JP2012027110A - Developing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device capable of improving toner suppliability to a toner supply roller and suppressing the degradation of printing quality by preventing the generation of toner aggregation in the vicinity of the toner supply roller, and to provide an image forming apparatus.SOLUTION: The developing device includes: a developer carrier which carries a developer and is rotated; a first developer conveying member which is added to the developer carrier and conveys the developer in the rotational axial direction of the developer carrier, while being rotated; a second developer conveying member which is added to the first developer conveying member and conveys the developer in the rotational axial direction of the developer carrier, while being rotated; and a stirring member in which at least one of the first developer conveying member and the second developer conveying member is rocked around a supporting point located outside in a radial direction with respect to a rotation center axis. The image forming apparatus includes the developing device.

Description

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

  2. Description of the Related Art Conventionally, in an image forming apparatus provided with a developing device that develops toner by attaching toner as a developer to an electrostatic latent image formed on an image carrier, in order to efficiently circulate the toner supplied into the developing device. The toner is agitated and conveyed in the opposite directions in the vicinity of a developing roller as a developer carrying member for adhering the toner to the image carrier or a toner supply roller as a developer supply member for supplying toner to the developing roller 2 Some have toner transport spirals arranged side by side (for example, see Patent Document 1).

JP 2004-117614 A

  In the developing device having such a configuration, uneven toner replenishment to the toner supply roller occurs at every rotation pitch of the spiral blade formed at regular intervals on the rotation shaft peripheral surface of the toner conveyance spiral. The toner conveying spiral is provided at a position away from the toner supply roller.

  For this reason, the developing device having the above-described configuration has a problem that the toner supply force to the toner supply roller is insufficient and toner aggregation occurs in the vicinity of the toner supply roller, resulting in a decrease in print quality.

  The present invention has been made in view of such circumstances, and an object of the present invention is to improve the toner supply force to the toner supply roller and prevent toner aggregation near the toner supply roller. Another object of the present invention is to provide a developing device and an image forming apparatus that can suppress a decrease in print quality.

  In order to solve the above problems, a developing device according to the present invention is provided with a developer carrying member that rotates while carrying a developer, and the developer carrying member, and the developer carrying the developer while rotating. A first developer conveying member that conveys the developer in the direction of the rotation axis of the body, and a second developer that is provided alongside the first developer conveying member and conveys the developer in the direction of the rotation axis of the developer carrier while rotating. At least one of the developer conveying member and the first developer conveying member or the second developer conveying member is a fulcrum located radially outward with respect to the rotation center axis. It is characterized by comprising a stirring member that swings.

  In addition, an image forming apparatus according to the present invention includes a developer carrying member that carries and rotates a developer, and a developer carrying member that is provided along with the developer carrying member, and rotates the developer while rotating in the direction of the rotation axis of the developer carrying member. A first developer conveying member that conveys the toner to the first developer conveying member, and a second developer conveying member that is provided alongside the first developer conveying member and conveys the developer in the direction of the rotation axis of the developer carrier while rotating. And at least one developer conveying member of the first developer conveying member or the second developer conveying member is a stirring member that swings at a fulcrum located radially outward with respect to the rotation center axis. It is characterized by providing the developing device provided with.

  According to the present invention, a developing device and an image forming apparatus capable of suppressing a decrease in print quality by improving the toner supply force to the toner supply roller and preventing toner aggregation near the toner supply roller. Can be provided.

It is a schematic sectional drawing for demonstrating the structure of a printer. It is a schematic block diagram for demonstrating the structure of a developing device. It is a perspective view for demonstrating the drive mechanism of each member in the image development part. It is the elements on larger scale for demonstrating the image development part edge part. FIG. 6 is a schematic diagram for explaining a configuration of a toner conveying spiral and an agitation shaft. It is a figure explaining the engagement mode with respect to the toner conveyance spiral of a stirring shaft. It is a figure for demonstrating the circulation mode of a toner. It is a figure explaining the locus drawn when a stirring shaft rotates. FIG. 6 is a schematic diagram for explaining a configuration of a toner conveying spiral and an agitation shaft. It is a general-view figure for demonstrating a guide member. It is a figure explaining the locus drawn when a stirring shaft rotates.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably.

