter or a plurality of developing sleeves are arranged, the upper and lower transport paths are separated from each other, so that it is difficult to sufficiently transport the developer to the supply transport path. If sufficient developer cannot be supplied in this way, as described above, the developer is depleted downstream of the supply conveyance path, resulting in an image problem.

  Therefore, a configuration has been proposed in which a member that conveys the developer from the lower side to the upper side is provided instead of using the decrease in the overflow of the developer (for example, Patent Document 2).

  In Patent Document 2, a developer conveying means is constituted by a rotating sleeve having a built-in fixed magnetic pole connected to a fixed magnetic pole in a developing sleeve, in addition to a conveying screw, and the developer after development is in a lower conveying space. A configuration is disclosed in which the developer is conveyed while being carried in the same manner as the developing sleeve from the first to the upper conveying space.

  Apart from this, there is a configuration in which a vertical screw capable of conveying the developer from the lower side to the upper side is provided separately from the conveying screw at a position where the upper and lower conveying spaces communicate with each other (for example, Patent Document 3).

  In the configuration disclosed in Patent Document 2, since the developer conveying means is provided coaxially with the developing sleeve, a length longer than the axial length of the developing sleeve is required, and the developing device installation space is required. May increase in size.

  In the configuration disclosed in Patent Document 3, a conveying capability equivalent to that of the conveying screw is required for the vertical screw positioned separately from the conveying screw. For this reason, in order to satisfy the capability in a range shorter than the axial length of the conveying screw, the diameter of the screw must be increased, and the developing device may be enlarged as in the configuration disclosed in Patent Document 2. is there. Moreover, when the screw diameter is not increased, the conveyance amount is ensured depending on the number of rotations. However, when the screw rotates at a high speed, a new problem arises that stress on the developer increases.

  The object of the present invention is to suppress the increase in stress on the developer without increasing the size of the conventional developing device, particularly when the configuration in which the conveying screws are arranged in the vertical direction is targeted. In other words, an object of the present invention is to provide a developing device and an image forming apparatus having a configuration capable of ensuring a circulation amount.

In order to achieve this object, the present invention has the following configuration.
(1) A developing device for processing a visible image of an electrostatic latent image formed on a latent image carrier with a developer composed of a toner and a carrier,
First and second transport spaces provided adjacent to each other in the direction of gravity and in which a developer stirring and transporting member is disposed;
A communication portion provided in a partition portion that partitions the first and second transport spaces and serving as a developer delivery portion;
The communication unit, the gravity direction lower side has an inverted conical shape tapering, inside of its said separately from the developer stirring and conveying member, the transfer conveyer to convey the developer to the developer stirring member The transfer conveying member has a transfer conveying capability corresponding to an amount capable of conveying the developer per unit time toward the developer agitating / conveying member at the communicating portion. A developing device characterized in that the developing device has a stirring and conveying capability higher than an amount capable of conveying a developer per unit time in a conveying direction by a member.
(2) A developing device for processing a visible image of an electrostatic latent image formed on a latent image carrier with a developer composed of toner and carrier,
First and second transport spaces provided adjacent to each other in the direction of gravity and in which a developer stirring and transporting member is disposed;
A communication portion provided in a partition portion that partitions the first and second transport spaces and serving as a developer delivery portion;
In addition to the developer agitating and conveying member, a transfer conveying member that conveys the developer toward the developer agitating member is provided inside the communication portion, and the conveying member for transferring pushes the developer. A rotating member provided with a linear part constituting a developer passage part on at least a part of the moving surface, and in the communicating part, the developer can be transported per unit time toward the developer stirring and transporting member. The developing apparatus according to claim 1, wherein the transporting capacity for transfer is higher than the stirring and transporting capacity corresponding to an amount capable of transporting the developer per unit time in the transporting direction by the developer stirring and transporting member .
(3) A developing device for processing a visible image of an electrostatic latent image formed on a latent image carrier with a developer composed of a toner and a carrier,
First and second transport spaces provided adjacent to each other in the direction of gravity and in which a developer stirring and transporting member is disposed;
A communication portion provided in a partition portion that partitions the first and second transport spaces and serving as a developer delivery portion;
The communicating part is provided with an ascending air supply part, and a transfer conveying member for conveying the developer toward the developer agitating member is provided in the communication part, in addition to the developer agitating and conveying member. The transfer conveying member has a transfer conveying capability corresponding to an amount capable of conveying the developer per unit time toward the developer agitating / conveying member at the communicating portion. A developing device characterized in that the developing device has a stirring and conveying capacity higher than an amount capable of conveying the developer per unit time in the direction .
(4) The transfer speed of the developer by the transfer conveying member provided in the communication portion can be changed according to the circulation amount of the developer (1) to ( 3) An apparatus according to any one of.
(5) The communication portion is provided with a transfer auxiliary member that can be interlocked with the transfer conveyance member, and the transfer auxiliary member is formed of a spiral or propeller-shaped rotating member, and pushes up the developer. The developing device according to any one of (1) to (4) , wherein the developing device can be pushed and moved .
(6) A toner replenishing portion is provided in the vicinity of the communicating portion in the conveying space located on the lower side in the gravitational direction on the upstream side in the conveying direction of the developer moving toward the communicating portion. 1) to a developing device according to any one of (5).
(7) The developing device according to any one of (1) to (6) , wherein the communication unit is provided with an ascending air supply unit.
(8) An image forming apparatus using the developing device according to any one of (1) to (7) .

