JP5245431B2 - Developing device and image forming apparatus - Google Patents

Description

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

  2. Description of the Related Art In recent years, image forming apparatuses such as copying machines and printers using an electrophotographic system have been reduced in size and cost. On the other hand, demands for performance are also increasing, and demands for productivity are particularly prominent.

  A developing device is incorporated in an electrophotographic image forming apparatus. The developing device develops the electrostatic latent image formed on the photoconductor into a toner image. Several developing methods have been proposed, and one of them is a two-component developing method. The two-component development method is a method of developing using a two-component developer in which a carrier and a toner are mixed.

  For example, in the following Patent Documents 1 and 2 as developing devices adopting the two-component development method, a developer holding body for holding a developer used for developing an electrostatic latent image and a supply to the developer holding body are provided. A supply conveyance unit that conveys the developer to be supplied, an agitation conveyance unit that conveys the developer to be supplied to the supply conveyance unit, and a recovery conveyance unit that conveys the developer recovered from the developer holder What is provided is described.

  In addition, as an advantageous configuration for reducing the thickness of the developing device, for example, Patent Document 3 below discloses a configuration in which a supply conveyance unit, an agitation conveyance unit, and a collection conveyance unit are arranged in a horizontal direction. In such a configuration of the developing device, the collection conveyance unit is arranged below the developer holder, the supply conveyance unit is arranged next to the collection conveyance unit in the horizontal direction, and the stirring conveyance unit is arranged next to the supply conveyance unit. It is arranged. Then, the developer collected by the collection conveyance unit is returned to the agitation conveyance unit via the supply conveyance unit.

JP 2001-290368 A JP 2001-290369 A JP 2006-251440 A

  In the present invention, when the developer collected from the developer holding member is returned from the collection conveyance unit arranged in the horizontal direction to the agitation conveyance unit via the supply conveyance unit, the developer is conveyed to the outside of the development region by the supply conveyance unit. Smoothly transfer the developer and the developer collected in the collection conveyance unit from the supply conveyance unit to the agitation conveyance unit through a common delivery unit provided in the partition wall of the supply conveyance unit and the agitation conveyance unit The purpose is to provide a mechanism that can

According to the first aspect of the present invention, a developer holder that rotates to develop the electrostatic latent image formed on the image carrier with the developer, and a developer to be supplied to the developer holder are conveyed. A supply and transport unit; a stirring and transport unit that transports the developer to be supplied to the supply and transport unit while stirring; and a recovery and transport unit that transports the developer recovered from the developer holder, the supply transport unit The agitating and conveying unit and the collecting and conveying unit are arranged in a horizontal direction with the supply and conveying unit interposed between the agitating and conveying unit and the collecting and conveying unit, and the collecting and conveying unit is disposed from the developer holder. The recovered developer is transferred to the supply transfer unit through a first transfer unit provided in a partition wall between the recovery transfer unit and the supply transfer unit, and the supply transfer unit is supplied from the stirring transfer unit. Transporting along the developer holder The first conveying unit includes a conveying unit and a second conveying unit configured to convey the developer taken in through the first delivery unit in a direction opposite to the first conveying unit, and the first conveying unit in the rotation axis direction of the developer holding member. The transport terminal portion of the means and the transport terminal portion of the second transport means are arranged in abutment with each other, and the developer merged at the abutting portion is provided in the partition wall between the supply transport unit and the agitation transport unit The first delivery section is provided upstream of the transport termination portion of the second transport means in the developer transport direction of the second transport means through the common second delivery section. The second delivery portion is provided at the abutting portion in the rotation axis direction of the developer holder.

Invention according to claim 2, in the developing apparatus according to claim 1 Symbol placement, the second transfer portion and the first transfer section is disposed in an abutting relationship in the axial direction of the developer carrier It is characterized by being.

The invention according to claim 3 is an image holding member, a latent image forming device that forms an electrostatic latent image on the image holding member, and an electrostatic latent image formed on the image holding member by the latent image forming device. A developing device that develops the electrostatic latent image formed on the image holding member, and a developer holding member that rotates to develop the developer with the developer, and supplies the developer holding member to the developer holding member. A supply conveyance unit that conveys the developer to be supplied, an agitation conveyance unit that conveys the developer to be supplied to the supply conveyance unit, and a recovery conveyance unit that conveys the developer collected from the developer holder. Provided, the supply transport unit, the stirring transport unit and the recovery transport unit are arranged in a horizontal direction with the supply transport unit sandwiched between the stirring transport unit and the recovery transport unit , the recovery transport unit, The developer recovered from the developer holder is transferred to the recovery transport unit and the supply. Passing to the supply conveyance section through a first transfer portion provided on the partition wall of the transport section, the supply conveyance unit, first for conveying the developer supplied from the agitation transport unit along the developer carrier The first conveying unit includes a conveying unit and a second conveying unit configured to convey the developer taken in through the first delivery unit in a direction opposite to the first conveying unit, and the first conveying unit in the rotation axis direction of the developer holding member. The transport terminal portion of the means and the transport terminal portion of the second transport means are arranged in abutment with each other, and the developer merged at the abutting portion is provided in the partition wall between the supply transport unit and the agitation transport unit The first delivery unit is passed through the common second delivery unit to the agitation transport unit, and the first delivery unit is located above the transport end part of the second transport unit in the developer transport direction by the second transport unit. Provided on a side, the second transfer unit is an image forming apparatus, characterized in that provided on the abutting portion in the rotation axis direction of the developer carrier.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. The technical scope of the present invention is not limited to the embodiments described below, and various modifications and improvements have been made within the scope of deriving specific effects obtained by the constituent requirements of the invention and combinations thereof. Also includes form.