[First Embodiment]
In the description of the first embodiment, first, a printer as an image forming apparatus to which the developing device according to the invention is applied will be described, and then the developing device according to the invention will be described.

  FIG. 1 is a schematic cross-sectional view for explaining a schematic configuration of a printer 100 according to the present invention. The printer 100 according to this embodiment is a color printer that forms a color image by superposing toners as four color developers of black (K), cyan (C), magenta (M), and yellow (Y). .

  The printer 100 is formed in a substantially S-shape starting from the medium tray 1, passing through the separation roller 2, the transport rollers 3a and 3b, the transfer belt 4, and the discharge rollers 7a, 7b, 7c and 7d, and the stacker 8 as an end point. Along the sheet transport path S, developing devices 10K, 10C, 10M, and 10Y corresponding to the respective toner colors and a fixing unit 6 are provided.

  The medium tray 1 stores sheets P stacked therein, and is detachably attached to the lower part of the printer 100. Then, the separation roller 2 provided on the upper side of the medium tray 1 takes out the sheets P stored in the medium tray 1 one by one from the uppermost portion and feeds them to the sheet conveyance path S.

  The transport rollers 3 a and 3 b correct the skew of the paper P fed from the separation roller 2 and transport the paper P to the transfer belt 4.

  The transfer belt 4 is an endless belt member that electrostatically attracts and conveys the paper P, and is paired with a drive roller 5a that rotates by a driving force transmitted from a driving unit (not shown) and the drive roller 5a. It is stretched by the tension roller 5b provided.

  The discharge rollers 7 a, 7 b, 7 c, and 7 d sandwich and convey the paper P that has passed through the fixing unit 6, and discharge the paper P to the stacker 8 that is formed using the outer casing of the printer 100.

  The exposure devices 9K, 9C, 9M, and 9Y are LED heads having a light emitting element such as an LED (Light Emitting Diode) element and a lens array, for example, and irradiation light output from the LED element based on image data is photosensitive. The body drums 11K, 11C, 11M, and 11Y are disposed so as to be imaged on the surface.

  The developing devices 10K, 10C, 10M, and 10Y are developing devices corresponding to the toner colors (black (K), cyan (C), magenta (M), and yellow (Y)). It is attached detachably. The developing devices 10K, 10C, 10M, and 10Y are latent images formed on the surfaces of the photosensitive drums 11K, 11C, 11M, and 11Y as image carriers by irradiation light emitted from the exposure devices 9K, 9C, 9M, and 9Y. A toner image is formed by attaching toner to the image.

  Further, transfer rollers 24K, 24C, 24M, and 24Y are disposed so as to face and contact each of the photosensitive drums 11K, 11C, 11M, and 11Y with the transfer belt 4 therebetween. A high voltage power source (not shown) is connected to the transfer rollers 24K, 24C, 24M, and 24Y, and toner images formed on the surfaces of the photosensitive drums 11K, 11C, 11M, and 11Y are transferred to the transfer rollers 24K, 24C, and 24Y, respectively. The image is transferred to the paper P by the bias voltage applied to 24M and 24Y. The developing devices 10K, 10C, 10M, and 10Y will be described in detail later.