  According to the present invention, since the transfer conveying member is provided in the communicating portion that communicates the conveying spaces adjacent in the gravity direction in the developing device, the developer of the developing device against gravity is provided in the existing configuration of the developing device. Members that cause movement can be included. Thereby, it is possible to prevent the developing device from becoming large. In addition, the developer agitating / conveying member per unit time toward the developer agitating member with respect to the agitating / conveying capacity corresponding to the amount of developer that can be conveyed per unit time in the conveying direction of the developer agitating / conveying member. By providing a transfer conveying member having a high transfer conveying capability corresponding to the amount capable of conveying the developer, the transfer conveying capability is set to be equal to or higher than the developer agitating and conveying member conveying capability, It is possible to prevent the developer transport amount toward the developer agitating / conveying member from being insufficient, and in particular, to prevent the transport amount that is likely to occur when the developer moves against gravity from being insufficient. it can.

1 is a schematic diagram illustrating a configuration of a developing device targeted by the present invention. FIG. 2 is a schematic diagram for explaining a developer conveyance (dispersion) state in the developing device shown in FIG. 1. It is a figure for demonstrating the characteristic part of the image development apparatus by the Example of this invention. It is a figure for demonstrating the characterizing part of the developing device by another Example of this invention. It is a figure for demonstrating the characterizing part of the developing storehouse by the other Example of this invention. It is a figure for demonstrating the characterizing part of the apparatus by other Example of this invention. 1 is a schematic diagram for explaining a configuration of an image forming apparatus using a developing device according to the present invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  Prior to the description of the present invention, the configuration of the developing device targeted by the present invention will be described with reference to FIG.

  In FIG. 1, the developing device (indicated by reference numeral 30 indicating a casing for convenience) has a supply conveyance space 30 </ b> A serving as a developer supply space for the developing sleeve 31 in the gravity direction (vertical direction). A collection side conveyance space 30B for collecting the developer after development is located on the lower side adjacent to the side conveyance space 30A.

  Conveying screws 32 and 33 parallel to the axial direction of the developing sleeve 31 are provided in the conveying spaces 30A and 30B, and the conveying screws 32 and 33 can convey the developer in opposite directions. Has been.

  In the developing device 30, the developer stirred and conveyed by the conveying screw 32 is supplied from the supply-side conveying space 30 </ b> A to the developing sleeve 31, and the developer carried on the developing sleeve 31 has a layer thickness defined by the doctor blade 34. In contact with the photoreceptor 1.

  The developer remaining in the developing sleeve 31 after the development moves to the collection-side transport space 30B without returning to the supply-side transport space 30A by the action of the repulsive magnetic pole built in the developing sleeve 31, and is stirred and transported by the transport screw 33. Is done.

  FIG. 1B shows a cross section of the main part of each transport space in the developing device. In FIG. 1B, the supply-side transport space 30A and the collection-side transport space 30B are partitioned by a partition member 35. The developer is circulated through communication portions 36 and 36 ′ in which the lacking portions at both ends of the member 35 are used.