  FIG. 1 is a schematic diagram showing a configuration example of an image forming apparatus to which the present invention is applied. The illustrated image forming apparatus 1 is a tandem digital color printer that forms an image according to an electrophotographic system.

  In this specification, the depth direction of the image forming apparatus 1 is defined as the X-axis direction, the width direction of the image forming apparatus 1 is defined as the Y-axis direction, and the height direction of the image forming apparatus 1 is defined as the Z-axis direction. In the figure, “○” in “○” means an arrow heading from the back of the paper to the front, and “×” in “○” is from the front of the paper. Means an arrow heading to Among these, the X-axis direction and the Y-axis direction are horizontal two-axis directions, and the Z-axis direction is a vertical direction (vertical direction). For this reason, the X-axis direction, the Y-axis direction, and the Z-axis direction are axes orthogonal to each other. The three orthogonal directions defined in the X-axis direction, the Y-axis direction, and the Z-axis direction defined here are used as needed to specify the structure and positional relationship of each part throughout the image forming apparatus 1. The X-axis direction is divided into an X direction and a −X direction depending on the direction. Similarly, the Y-axis direction is divided into a Y direction and a −Y direction, and the Z-axis direction is divided into a Z direction and a −Z direction.

  The image forming apparatus 1 takes in image data sent from an image reading device (not shown), a personal computer, or the like into the image processing unit 12 and performs predetermined image processing there, thereby yellow (Y), magenta (M), The image data is divided into image data (original reproduction color material gradation data) for four colors corresponding to each color component of cyan (C) and black (K). The image data for the four colors is visualized by the four image forming units 13Y, 13M, 13C, and 13K corresponding to the respective color components.

  Each of the image forming units 13Y, 13M, 13C, and 13K is arranged in parallel at a constant interval in the Y-axis direction. These four image forming units 13Y, 13M, 13C, and 13K are all configured similarly. That is, each of the image forming units 13Y, 13M, 13C, and 13K includes a photosensitive drum 15 that is driven to rotate counterclockwise in the figure, and a charging roll 16 that uniformly charges the surface of the photosensitive drum 15. The surface of the photosensitive drum 15 is exposed and scanned with a beam-shaped laser beam to form an electrostatic latent image, and the electrostatic latent image formed on the photosensitive drum 15 has a predetermined color. A developing device 17 for developing with toner and a cleaning device 18 for cleaning the surface of the photosensitive drum 15 are used. The rotation axis direction of the photosensitive drum 15 coincides with the X-axis direction.

  The latent image forming apparatus 14 is configured in common to the four image forming units 13Y, 13M, 13C, and 13K, and modulates four laser light sources (not shown) (for example, semiconductor laser elements) according to the image data of each color. The laser beams LB-Y, LB-M, LB-C, and LB-K are emitted from these laser light sources in accordance with the gradation data. The latent image forming apparatus 14 may be configured individually for each of a plurality of image forming units. The laser beams LB-Y, LB-M, LB-C, and LB-K emitted from the laser light source are applied to the polygon mirror 19 through an f-θ lens (not shown) and are deflected by the polygon mirror 19. . The laser beams LB-Y, LB-M, LB-C, and LB-K deflected by the polygon mirror 19 are oblique to the exposure position on the photosensitive drum 15 through an imaging lens (not shown) and a plurality of mirrors. Irradiation is performed from below, and scanning is performed in the rotation axis direction (X-axis direction) of the photosensitive drum 15.

  As described above, the latent image forming apparatus 14 forms an electrostatic latent image on the photosensitive drum 15 by irradiating laser light obliquely from below, so that four image formations located above the latent image forming apparatus 14 are formed. There is a risk that toner or the like may fall from the developing devices 17 of the units 13Y, 13M, 13C, and 13K and the latent image forming device 14 may be soiled. For this reason, the latent image forming apparatus 14 is hermetically sealed by a rectangular parallelepiped casing 20. Further, on the upper part of the housing 20, the above-described four laser beams LB-Y, LB-M, LB-C, and LB-K are exposed to the corresponding image forming units 13Y, 13M, 13C, and 13K. Transparent glass windows 21Y, 21M, 21C, and 21K as shield members are provided for transmission toward the body drum 15.