  The fixing unit 6 is disposed on the downstream side of the sheet transport path S after the developing devices 10K, 10C, 10M, and 10Y, and includes a heat roller, a backup roller, a thermistor, and the like. For example, a heat roller is formed by coating a hollow cylindrical cored bar made of aluminum or the like with a heat-resistant elastic layer of silicone rubber and coating a PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) tube thereon. Is formed. In the core bar, for example, a heater such as a halogen lamp is provided. The backup roller, for example, has a structure in which a heat-resistant elastic layer of silicone rubber is coated on a metal core made of aluminum or the like and PFA is coated thereon, and is arranged so that a pressure contact portion is formed between the heat roller and the heat roller. Has been. The thermistor is means for detecting the surface temperature of the heat roller, and is disposed in the vicinity of the heat roller in a non-contact manner. The surface temperature of the heat roller is maintained at a predetermined temperature by controlling the heater based on the detection result of the surface temperature of the heat roller detected by the thermistor. The paper P on which the toner images formed in the developing devices 10K, 10C, 10M, and 10Y are transferred passes through the pressure contact portion formed by the heat roller and the backup roller maintained at a predetermined temperature, and thus the paper P Heat and pressure are applied to the toner, and the toner melts to fix the toner image.

  Although not shown in FIG. 1, as other members constituting the printer 100, the printer 100 includes a microprocessor, a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output port, a timer, and the like. A print control unit, an interface control unit that receives print data and a control command, controls the entire sequence of the printer 100, and executes a print operation; and temporarily stores print data input via the interface control unit Receiving memory, print data stored in the receiving memory, and editing the print data to display the image data editing memory for storing the formed image data (image data) and the status of the printer 100 For example, a display unit including a display device such as an LCD (Liquid Crystal Display), a user For example, an operation unit having an input means such as a touch panel for receiving instructions from the user, various sensors such as a paper position detection sensor, a temperature / humidity sensor, and a concentration sensor for monitoring the operation state of the printer 100, The image data stored in the image data editing memory is sent to the exposure devices 9K, 9C, 9M and 9Y, and the temperatures of the exposure device drive control unit and the fixing unit 6 for controlling the drive of the exposure devices 9K, 9C, 9M and 9Y are controlled. A temperature control unit for controlling, a paper transport motor control unit for controlling a drive motor for rotating each roller for transporting the paper P, a drive control unit for controlling a drive motor for rotating various rollers such as a photosensitive drum, Alternatively, a high-voltage power supply for applying a voltage to each roller is provided.

  Next, the developing devices 10K, 10C, 10M, and 10Y will be described. The developing devices 10K, 10C, 10M, and 10Y differ only in the stored toner color, and the other configurations are all the same. Therefore, in the following description, the developing devices 10K, 10C, 10M, and 10Y are expressed as the developing device 10, and the members constituting the developing device 10 are also described with the alphabetic suffixes indicating the toner colors omitted. . FIG. 2 is a schematic configuration diagram illustrating the configuration of the developing device 10.

  As shown in FIG. 2, the developing device 10 includes a developing unit 10 a that forms a toner image by attaching toner T ′ to a latent image formed on the surface of the photosensitive drum 11, and is attached to and detached from the developing unit 10 a. The toner storage container portion 10b is formed freely and stores toner T. Hereinafter, the internal configuration of the developing device 10 will be described.

  The developing device 10 includes a photosensitive drum 11, a developing roller 12 as a developer carrier, a developing blade 13 as a layer regulating member, a supply roller 14 as a supply member, a charging roller 15, and a cleaning blade 16. , Waste toner conveying spiral 17, toner blocking wall 18, storage container portion replenishing port 19, developing portion replenishing port 20, toner replenishing member 21, toner hopper 22, stirring blade 23, toner conveying spiral 30, 31 and a stirring shaft 32 are provided.

  The photosensitive drum 11 includes a conductive support and a photoconductive layer. For example, a charge generation layer as a photoconductive layer and a charge transport layer are sequentially stacked on a metal shaft such as aluminum as a conductive support. Is an organic photoconductor configured. Further, the photosensitive drum 11 forms a latent image based on the irradiation light emitted from the exposure device 9 while rotating in the direction of arrow a in the drawing.

  For example, urethane rubber in which carbon black is dispersed is disposed on the outer periphery of a metal shaft such as stainless steel, and the surface of the developing roller 12 is subjected to an isocyanate treatment. The developing roller 12 is disposed so as to be in pressure contact with the surface of the photosensitive drum 11 and supplies toner T ′ to the latent image formed on the photosensitive drum 11 while rotating in the direction b in the figure. Develop the image.