  In this configuration, the movement of the developer will be described again. The developer is transported from the front side to the back side in FIG. 1A in the supply-side transport space 30A, and the developer is transported in the transport process. Is supplied to the developing roller 31. It flows down toward the collection-side transport space 30E 'via a communication portion located on the back side of the sheet of FIG.

  The developer remaining on the developing roller 31 moves to the collection-side transport space 30E ′ side by a repulsive magnetic field from a repulsive magnetic pole built in the roller 31, and is transported from the back side to the near side by the transport screw 33 in FIG. Is moved to the supply-side transport space 30E by being accumulated and raised at the communication portion located on the front side of the sheet.

  In this embodiment, toner supply is performed when the toner concentration is insufficient. As a configuration for this, the developer will be described with reference to FIG. 1. In the collection side space 30B, the developer is supplied from the collection side conveyance space 30B to the supply side. A replenishment portion (indicated as (toner replenishment portion) in FIG. 1) is provided on the upstream side in the developer movement direction with respect to the communication portion 36 that moves toward the conveyance space 30A.

  FIG. 2 is a schematic diagram showing a distribution state of the developer in the developing device 30 having the configuration shown in FIG.

  In FIG. 2, the developed developer increases in bulk from the upstream side toward the downstream side in the transport direction by the transport screw 33 provided in the collection-side transport space 30B. The developer stirred and conveyed by the conveying screw 33 reaches the end of the conveying screw 33 and accumulates by being pushed toward the communicating portion 36 side, thereby further increasing the bulk.

  On the other hand, in the supply side conveyance space 30 </ b> A, the developer in the developer is consumed by the developing roller 31 during the conveyance process by the conveyance screw 32, so that the developer decreases and gradually decreases as the end of the conveyance screw 32 is reached. To do. Thereby, the bulk of the developer is lowered.

  The developer that has reached the end of the conveyance screw 32 in the supply conveyance space 30A falls again into the collection-side conveyance space 30B via the communication portion 36 '.

  In such a circulation of the developer, it is necessary that the developer is circulated stably. However, when the fluidity deteriorates due to the deterioration of the developer or the like, the communication unit 36 lifts and moves the developer. Cannot be transported satisfactorily, and a sufficient amount of developer cannot be transported to the supply-side transport space 30A. When such a phenomenon occurs, the developer screw is depleted on the downstream side in the transport direction by the transport screw 32 positioned in the supply-side transport space 30A, and an abnormal image such as insufficient density is generated. Further, if the balance of the developer transported in the supply-side transport space 30A, that is, the dispersed state shown in FIG. 2 collapses at the downstream end portion in the transport direction, the development amount differs from the transport amount by the transport screw 32. As a result, the developer may leak from the communication portion 36 ′, and the amount of developer supplied on the downstream side in the transport direction is reduced, and due to this lack of bulk, the developer cannot be supplied to the developing sleeve 31. There is a risk of becoming.

  For the present invention and a developing device having such a configuration, a configuration that is a feature described in FIG.

  FIG. 3 is a diagram for explaining one of the features of the developing device according to the present embodiment.

  The developing device shown in FIG. 3 (denoted by reference numeral 40 for convenience) differs from the configuration shown in FIG. 1 in that the developing sleeve (denoted by reference numerals 31 and 31 ′ for convenience) is moved along the moving direction of the photoreceptor 1. They are arranged side by side. With such a configuration, it is possible to reduce the axial length of the members having the axial direction including the photosensitive member 1 to save space, and to improve the development efficiency in forming a high-speed image.

  As in FIG. 1, each conveyance space in the developing device 40 is provided with a supply conveyance space 40 </ b> A on the upper side in the gravity direction and a supply-side conveyance space 40 </ b> B on the lower side in the gravity direction. Is arranged.

  The developer flows to the developing sleeves 31 and 31 ′ in such a manner that the developer supplied from the supply-side transport space 30 </ b> A moves to the developing sleeve 31, and the developer that has passed through the developing region in the developing three portion 31 is disposed in the space 30 </ b> B. To the developing sleeve 31 '. Since the developer is reused in the developing sleeve 31 ', it is possible to continuously obtain a stable image corresponding to the image formation which is improved in development efficiency and speeded up. In FIG. 3, the state of movement to the developer is shown by an alternate long and short dash arrow.