  From the image processing unit 12, the image data of each color component is parallel to the latent image forming apparatus 14 provided in common to the image forming units 13Y, 13M, 13C, and 13K for each color of Y, M, C, and K. Is output automatically. Laser beams LB-Y, LB-M, LB-C, and LB-K emitted according to the image data from the latent image forming device 14 are irradiated onto the surface of the corresponding photosensitive drum 15. At this time, the surface of the photosensitive drum 15 is exposed and scanned with laser light, whereby an electrostatic latent image corresponding to the image data is formed on the surface of the photosensitive drum 15. The electrostatic latent image formed on the photosensitive drum 15 is developed into toner images of Y, M, C, and K colors by developing devices 17Y, 17M, 17C, and 17K, respectively. However, when a black and white image is formed, only the K toner image is formed by the image forming unit 17K. Details of the developing device 17 will be described later.

  The toner images formed on the photosensitive drums 15 of the image forming units 13Y, 13M, 13C, and 13K are transferred onto the intermediate transfer belt 25 of the transfer unit 22 that is disposed over the image forming units 13Y, 13M, 13C, and 13K. On top of this, multiple transfer is performed by four primary transfer rolls 26Y, 26M, 26C, and 26K. These primary transfer rolls 26Y, 26M, 26C, and 26K are disposed on the back side of the intermediate transfer belt 25 corresponding to the photosensitive drum 15 of each of the image forming units 13Y, 13M, 13C, and 13K. A transfer bias power source (not shown) is connected to the primary transfer rolls 26Y, 26M, 26C, and 26K, and a transfer bias having a polarity opposite to the toner polarity applied to the toner by each of the developing devices 17Y, 17M, 17C, and 17K. Is applied at a predetermined timing.

  The intermediate transfer belt 25 is wound around the drive roll 27, the tension applying roll 24, and the support roll 28 with a predetermined tension. The intermediate transfer belt 25 is driven to circulate at a predetermined speed in the clockwise direction in the drawing according to the rotation of a drive roll 27 that is driven to rotate by a belt drive motor (not shown).

  The Y, M, C, and K toner images transferred onto the intermediate transfer belt 25 in multiple layers are subjected to image recording paper 30 by a secondary transfer roll 29 that is pressed against (contacted in a pressurized state) the support roll 28. Secondary transfer. The secondary transfer roll 29 is in pressure contact with the side of the support roll 28 and secondarily transfers the toner image onto the sheet 30 conveyed from below to above. The sheet 30 on which the toner image has been transferred by the secondary transfer roll 19 is conveyed to a fixing device 31 positioned above the secondary transfer roll 19. The paper 30 sent to the fixing device 31 is subjected to a fixing process by heating and pressurization and then discharged onto a discharge tray 33 by a discharge roll 32. The discharge tray 33 is provided on the upper part of the image forming apparatus 1.

  At the bottom of the image forming apparatus 1, a paper feed cassette 34 that can be attached to and detached from the image forming apparatus main body is provided. A sheet 30 of a predetermined size is stored in the sheet feeding cassette 34 in a stacked state. The paper 30 stored in the paper feed cassette 34 is sent to a paper feed path 37 by a paper feed roll 35 and a pair of rolls 36 for paper separation and transport, and is then carried along the paper feed path 37 to a registration roll 38. There it is temporarily stopped. The sheet conveyance path 37 is directed upward in the vertical direction. The sheet 30 once stopped by the registration roll 38 starts rotation of the registration roll 38 at a predetermined timing, thereby moving to the secondary transfer position of the intermediate transfer belt 25 (pressure contact position between the support roll 28 and the secondary transfer roll 29). It is sent.

  When the image forming apparatus 1 performs full-color double-sided copying, the sheet 30 with the image fixed on one side is not discharged as it is onto the discharge tray 33 by the discharge roll 32 but by a switching gate (not shown). The conveyance direction is switched, and the sheet is conveyed to the duplex conveyance unit 40 via the sheet conveyance roll pair 39. In the double-sided conveyance unit 40, the pair of conveyance rolls (not shown) provided along the conveyance path 41 are conveyed again to the registration roll 38 with the front and back sides of the paper 30 reversed. Then, after the image is transferred and fixed on the back surface of the paper 30, it is discharged onto the discharge tray 33.