  The developing blade 13 is a plate-like member made of, for example, a metal plate such as stainless steel, and one end of the developing blade 13 is disposed at a position in contact with a predetermined position on the surface of the developing roller 13. The developing blade 13 regulates the layer thickness of the toner T ′ supplied from the supply roller 14.

  The supply roller 14 is provided with a semiconductive foamed silicone sponge layer on the outer periphery of a metal shaft such as stainless steel. The supply roller 14 is in contact with the developing roller 12 with a predetermined pressure, and supplies the toner T ′ supplied from the toner storage container 10 b to the developing roller 12 while rotating in the direction c in the drawing.

  The charging roller 15 is made of, for example, a metal shaft such as stainless steel and a semiconductive epichlorohydrin rubber. The charging roller 15 is in contact with the photosensitive drum 11 with a predetermined pressure, and uniformly charges the surface of the photosensitive drum 11 based on an applied voltage applied from a high voltage power source (not shown).

  The cleaning blade 16 is, for example, a urethane rubber member, and one end of the cleaning blade 16 is disposed at a position in contact with a predetermined position on the surface of the photosensitive drum 11. The cleaning blade 16 cleans the surface of the photosensitive drum 11 by scraping off the toner T ′ remaining on the surface of the photosensitive drum 11.

  The waste toner conveying spiral 17 is a coil spiral having a substantially rectangular cross section, and is formed with a length substantially the same as the axial length of the photosensitive drum 11. The toner T ′ scraped off by the cleaning blade 16 is not shown. Transport to waste toner transport box. The toner T 'transported to the waste toner transport box is collected in a waste toner collection container (not shown) by a transport means (not shown).

  The toner shielding wall 18 is a shielding wall that is disposed under the toner storage container portion 10b and prevents the toner T stored in the toner storage container portion 10b from falling. The toner blocking wall 18 is driven to open the storage container portion replenishment port 19 in accordance with the mounting operation of the toner storage container portion 10b to the developing portion 10a.

  The storage container portion replenishment port 19 is an opening formed in the lower portion of the toner storage container portion 10b, and the toner T dropped through the storage container portion replenishment port 19 is temporarily stored in the toner hopper 22 of the developing portion 10a. The

  The developing unit replenishment port 20 is an opening formed in the upper part of the developing unit 10a. When the developing unit replenishment port 20 is joined to the storage container unit replenishment port 19, the toner T dropped through the storage container replenishment port 19 is supplied to the developing unit 10a. Replenish.

  The toner replenishing member 21 is rotatably disposed immediately below the developing unit replenishing port 20 and receives the toner T ′ in a recess of the toner receiver.

  The toner hopper 22 is a space for temporarily storing the toner T ′ supplied from the toner storage container portion 10 b.

  The stirring blade 23 is a stirring member provided with a smooth wing-like member, and rotates by the weight of the weight provided at the radial end. Further, the stirring blade 23 is a toner remaining amount detecting means for detecting the remaining amount of toner by a reflection sensor disposed inside the printer 100 detecting the movement of its own weight from the top dead center to the bottom dead center of the blade member. Also serves.

  The toner conveyance spirals 30 and 31 are conveyance members that are provided alongside the developing roller 12 and convey the toner T ′ in the longitudinal direction that is the rotation axis direction of the developing roller 12 in accordance with the rotation operation in the d direction or e direction in the drawing. is there. The toner transport spiral 30 as the first developer transport member is disposed in the vicinity of the developing roller 12. Further, the toner transport spiral 31 as the second developer transport member is provided side by side with the toner transport spiral 30 at a position away from the developing roller 12.

  The agitation shaft 32 as an agitation member is a shaft member that swings with respect to the central axis of the rotation axis of the toner conveying spiral 31 with the outer side in the radial direction as a fulcrum.