  FIGS. 3B and 3C are views showing details of the communication portion 36 that moves in a state in which the developer is lifted out of the communication portions shown in FIG. 1.

  In the communication portion 36, a transfer conveying member 37 that moves the developer upward is provided separately from the conveying screws 32 and 33.

  The transfer conveying member 37 is composed of a paddle member supported by a rotating shaft 37A having an axial direction perpendicular to the axial direction of the conveying screws 32 and 33 (parallel to the developer conveying direction).

  As shown in FIG. 3C, the transfer conveyance member has a paddle member disposed along the circumferential direction at a phase of 90 degrees, and in the direction indicated by the arrow in FIG. It rotates in a direction (direction indicated by a white arrow) in which the developer swelled at the communication portion 36 can be pushed and moved toward the inside of the space 30A. Further, the configuration of the transfer conveyance member 37 in the axial direction is such that each paddle does not interfere with the rotation shafts of the conveyance screws 32 and 33, and the supply-side conveyance space 30A and the collection-side conveyance space 30B are excluded except for those portions. It is configured to occupy the space.

  The transfer conveying member 37 is a member that can be rotated and controlled independently of the conveying screw by a driving source (not shown), and the number of rotations is controlled according to the flow rate of the developer. As the rotation control, when the transport amount is large with reference to the transport amount of the developer, the rotation speed is increased so as not to cause insufficient supply of the developer to the supply-side transport space 30A.

  The transfer conveying member 37 has a stirring and conveying capacity corresponding to an amount capable of conveying the developer per unit time when the conveying screws 32 and 33 are agitated and conveyed in the horizontal direction. It is used as a member having a high transfer carrying capacity corresponding to the amount of developer that can be carried. That is, as described above, when the transfer conveying member 37 pushes the developer toward the conveying screw 32, a space is provided between the paddles from which the developer has been pushed out. For this reason, the developer that has flowed into the communication portion 36 from the collection side space 30 </ b> B is accumulated in the space described above, and the developer accumulated in the space is pushed out toward the conveying screw 32.

  As a result, compared to the case where the developer overflows from the communication portion 36 to the supply side space 30 </ b> A and reaches the conveyance screw 32, the developer collected together between the paddles is forced out toward the conveyance screw 32. The amount of conveyance reaching the conveyance screw 32 is increased in the case where the conveyance is carried out. In particular, such a difference in transport amount, that is, a difference in transport capability, is effective in preventing the developer from being insufficiently supplied when the developer is transported against gravity.

  Thus, by making the transfer conveying capacity higher than the agitating and conveying capacity, the developer stirred and conveyed in the collection-side conveying space 30B is lifted and transferred against gravity without stagnation in the communication part 36. Insufficient developer in the side conveyance space 30A is prevented in advance.

  In the embodiment having the above-described configuration, when the developer transported by the transport screw 33 reaches the communication portion 36 on the downstream side in the transport direction in the collection-side transport space 30B, it accumulates and rises to cause the supply-side transport space 30A. Overflowing.

  The developer overflowing in the supply side conveyance space 30 </ b> A is pushed and moved toward the supply side conveyance space by the transfer conveyance member 37, in other words, transferred in the conveyance direction by the conveyance screw 32.

  In addition, since the transfer conveying member 37 moves in a direction different from the moving direction of the developer conveyed by the conveying screw, the developer can be sheared and stirred. As a result, the developer moving in the communicating portion 36 has a reduced bulk density when agglomerated by stirring, and is improved in fluidity to prevent supply shortage due to deterioration of fluidity, and there is no clogging phenomenon due to aggregation. Smooth transfer is performed.

  On the other hand, since the transfer conveying member 37 can change the conveying capability according to the flow rate of the developer by rotation control, for example, even when the rotation number on the conveying screw side is changed due to a change in the printing speed, etc. It is possible to prevent the developer distribution state from being different from the initial state by changing the conveyance capability in accordance with the change.