  On the other hand, residual toner, paper dust, and the like are removed from the surface of the photosensitive drum 15 after the toner image transfer process is completed by the cleaning device 18 to prepare for the next image forming process. The cleaning device 18 includes a cleaning blade (not shown), and removes residual toner, paper dust, and the like on the photosensitive drum 15 by the cleaning blade. Further, residual toner, paper dust, and the like are removed from the surface of the intermediate transfer belt 25 after the toner image transfer process is completed by the cleaning device 43 to prepare for the next image forming process. The cleaning device 43 includes a cleaning brush 43a and a cleaning blade 43b, and residual toner and paper dust on the intermediate transfer belt 25 are removed by the cleaning brush 43a and the cleaning blade 43b.

  Further, a manual feed tray 47 capable of supplying an arbitrary sheet is attached to one side (left side in FIG. 1) of the image forming apparatus 1. The manual feed tray 47 is provided with a manual paper feed device 48 for feeding the paper 52 by a manual feed method. The manual paper feeder 48 is provided with a paper feed roll 49. The paper 52 fed from the manual feed tray 47 by the paper feed roll 49 is sent to the paper transport path 37 by a pair of transport rolls 50 provided on the downstream side of the paper feed roll 49, and is the same as the case of the paper 30 described above. To the registration roll 38.

  The developing device 17 is a two-component developing type developing device that performs development using, for example, a two-component developer composed of a non-magnetic toner and a magnetic carrier. Four toner cartridges 44Y, 44M, 44C, 44K are detachably (replaceable) provided on the upper part of the main body of the image forming apparatus 1. The toner cartridge 44Y is a container that stores Y toner, and the toner cartridge 44M is a container that stores M toner. The toner cartridge 44C is a container for storing C toner, and the toner cartridge 44K is a container for storing K toner. The toner stored in the toner cartridge 44Y is supplied to the developing device 17Y by a developer supply device (not shown), and the toner stored in the toner cartridge 44M is supplied to the developing device 17M by a developer supply device (not shown). It has become. The toner stored in the toner cartridge 44C is supplied to the developing device 17C by a developer supply device (not shown), and the toner stored in the toner cartridge 44K is supplied to the developing device 17K by a developer supply device (not shown). It is like that.

  Next, the configuration of the developing device according to the embodiment of the present invention will be described in detail. Note that the four developing devices 17Y, 17M, 17C, and 17K described above have the same configuration, and therefore, the addition of Y, M, C, and K color identification symbols is omitted in the following description.

  FIG. 2 is a schematic side view showing a configuration example of the developing device according to the embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of the developing device according to the embodiment of the present invention when viewed from the upper side. As illustrated, the developing device 17 mainly includes a developing device main body 71, a developing roll 72, a supply transport unit 73, a stirring transport unit 74, and a collection transport unit 75.

  The developing device main body 71 is a container that accommodates the developing roll 72, the supply conveyance unit 73, the agitation conveyance unit 74, and the collection conveyance unit 75. The developing device main body 71 is made of, for example, resin. In addition, the developing device main body 71 has, for example, a structure in which a plurality of main body components obtained by resin molding are combined by screws, adhesion, fitting, or the like, for example, a structure that is vertically divided or a structure that is vertically opened and closed. It has become.

  The developing roll 72 is provided as a developer holder. As illustrated in FIG. 2, the developing roll 72 is counterclockwise so that the photosensitive drum 15 is driven to rotate in the clockwise direction so as to be in the opposite direction (forward direction at the closest portion). Are driven to rotate. The rotation axis direction of the developing roll 72 coincides with the X-axis direction. For this reason, the photosensitive drum 15 and the developing roll 72 are arranged side by side in parallel along the X-axis direction. The developing roll 72 rotates at a constant speed in the counterclockwise direction in the figure while adsorbing and holding the two-component developer obtained by mixing the carrier and the toner to the outer peripheral surface of the roll with a magnetic force, The developer is transported to an adjacent development position. In this case, an electrostatic latent image is formed on the photosensitive drum 15 serving as an image holding member by the latent image forming device 4, and the electrostatic latent image is conveyed to the developing position by the clockwise rotation of the photosensitive drum 15. As a result, the electrostatic latent image on the photosensitive drum 15 is developed into a toner image.

  The supply conveyance unit 73 is a functional unit that conveys the developer to be supplied to the developing roll 72. The supply conveyance unit 73 includes a supply conveyance path 76 that extends in the X-axis direction, and a supply conveyance auger 77 that conveys the developer along the supply conveyance path 76. The supply transport auger 77 transports the developer along the developing roll 72 in order to supply the developer fed from the stirring transport section 74 to the supply transport section 73 to the developing roll 72. The supply and transfer auger 77 has a configuration in which a rotation drive shaft 78 and blade portions 79 and 80 are integrally provided. The rotary drive shaft 78 is formed in an elongated bar shape with a circular cross section. The rotation drive shaft 78 is disposed in the supply conveyance path 76 in parallel with the X-axis direction. The blade portions 79 and 80 are formed in a spiral shape. Further, the blades 79 and 80 have their spiral winding directions reversed so that when the rotary drive shaft 78 is rotated in one direction, the developer transport directions are opposite to each other in the X-axis direction. Is set to Specifically, the spiral winding direction of the blade portion 79 is set so that the developer is conveyed in the −X direction by the rotation of the rotation drive shaft 78, and the blade portion 80 supplies the developer X by the rotation of the rotation drive shaft 78. The spiral winding direction is set so as to convey in the direction. The blade part 79 is provided as a first transport unit, and the blade part 80 is provided as a second transport unit.