  FIG. 3 is a perspective view for explaining a driving mechanism of each member in the developing device 10, particularly in the developing portion 10a.

  The developing unit 10a includes a drive gear 121 for rotating the developing roller 12, a drive gear 141 for rotating the supply roller 12 in the direction c in the drawing, and a toner gear spiral 30 for rotating in the direction d in the drawing. A driving gear 301, a driving gear 311 for rotating the toner conveying spiral 31 in the direction e in the figure, an idle gear 33 for engaging the driving gear 141, the driving gear 301, and the driving gear 311; The toner conveying spirals 30 and 31 rotate when the driving force transmitted to the driving gear 141 for rotating the supply roller 14 is transmitted via the idle gear 33. To do.

  By the way, the protrusion 232 on one end side of the stirring blade 23 driven in synchronization with the drive of the drive gear 231 contacts the blade member of the stirring blade 23, so that the stirring blade 23 rotates in the direction f in the figure. Further, the protrusion 233 on the other end side of the stirring blade 23 is a reflection plate member protruding from the outer wall of the developing unit 10 a and is located at a position facing the reflection sensor 34 disposed inside the printer 100.

  FIG. 4 is a partially enlarged view for explaining the end of the developing unit 10a when viewed from the direction of the arrow X in FIG. As described above, the toner conveying spiral 31 rotates when the driving force transmitted to the driving gear 141 for rotating the supply roller 14 is transmitted via the idle gear 33. At this time, the agitation shaft 32 engaged with the engaged portion 313 of the toner conveyance spiral 31 via the engagement portion 322 also rotates as the toner conveyance spiral 31 rotates.

  As shown in FIG. 5, such a toner transport spiral 31 has a toner transport blade portion 312 formed in a spiral shape on the peripheral surface of a shaft portion 311 as a rotation shaft having a length substantially the same as the length in the longitudinal direction of the developing roller 12. It has become a shape. Further, engaged portions 313 for engaging the stirring shaft 32 in a swingable manner are formed at both ends of the toner conveying spiral 31.

  The agitation shaft 32 is a shaft member formed in a substantially U shape, and is engaged with the toner conveying spiral 31 so as to be swingable through engagement portions 322 formed at both ends. FIG. 6 is a diagram for explaining the manner of engagement of the agitation shaft 32 with respect to the toner conveying spiral 31 when viewed from the direction of the arrow Y in FIG. As shown in FIG. 6, the engaged portion 313 of the toner conveyance spiral 31 is formed as an engagement hole radially outward with respect to the rotation center axis of the shaft member 311. The agitation shaft 32 and the toner conveying spiral 31 are engaged with each other by inserting the engagement portion 322 of the agitation shaft 32 into the engagement hole so as to be movable in the hole. As described above, the engaging portion 322 of the agitation shaft 32 is movable within the hole of the engaged portion 322 of the toner conveyance spiral 31, so that the shaft portion of the agitation shaft 32 is rotated with the rotation of the toner conveyance spiral 31. 321 can rotate around.

  Next, an image forming process of the printer 100 to which the developing device 10 having the above configuration is applied will be described.

  First, when print data is input to the printer 100 and image data based on the print data is generated, the printer 100 starts an image forming process. At the start of the image forming process, the paper P stored in the medium tray 1 is fed out to the paper transport path S one by one by the rotation of the separation roller 2 rotated by driving of a drive motor (not shown). Thereafter, the paper P is transported along the paper transport path S to the developing device 10 while the skew is corrected by the transport rollers 3a and 3b. Then, an image forming process described below is started at a predetermined timing until the paper P is conveyed to the developing device 10.

  When image data is generated for the printer 100, the photosensitive drum 11 rotates at a constant peripheral speed in the direction of arrow a in FIG. 2 by a driving force transmitted from a driving unit (not shown). The charging roller 15 provided in contact with the surface of the photosensitive drum 11 applies a charging bias of, for example, -1200 V applied from a high voltage power source (not shown) to the surface of the photosensitive drum 11, and Is uniformly charged. Next, the exposure device 9 provided facing the surface of the photosensitive drum 11 irradiates the photosensitive drum 11 with irradiation light corresponding to the image data, and the potential of the light irradiation portion is attenuated to form a latent image. It is formed.