  According to the present embodiment, since the transfer conveying member 37 is provided inside the communicating portion which is an existing component of the developing device, the structure is increased in size unlike the case where the configuration for ascending conveyance is provided outside the developing device. It will not become. Moreover, even when the developer is transported against gravity, the transporting capacity of the transporting member 37 is set so that the amount of developer transported is larger than the amount of developer transported by stirring. By increasing the conveyance capability of the conveyance screw 33 on the conveyance space 30B side, the developer necessary for the supply-side conveyance space 30A can be transferred without causing the communication portion 36 to stagnate the developer.

  Next, embodiments according to the third to fifth aspects of the present invention will be described.

  FIG. 4 is a schematic diagram for the communication portion 36 shown in FIG. 3 in order to explain the characteristic portion of the present embodiment.

  In the figure, the communication portion 36 ′ is formed in an inverted conical shape having a tapered lower side in the direction of gravity.

  Inside the communication portion 36 ′ having such a shape, a transfer conveying member 37 ′ having a shape following the inner surface shape of the communication portion 36 ′ is provided. The transfer conveying member 37 ′ shown in FIG. 4 has the same configuration and function as the paddle shape on the lower side in the direction of gravity is different from that shown in FIG. 3.

  On the other hand, a transfer auxiliary member 38 is integrally provided on the rotating shaft 37A of the transfer stirring member 37 'so as to be interlocked with the transfer conveying member 37'.

  The transfer auxiliary member 38 has a spiral shape or a propeller shape, and has a function of transferring the developer while rotating. In this embodiment, the spiral direction and propeller blade shape capable of generating a conveying force capable of pushing up the developer during rotation are selected.

  In such a configuration, in addition to the function of the transfer conveyance member 37 ′ described with reference to FIG. 3, the developer transfer capability can be further enhanced.

  In the present embodiment, the following operation is obtained.

  When the plurality of developing sleeves are provided as in the configuration shown in FIG. 3A, the distance between the shafts of the sleeves may increase due to an increase in the diameter of the developing sleeve. The conveyance path length of the communication part 36 between the collection side conveyance space 30B becomes long. For this reason, in this embodiment, it is possible to prevent the conveyance path length, in particular, the conveyance capability when the developer moves upward, in other words, the circulation force, from being lowered.

  Further, since the shape on the lower side in the gravity direction in the communication portion 36 ′ is an inverted conical shape, the gradient of the inner surface of the communication portion and the centrifugal force generated when the transfer conveying member 37 rotates as shown by the arrows in FIG. In combination, the developer can be moved up. Thus, the developer can be moved up and down without causing aggregation of the developer, in other words, without causing stress.

  Next, another feature regarding the configuration shown in FIG. 4 will be described.

  In FIG. 4, the transfer conveyance member 37 is provided with a plurality of linear portions 37 </ b> B ′ constituting a developer passage portion on a part of the surface for pushing the developer, that is, one of the paddles. A plurality of linear portions 37B 'are provided at predetermined intervals in the paddle portion, and a gap between the linear portions serves as a developer passage portion.

  By using such a configuration, a part of the developer can pass through the developer passage portion when the transfer conveyance member 37 ′ is rotating, so that an effect of reducing stress on the developer is enhanced.

  Moreover, the developer moved by the linear portion and the developer passing through the developer passing portion have different moving speeds during stirring, and the stirrability is improved by the friction due to the difference in speed and the frictional charging action. Will be enhanced.

  Next, an embodiment of the invention described in claim 7 will be described.

  FIG. 6 is a diagram showing details of the communication part 36 that is a characteristic part of the present embodiment.

  In the figure, the communication part 36 is provided with an air supply part 39 connected to an air supply member (not shown) as an ascending air supply part on the lower side in the direction of gravity in the communication part.

  The air supply unit 39 is provided with an opening at a communication position with the supply-side conveyance space 30B, and a porous member 40 is attached to the opening. As the porous member 40, a filter member having a mesh size that allows passage of air while preventing passage of carriers is used.

  In this embodiment, when air is supplied from an air supply source (not shown) toward the communicating portion 36, the air is taken into the developer in the communicating portion 36, and the developer is diffused. Further, the aggregation of the developer can be prevented and the fluidity can be improved.