  The agitation transport unit 74 is a functional unit that transports the developer to be supplied to the supply transport unit 73 while stirring the developer. The agitating and conveying unit 74 includes an agitating and conveying path 81 that extends in the X-axis direction, and an agitating and conveying auger 82 that conveys the developer along the agitating and conveying path 81. The agitating / conveying auger 82 has a configuration in which a rotation drive shaft 83 and a blade portion 84 are integrally provided. The rotary drive shaft 83 is formed in an elongated rod shape with a circular cross section. The rotational drive shaft 83 is disposed in the agitation transport path 81 in parallel with the X-axis direction. The blade portion 84 is formed in a spiral shape. The blade portion 84 has a spiral winding direction set so as to convey the developer in the X direction by the rotation of the rotation drive shaft 83. For this reason, the spiral winding direction of the blade part 79 in the supply conveyance unit 73 and the spiral winding direction of the blade part 84 in the stirring conveyance unit 74 are set in opposite directions.

  The collection conveyance unit 75 is a functional unit that conveys the developer collected from the photosensitive drum 15. The collection conveyance unit 75 includes a collection conveyance path 85 extending in the X-axis direction, and a collection conveyance auger 86 that conveys the developer along the collection conveyance path 85. The collection conveyance auger 86 has a configuration in which a rotation drive shaft 87 and blade portions 88 and 89 are integrally provided. The rotary drive shaft 87 is formed in an elongated rod shape with a circular cross section. The rotational drive shaft 87 is disposed in the collection conveyance path 85 in parallel with the X-axis direction. The blade portions 88 and 89 are formed in a spiral shape. Further, the blade 88 and the blade 89 have their spiral winding directions reversed so that when the rotary drive shaft 87 is rotated in one direction, the directions in which the developer is conveyed in the X-axis direction are opposite to each other. Is set to Specifically, the spiral winding direction of the blade portion 88 is set so that the developer is conveyed in the −X direction by the rotation of the rotation drive shaft 87, and the blade portion 89 causes the developer X to be transferred by the rotation of the rotation drive shaft 87. The spiral winding direction is set so as to convey in the direction. The blade portion 89 acts to push back the developer conveyed in the −X direction by the blade portion 88 in the opposite X direction, so that the developer flows into the −X direction end of the collection conveyance portion 75. It is to prevent.

  The supply conveyance unit 73, the agitation conveyance unit 74, and the collection conveyance unit 75 are provided side by side in the horizontal direction (Y-axis direction) in the developing device main body 71. That is, as shown in the drawing, when viewed from the rotation axis direction of the developing roll 72, the agitating and conveying unit 74 is arranged on the right side (Y direction side) of the supply and conveying unit 73, and the recovery and conveying unit 75 is adjacent to the left side of the supplying and conveying unit 73. (-Y direction side). The horizontal direction described here refers to a direction perpendicular to the vertical direction (vertical direction) with the developing device 17 attached to the image forming apparatus 1.

  In the arrangement direction of the supply conveyance unit 73, the agitation conveyance unit 74, and the collection conveyance unit 75, the supply conveyance unit 73 and the collection conveyance unit 75 are partitioned by a partition wall 91 provided in the developing device main body 71. The partition 73 and the agitation transport unit 74 are partitioned by a partition wall 92 provided in the developing device main body 71. Further, the supply / conveyance unit 73 is disposed obliquely below and behind the developing roller 72, and the collection / conveying unit 75 is disposed below (substantially directly below) the developing roller 72. When viewed from the X-axis direction, the outer dimensions of the supply conveyance unit 73 and the agitation conveyance unit 74 are set to substantially the same dimension, and the outer dimension of the collection conveyance unit 75 is larger than the outer dimensions of the supply conveyance unit 73 and the agitation conveyance unit 74. Is also set to a small size (small diameter).