  As described above, the developing roller 12 is disposed in close contact with the photosensitive drum 11, and a developing bias of −300 V, for example, is applied from a high voltage power source (not shown). For example, the developing roller 12 adsorbs and rotates and conveys the toner T ′ conveyed by the supply roller 14 to which a supply bias of −450 V is applied. In this rotational conveyance process, the developing blade 13 disposed downstream of the supply roller 14 and in pressure contact with the developing roller 12 adjusts the toner T ′ adsorbed on the developing roller 12 to a uniform thickness, thereby providing a toner layer. Form.

  The developing roller 12 reversely develops the latent image formed on the surface of the photosensitive drum 11 with the toner T ′. Since a bias voltage is applied between the conductive support of the photosensitive drum 11 and the developing roller 12 by a high voltage power source, the photosensitive drum 11 is formed between the photosensitive drum 11 and the developing roller 12. Electric field lines are generated along with the latent image. Therefore, the charged toner T ′ on the developing roller 12 adheres to the latent image portion on the photosensitive drum 11 due to electrostatic force, and a toner image is formed.

  Next, the toner image formed on the photosensitive drum 11 is transferred onto the paper P by a transfer roller 24 to which a transfer bias of +1100 V is applied, for example, by a high voltage power source (not shown).

  Thereafter, the paper P is conveyed to a fixing unit 6 having a heat roller and a backup roller. The paper P onto which the toner image has been transferred is controlled by a temperature control means (not shown) and conveyed to a pressure contact portion formed by a heat roller and a backup roller maintained at a predetermined surface temperature. Then, the toner T ′ is melted by the heat applied from the heat roller, and further pressed by the pressure contact portion, whereby the toner image is fixed on the paper P.

  The paper P on which the toner image has been fixed is nipped and conveyed by the discharge rollers 7a, 7b, 7c, and 7d, and then discharged to the stacker 8 to complete a series of image forming processes.

  Note that some toner T ′ may remain on the surface of the photosensitive drum 11 after the toner image is transferred. The remaining toner T ′ is removed by the cleaning blade 16. As described above, the cleaning blade 16 is disposed so as to contact a predetermined position on the surface of the photosensitive drum 11. By rotating the photosensitive drum 11 about the rotation axis while the cleaning blade 16 is in contact with the surface of the photosensitive drum 11, the toner T ′ remaining on the surface of the photosensitive drum 11 without being transferred is removed. . The waste toner transport spiral 17 transports the toner T ′ removed by the cleaning blade 16 to a waste toner transport box (not shown). The toner T ′ conveyed to the waste toner conveyance box is accommodated in a waste toner storage container and collected by a conveyance unit (not shown). The cleaned photosensitive drum 11 is repeatedly used in the next image forming process.

  In the image forming process, the toner conveying spiral 31 is rotated in the direction e in FIG. 3 by the driving force transmitted through the idle gear 33, and from the developing unit replenishment port 20 of the toner hopper central portion 22a in FIG. The replenished toner T ′ is conveyed in the g direction or the h direction. Further, the toner conveying spiral 30 rotates in the direction d in FIG. 3 by the driving force transmitted through the idle gear 33, and the toner T ′ existing in the toner hopper end portions 22b and 22c in FIG. Transport in the j direction. Therefore, in the toner hopper 22 of the developing unit 10a, the toner conveying spirals 30 and 31 rotate to move the toner hopper center 22a to the toner hopper end 22b or 22c, or from the toner hopper end 22b or 22c to the toner. A circulating flow of the toner T ′ to the hopper center portion 22a is generated.