  In addition, since the opportunity for contact between the developers increases due to the diffusion of the developer, the stirring property and the triboelectric charging property are improved. Note that the air supply direction, that is, the air ejection angle at the air supply unit 39 is set to an angle at which air is not sent directly to the supply-side transport space 30B, thereby suppressing the backflow of the developer and improving the fluidity. This is desirable. Further, the air supply amount can be adjusted in accordance with the amount of the developer in the same manner as the transfer conveyance member 37.

  Note that the air supply from the air supply unit 39 is mainly performed by the diffusion of the developer as described above. However, since the developer can be raised while diffusing depending on the directivity angle of the air supply unit, the supply of the rising airflow is performed. It is named as a department.

  Next, an image forming apparatus using the developing device described in the above embodiment will be described.

  In FIG. 7, when a document bundle is placed on the document table 102 of the ADF 101 with the image surface facing upward, and a start key on an operation unit (not shown) is pressed, the lowest document is fed to the feed roller 103 and the feed roller 103. It is fed to a predetermined position on the contact glass 105 by the feeding belt 104.

  After the image information is read by the image reading unit 106, the document on the contact glass 105 is discharged onto the paper discharge tray 108 by the feeding belt 104 and the discharge roller 107. When the document detection sensor 109 detects that the next document exists on the document table 102, the document is fed onto the contact glass 105 as described above.

  The image reading unit 106 performs line scanning on the image information of the original in the sub-scanning direction while irradiating the original on the contact glass 105 with the two lamps 128, and uses the reflected light as image data as the first mirror 129 and the second mirror. 130, the light is reflected in a predetermined direction by the third mirror 131, and sent to the CCD 133 via the lens unit 132 for reducing and forming an image.

  The image data read by the image reading unit 106 is sent to a writing unit 118 having a laser light emitting device 134, an fθ lens 135, a reflecting mirror 136, and the like via an image processing unit (not shown). An electrostatic latent image corresponding to the original image is formed on the top.

  Inside the main body 100, a photosensitive drum 1, a developing device having a casing 10, a fixing unit 121, a paper discharge unit 122, first to third paper supply devices 110, 111, 112, a vertical conveyance unit 116, and the like are arranged. Has been. The photosensitive drum 1 is uniformly charged by a charger (not shown) and then exposed to light information from the writing unit 118 to form an electrostatic latent image. The electrostatic latent image is developed by a developing device and is toner. An image is formed.

  A conveyor belt 120 is disposed below the photosensitive drum 1. The conveyance belt 120 also serves as conveyance means and transfer means for transfer paper, which is a recording medium. A transfer bias is applied from a power supply (not shown), and the transfer paper from the vertical conveyance unit 116 is conveyed at a constant speed with the photosensitive drum 1. While the toner image on the photosensitive drum 1 is transferred to the transfer paper.

  The toner image transferred to the transfer paper is fixed on the transfer paper in the fixing unit, and the transfer paper on which the image is fixed is discharged onto the paper discharge tray 123 via the paper discharge unit 122. The photosensitive drum 1 is cleaned by a cleaning unit (not shown) after the toner image is transferred, and is prepared for the next image formation.

  The paper discharge unit 122 includes a reversing unit 125 that feeds the transfer paper from the middle thereof by a pair of transport rollers 124, an image forming side transport path 126 that transports the transfer paper reversed by the reversing unit 125 to the vertical transport unit 116 side, and a reversal. A double-sided conveyance path having a paper discharge conveyance path 127 and the like for returning the transferred transfer paper to the paper discharge unit 122 again is provided. With this double-sided conveyance path, images can be formed on both sides of the transfer paper, or discharged onto the paper discharge tray 123 with the image-formed side down.

  When selected, the first to third paper feeding devices 110, 111, and 112 feed transfer sheets stacked on the first tray 113, the second tray 114, and the third tray 115, respectively.

  The fed transfer paper is conveyed to a position where it comes into contact with the photosensitive drum 17 by the vertical conveyance unit 116.

  In this image forming apparatus, image data from the outside is input to the writing unit 118 instead of the image data from the image processing means during the printer function, and an image is formed on the transfer paper by the image forming means.