  Below the developing roll 72, the collection conveyance unit 75 is disposed so as to face the entire area of the developing roll 72 in the X-axis direction. The developing area of the developing roll 72 is defined by the length of the roll, for example, an area that is a predetermined dimension from both ends of the roll, but below the developing roll 72 from one end of the developing roll 72. In addition, the collecting and conveying unit 75 is long and extends in the −X direction. In the extended portion of the collection conveyance unit 75 that is separated from the developing roll 72, the conveyance end of the blade 88 and the conveyance termination of the blade 89 abut each other in the axial direction (X-axis direction) of the rotation drive shaft 87. The partition 91 is provided with a transfer portion (first transfer portion) 93 corresponding to the abutting portion. The conveyance termination portion of the blade portion 88 is a portion that is the most downstream side in the developer conveyance direction (−X direction) by the blade portion 88, and the conveyance termination portion of the blade portion 89 is a developer by the blade portion 89. The most downstream portion in the transport direction (X direction). The transfer part 93 is formed in a state in which a part of the partition wall 91 is notched in, for example, a concave shape or a U shape, or opened in a quadrangle, a circle, an ellipse, or the like when viewed from the Y-axis direction. . The transfer unit 93 is provided to transfer the developer from the collection transfer unit 75 to the supply transfer unit 73. For this reason, the supply conveyance path 76 and the collection conveyance path 85 partitioned by the partition wall 91 are spatially connected by the transfer section 93. For example, the center in the X-axis direction of the transfer portion 93 is disposed at substantially the same position as the center position between the conveyance end portions of the blade portions 88 and 89 in the X-axis direction.

  On the other hand, the supply conveyance unit 73 and the agitation conveyance unit 74 are disposed longer than the one end portion of the developing roll 72 in a state extending in the −X direction, like the collection conveyance unit 75. The ends in the −X direction of the supply conveyance unit 73, the agitation conveyance unit 74, and the collection conveyance unit 75 are arranged at the same position.

  In the extending portion of the supply conveyance unit 73 that is separated from the developing roll 72, the conveyance terminal portion of the blade portion 79 and the conveyance terminal portion of the blade portion 80 face each other in the axial direction (X-axis direction) of the rotation drive shaft 78. The partition wall 92 is provided with a transfer portion (second transfer portion) 94 corresponding to the abutting portion. The conveyance termination portion of the blade portion 79 is a portion that is the most downstream side in the developer conveyance direction (−X direction) by the blade portion 79, and the conveyance termination portion of the blade portion 80 is a developer by the blade portion 80. The most downstream portion in the transport direction (X direction). Similarly to the transfer unit 93 described above, the transfer unit 94 has a part of the partition wall 91 cut into, for example, a concave shape or a U shape, or a quadrangle, a circle, an ellipse, or the like when viewed from the Y-axis direction. It is formed in an open state. The delivery unit 94 is provided to deliver the developer from the supply conveyance unit 73 to the agitation conveyance unit 74. For this reason, the supply conveyance path 76 and the agitation conveyance path 81 partitioned by the partition wall 92 are spatially connected by the transfer section 94. For example, the center in the X-axis direction of the transfer portion 94 is disposed at substantially the same position as the center position between the conveyance end portions of the blade portions 79 and 90 in the X-axis direction. Further, the above-described delivery unit 93 is provided on the upstream side (left side in FIG. 3) with respect to the conveyance end portion of the blade unit 80 in the developer conveyance direction (X direction) by the blade unit 80.

  Further, in the X-axis direction, the position of the transfer portion 93 provided on the partition wall 91 and the position of the transfer portion 94 provided on the partition wall 92 are set so as to be shifted from each other. In other words, the position of the transfer section 94 in the X-axis direction is such that the developer transported by the blade section 79 and the developer transported by the blade section 80 join together in the vicinity of the transfer section 94 as the rotary drive shaft 78 rotates. Thus, the position is set so as to be shifted from the delivery portion 93 so that the guide portion is guided (extruded) to the delivery portion 94 side. Specifically, considering the position of the transfer unit 93 as a reference, the position of the transfer unit 94 is set in a state shifted in the X direction. Further, the X-direction end of the transfer portion 93 and the −X-direction end of the transfer portion 94 are arranged at substantially the same position in the X-axis direction. That is, the delivery part 93 and the delivery part 94 are arranged in a positional relationship adjacent to each other in the X-axis direction. For this reason, in the X-axis direction, the delivery part 93 and the delivery part 94 are arranged in a state where they do not overlap (in other words, the position is completely shifted). Moreover, the conveyance terminal part of the blade | wing part 80 is arrange | positioned in the X direction position at the substantially the same position as the X direction end of the delivery part 93, or several millimeters more than it.

  FIG. 4 is a schematic diagram illustrating a developer conveyance path in the developing device in a plan view. In FIG. 4, a developer taking-in portion 95 is provided at the −X direction end of the stirring and conveying portion 74. The developer taking-in part 95 is a part that takes in the developer replenished by a developer replenishing device (not shown) into the agitation transport path 81. The developer taking-in part 95 is formed in an open state, for example. On the other hand, the developer discharge portion of the developer replenishing device (not shown) is formed in a state of opening downward. By connecting this developer discharge portion to the developer intake portion 95, development is performed in a dropping manner. The developer is supplied from the agent supply device to the developing device 17.