  Further, when the toner T ′ existing above the toner conveying spirals 30 and 31 forms a mountain shape having a convex shape at the center as shown in FIG. 3, the stirring blade 23 moves in the k direction or the l direction. The toner T ′ is crushed and smoothed in the direction toward it. Here, for example, when the toner T ′ becomes less than a predetermined amount and the stirring blade 23 is released from the pressure of the toner T ′, the blade member of the stirring blade 23 has its center of gravity at the radial end and falls by its own weight. The bottom dead center is reached faster than the protrusion 232. At this time, the reflection sensor 34 provided in the printer 100 detects a change in the reflectance of the protrusion 233 due to the weight drop of the stirring blade 23 and notifies the print control unit (not shown) to that effect. Upon receiving the notification, the print control unit (not shown) controls a drive motor (not shown) to rotate the toner supply member 21 and prompts the toner T to be supplied to the developing unit 10a.

  In contrast, when the toner T ′ exceeds a predetermined amount and the pressure of the toner T ′ is applied to the stirring blade 23, the blade member of the stirring blade 23 is driven in synchronization with the drive gear 231. Because it is urged by and rotates, it does not fall by its own weight. At this time, the reflection sensor 34 provided in the printer 100 does not detect a change in the reflectance of the protrusion 233 due to the weight drop of the stirring blade 23 and notifies the print control unit (not shown) to that effect. Upon receiving the notification, the print control unit (not shown) controls the drive motor (not shown) to stop the rotation of the toner supply member 21 and stops the supply of the toner T to the developing unit 10a.

  Further, the shaft portion 321 of the agitation shaft 32 connected to the toner conveying spiral 31 moves when the toner conveying spiral 31 moves from the lower side to the upper side as shown in FIG. When moving from near the toner transport spiral 31 due to its own weight to the bottom when moving from above to below, it rotates so as to draw a locus away from the toner transport spiral 31 due to its own weight, and stirs the toner T ′.

  As described above, according to the first embodiment, as the toner conveyance spiral 31 rotates, the shaft portion 321 of the stirring shaft 32 draws a compact locus in the gap between the side wall of the developing unit 10 a and the stirring blade 23. In the position away from the toner conveying spiral 31, it rotates while drawing a locus passing through the vicinity of the supply roller 14, so that the toner supply force to the supply roller 14 can be effectively improved. It is possible to prevent toner aggregation occurring in the vicinity of the supply roller 14, to suppress a decrease in print quality, and to reduce the size of the apparatus main body.

[Second Embodiment]
2nd Embodiment demonstrates the form which provided the guide member which regulates the motion of the stirring shaft demonstrated in 1st Embodiment. In the description of the second embodiment, the same portions as those in the first embodiment are denoted by the same reference numerals, the description thereof is omitted, and different portions will be described.

  FIG. 9 is a schematic view for explaining the configuration of the toner conveying spiral 31 and the stirring shaft 32 ′ according to the second embodiment. FIG. 10 is a schematic view for explaining the guide member 35 that regulates the movement of the stirring shaft 32 '.

  As shown in FIG. 9 and FIG. 10, the guide member 35 has a bead shape and is formed on the inner wall of the developing unit 10 a that supports the toner conveying spiral 31. The end of the stirring shaft 32 ′ is formed in a crank shape so as to be slidable along the outer contour of the guide member 35.

  The shaft portion 321 ′ of the agitation shaft 32 connected to the toner conveyance spiral 31 is developed so as to draw the locus shown in FIG. 11 along the guide member 35 as the toner conveyance spiral 31 rotates in the direction e in FIG. When rotating on the side wall side of the portion 10a, it rotates in the vicinity of the toner conveyance spiral 31, and when rotating on the supply roller side, it rotates while drawing a locus passing through the vicinity of the supply roller away from the toner conveyance spiral 31 to stir the toner T ′. To do.