During the facsimile function, the image data from the image reading unit 106 is transmitted to the other party by a facsimile transmission / reception unit (not shown), and the image data from the other party is received by the facsimile transmission / reception unit. As a result of the input, the image forming means operates to form an image on the transfer paper.

  In the above-described configuration, an example in which a multifunction peripheral is used as the image forming apparatus has been described. However, the image forming apparatus to which the present invention can be applied is not limited thereto, and other image forming apparatuses such as a copying apparatus, a printer, a facsimile machine, and a plotter. In addition, the present invention is applicable.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 40 Developing apparatus 40A Supply side conveyance space 40B Collection side conveyance space 32, 33 Conveyance screw 35 Partition member 36, 36 'Communication part 37, 37' Transfer conveyance member 37A Rotating shaft 37B Developer passage part 38 Transfer assist Member 39 Air supply part

Japanese Patent No. 3104722 Japanese Patent Laid-Open No. 10-142942 JP 2008-304846 A

Claims (8)

A developing device that processes a visible image of an electrostatic latent image formed on a latent image carrier with a developer composed of toner and a carrier,
First and second transport spaces provided adjacent to each other in the direction of gravity and in which a developer stirring and transporting member is disposed;
A communication portion provided in a partition portion that partitions the first and second transport spaces and serving as a developer delivery portion;
The communication unit, the gravity direction lower side has an inverted conical shape tapering, inside of its said separately from the developer stirring and conveying member, the transfer conveyer to convey the developer to the developer stirring member The transfer conveying member has a transfer conveying capability corresponding to an amount capable of conveying the developer per unit time toward the developer agitating / conveying member at the communicating portion. A developing device characterized in that the developing device has a stirring and conveying capability higher than an amount capable of conveying a developer per unit time in a conveying direction by a member. A developing device that processes a visible image of an electrostatic latent image formed on a latent image carrier with a developer composed of toner and a carrier,
First and second transport spaces provided adjacent to each other in the direction of gravity and in which a developer stirring and transporting member is disposed;
A communication portion provided in a partition portion that partitions the first and second transport spaces and serving as a developer delivery portion;
In addition to the developer agitating and conveying member, a transfer conveying member that conveys the developer toward the developer agitating member is provided inside the communication portion, and the conveying member for transferring pushes the developer. A rotating member provided with a linear part constituting a developer passage part on at least a part of the moving surface, and in the communicating part, the developer can be transported per unit time toward the developer stirring and transporting member. The developing apparatus according to claim 1, wherein the transporting capacity for transfer is higher than the stirring and transporting capacity corresponding to an amount capable of transporting the developer per unit time in the transporting direction by the developer stirring and transporting member . A developing device that processes a visible image of an electrostatic latent image formed on a latent image carrier with a developer composed of toner and a carrier,
First and second transport spaces provided adjacent to each other in the direction of gravity and in which a developer stirring and transporting member is disposed;
A communication portion provided in a partition portion that partitions the first and second transport spaces and serving as a developer delivery portion;
The communicating part is provided with an ascending air supply part, and a transfer conveying member for conveying the developer toward the developer agitating member is provided in the communication part, in addition to the developer agitating and conveying member. The transfer conveying member has a transfer conveying capability corresponding to an amount capable of conveying the developer per unit time toward the developer agitating / conveying member at the communicating portion. A developing device characterized in that the developing device has a stirring and conveying capacity higher than an amount capable of conveying the developer per unit time in the direction . Transport speed of the developer by the transfer conveying member provided in the communicating portion of claim 1 to 3, characterized in that the circulation amount of the developer is capable of being changed in correspondence The developing device according to any one of the above. The communication portion is provided with a transfer auxiliary member that can be interlocked with the transfer conveyance member, and the transfer auxiliary member is constituted by a spiral or propeller-shaped rotating member, and pushes and moves the developer upward. an apparatus according to any one of claims 1 to 4, characterized in that it is transportable Te. The toner replenishing portion is provided in the vicinity of the communicating portion in the conveying space located on the lower side in the gravitational direction, on the upstream side in the conveying direction of the developer moving toward the communicating portion. the developing device according to any one of the five. Wherein the communicating portion includes a developing device according to any one of claims 1 to 6, characterized in that updraft supply portion. An image forming apparatus characterized by using a developing device according to any one of claims 1 to 7.

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