  The developer taken in from the developer take-in portion 95 is conveyed in the X direction along the agitating / conveying path 81 by the agitating / conveying auger 82 by the agitating / conveying portion 74, and at the X direction end side of the agitating and conveying portion 74 Is taken into the supply conveyance unit 73 through the transfer unit 96 provided in

  The developer taken in from the delivery unit 96 is conveyed in the −X direction along the supply conveyance path 76 by the rotation of the supply conveyance auger 77 in the supply conveyance unit 73, and a necessary amount of developer is developed on the developing roll during this conveyance. 72. At that time, surplus developer that has not been supplied to the developing roll 72 (hereinafter also referred to as “surplus developer”) is transported to the outside of the −X direction development area.

  Further, a part of the developer supplied to the developing roll 72 is collected by the collecting and conveying unit 75 without being used for developing the electrostatic latent image. The developer is collected from the developing roll 72 by, for example, a method of peeling the developer from the developing roll 72 using a repulsive magnetic pole or a method of forcibly peeling the developer from the developing roll 72 using a peeling member. It is. The developer recovered by the recovery transport unit 75 (hereinafter also referred to as “recovered developer”) is transported in the −X direction along the recovery transport path 85 by the rotational drive of the recovery transport auger 86, and the recovery transport unit 75 is taken into the supply conveyance unit 73 through the transfer unit 93 provided on the end side in the −X direction.

  Here, as described above, the surplus developer transported to the outside of the development region by the supply transport unit 73 is transported to the transport end portion of the blade portion 79 by the rotational drive of the supply transport auger 77. Further, as described above, the collected developer taken into the supply conveyance unit 73 from the collection conveyance unit 75 through the transfer unit 93 is conveyed to the conveyance end portion of the blade unit 80 by the rotational drive of the supply conveyance auger 77. For this reason, the surplus developer and the recovered developer are merged (mixed) at the abutting portions of the blade portions 79 and 80.

  Further, the developer merged as described above (hereinafter also referred to as “merged developer”) is taken into the agitation conveyance unit 74 from the supply conveyance unit 73 through the common transfer unit 94. The merged developer taken in from the delivery unit 94 is conveyed in the X direction along the agitating and conveying path 81 by the agitating and conveying auger 82 being rotationally driven by the agitating and conveying auger 82 in the agitating and conveying unit 74 together with the developer taken in from the developer incorporating unit 95 described above. Is done. As a result, the developer is conveyed cyclically in the developing device 17.

  At that time, when the developer is taken into the supply conveyance unit 73 from the collection conveyance unit 75, for example, the developer collected by the collection conveyance unit 75 joins the developer being conveyed by the blade unit 79. If the position is set to be shifted in the X direction, the flow of the developer being conveyed by the blade 79 becomes a barrier, and the delivery of the developer is hindered. For this reason, the developer collected by the collection conveyance unit 75 stays in the transfer unit 93 and is not smoothly taken into the supply conveyance unit 73.

  On the other hand, in the developing device 17 according to the embodiment of the present invention, as described above, in the developer transport direction (X direction) by the blade portion 80, the delivery portion is upstream of the transport end portion of the blade portion 80. 93 is provided, so that the delivery of the developer from the collection conveyance unit 75 to the supply conveyance unit 73 is not hindered by the developer being conveyed by the blade unit 79. Further, since the developer taken in from the delivery unit 93 is conveyed by the dedicated blade part 80, the developer does not stay in the delivery unit 93. For this reason, the developer is smoothly transferred between the collection conveyance unit 75 and the supply conveyance unit 73.

  Further, in the developing device 17 according to the embodiment of the present invention, the position of the transfer portion 93 and the position of the transfer portion 94 are set so as to be shifted from each other in the X-axis direction that is the rotation axis direction of the developing roll 72. Therefore, the partition wall 91 that partitions the supply conveyance unit 73 and the collection conveyance unit 75 serves as a barrier, and the outflow direction of the merged developer is limited to the Y direction. Therefore, the merged developer merged in the supply conveyance unit 73 is forcibly pushed out to the delivery unit 94 in response to the conveyance force in the −X direction by the blade portion 79 and the conveyance force in the X direction by the blade portion 80. For this reason, the merged developer merged in the supply conveyance unit 73 is smoothly transferred to the agitation conveyance unit 74 through the common transfer unit 94 without flowing back to the collection conveyance unit 75 side.

  Furthermore, in the developing device 17 according to the embodiment of the present invention, the size of the device in the X-axis direction is reduced by arranging the transfer portion 93 and the transfer portion 94 adjacent to each other in the X-axis direction. However, the present invention is not limited to this, and the transfer unit 93 and the transfer unit 94 may be arranged apart from each other by a predetermined distance (for example, about several mm to several tens mm) in the X-axis direction.