  As described above, according to the second embodiment, when the toner conveyance spiral 31 rotates, the shaft portion 321 ′ of the stirring shaft 32 ′ rotates in the vicinity of the toner conveyance spiral 31 when rotating on the side wall side of the developing unit 10a. When the toner is rotated on the supply roller side, the toner T ′ is agitated to draw a locus passing through the vicinity of the supply roller away from the toner conveying spiral 31, and the toner T ′ is effectively stirred. It is possible to improve, prevent toner aggregation occurring in the vicinity of the supply roller 14, suppress a decrease in print quality, and reduce the size of the apparatus main body.

  In the description of the present invention, it has been described that the transport direction of the toner T ′ by the toner transport spirals 30 and 31 is transported in the direction opposite to the longitudinal direction of the developing roller 12, but the present invention is not limited to this. Further, a configuration may be adopted in which the developing roller 12 is transported in the same direction with respect to the longitudinal direction.

  In the description of the present invention, the agitation shaft 32 is described as being provided in the toner conveyance spiral 31. However, the present invention is not limited to this, and the agitation shaft 32 may be provided in the toner conveyance spiral 30.

  Further, in the description of the present invention, a color printer has been described as an example of the image forming apparatus, but the present invention is not limited to this, and can be applied to, for example, a monochrome printer, a copier, a facsimile machine, an MFP, and the like.

DESCRIPTION OF SYMBOLS 1 Media tray 2 Separation roller 3a, 3b Conveyance roller 4 Transfer belt 5a Drive roller 5b Tension roller 6 Fixing unit 7a, 7b, 7c, 7d Discharge roller 8 Stacker 9K, 9C, 9M, 9Y Exposure apparatus 10K, 10C, 10M, 10Y Developing device 10a Developing unit 10b Toner storage container unit 11 Photoconductor drum 12 Developing roller 13 Developing blade 14 Supplying roller 15 Charging roller 16 Cleaning blade 17 Waste toner conveying spiral 18 Toner blocking wall 19 Storage container unit replenishing port 20 Developing unit replenishing port 21 Toner replenishing member 22 Toner hopper 23 Agitating blades 30, 31 Toner conveying spirals 32, 32 'Agitation shaft 33 Idle gear 34 Reflection sensor 35 Guide member

Claims (8)

A developer carrying member that carries the developer and rotates;
A first developer conveying member that is provided alongside the developer carrying member and conveys the developer in a rotation axis direction of the developer carrying member while rotating;
A second developer conveying member that is provided alongside the first developer conveying member and conveys the developer in the direction of the rotation axis of the developer carrier while rotating;
At least one developer conveying member of the first developer conveying member or the second developer conveying member includes a stirring member that swings at a fulcrum located radially outward with respect to the rotation center axis. A developing device characterized by the above. The first developer transport member and the second developer transport member transport the developer in opposite directions with respect to the rotation axis direction of the developer carrier. The developing device according to 1. The developing device according to claim 1, wherein the agitating member changes a moving distance of the developer conveying member from a rotation center axis with rotation of the developer conveying member. The developing device according to claim 3, wherein the agitating member has a swing range limited by a guide member formed on a support member that supports the developer conveying member. A developer carrying member that carries the developer and rotates;
A first developer conveying member that is provided alongside the developer carrying member and conveys the developer in a rotation axis direction of the developer carrying member while rotating;
A second developer conveying member that is provided alongside the first developer conveying member and conveys the developer in the direction of the rotation axis of the developer carrier while rotating;
At least one developer conveying member of the first developer conveying member or the second developer conveying member includes a stirring member that swings at a fulcrum located radially outward with respect to the rotation center axis. An image forming apparatus comprising the developing device. The first developer conveying member and the second developer conveying member convey the developer in opposite directions with respect to the rotation axis direction of the developer carrying member, respectively. The image forming apparatus described in 1. The image forming apparatus according to claim 5, wherein the stirring member changes a moving distance of the developer transport member from a rotation center axis with rotation of the developer transport member. . The image forming apparatus according to claim 7, wherein the agitating member is limited in a swing range by a guide member formed on a support member that supports the developer conveying member.