  In addition, the present invention is not limited to a tandem type image forming apparatus including a plurality of photosensitive drums, but can be similarly applied to an image forming apparatus including a single photosensitive drum.

1 is a schematic diagram illustrating a configuration example of an image forming apparatus to which the present invention is applied. FIG. 2 is a schematic side view illustrating a configuration example of a developing device according to an embodiment of the present invention. 1 is a schematic cross-sectional view of a developing device according to an embodiment of the present invention when viewed from above in a plan view. FIG. 3 is a schematic diagram illustrating a developer conveyance path in a developing device in a plan view.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 14 ... Latent image forming apparatus, 15 ... Photoconductor drum, 17 ... Developing apparatus, 71 ... Developing apparatus main body, 72 ... Developing roll, 73 ... Supply conveyance part, 74 ... Agitation conveyance part, 75 ... Collection | recovery Conveying section, 76 ... supply conveying path, 77 ... supply conveying auger, 78 ... rotation driving shaft, 79 ... blade section, 80 ... blade section, 81 ... stirring conveying path, 82 ... stirring conveying auger, 83 ... rotation driving shaft, 84 DESCRIPTION OF REFERENCE SYMBOLS: Blade part, 85 ... Collection conveyance path, 86 ... Collection conveyance auger, 87 ... Rotation drive shaft, 88 ... Blade part, 89 ... Blade part, 91 ... Partition, 92 ... Partition, 93 ... Delivery part, 94 ... Delivery part, 95 ... Developer take-in section, 96 ... Transfer section

Claims (3)

A developer holder that is rotationally driven to develop the electrostatic latent image formed on the image holder with a developer;
A supply transport unit for transporting the developer to be supplied to the developer holder;
An agitating and conveying unit for conveying the developer to be supplied to the supply and conveying unit while agitating;
A recovery transport unit that transports the developer recovered from the developer holder,
The supply conveyance unit, the agitation conveyance unit, and the recovery conveyance unit are arranged in a horizontal direction with the supply conveyance unit interposed between the agitation conveyance unit and the collection conveyance unit ,
The recovery transport unit transfers the developer recovered from the developer holder to the supply transport unit through a first transfer unit provided in a partition wall between the recovery transport unit and the supply transport unit,
The supply conveyance unit includes a first conveyance unit that conveys the developer supplied from the agitation conveyance unit along the developer holder, and the developer taken in through the first delivery unit. A second conveying unit that conveys the toner conveying member in a direction opposite to that of the developer holding member, and a conveying terminal part of the first conveying unit and a conveying terminal part of the second conveying unit that face each other in the rotation axis direction of the developer holder. The developer that has been arranged and merged at the abutting portion is delivered to the agitation transport unit through a common second delivery unit provided in a partition wall between the supply transport unit and the agitation transport unit,
The first delivery unit is provided on the upstream side of the conveyance termination portion of the second conveyance unit in the developer conveyance direction by the second conveyance unit,
The developing device according to claim 1, wherein the second delivery portion is provided at the abutting portion in a rotation axis direction of the developer holding member . The developing device according to claim 1 Symbol placement,
The developing device, wherein the first delivery part and the second delivery part are arranged adjacent to each other in the rotation axis direction of the developer holding member. An image carrier,
A latent image forming apparatus for forming an electrostatic latent image on the image carrier;
A developing device for developing the electrostatic latent image formed on the image carrier by the latent image forming device,
The developing device includes:
A developer holder that is rotationally driven to develop the electrostatic latent image formed on the image holder with a developer;
A supply transport unit for transporting the developer to be supplied to the developer holder;
An agitating and conveying unit for conveying the developer to be supplied to the supply and conveying unit while agitating;
A recovery transport unit that transports the developer recovered from the developer holder,
The supply conveyance unit, the agitation conveyance unit, and the recovery conveyance unit are arranged in a horizontal direction with the supply conveyance unit interposed between the agitation conveyance unit and the collection conveyance unit ,
The recovery transport unit transfers the developer recovered from the developer holder to the supply transport unit through a first transfer unit provided in a partition wall between the recovery transport unit and the supply transport unit,
The supply conveyance unit includes a first conveyance unit that conveys the developer supplied from the agitation conveyance unit along the developer holder, and the developer taken in through the first delivery unit. A second conveying unit that conveys the toner conveying member in a direction opposite to that of the developer holding member, and a conveying terminal part of the first conveying unit and a conveying terminal part of the second conveying unit that face each other in the rotation axis direction of the developer holder. The developer that has been arranged and merged at the abutting portion is delivered to the agitation transport unit through a common second delivery unit provided in a partition wall between the supply transport unit and the agitation transport unit,
The first delivery unit is provided on the upstream side of the conveyance termination portion of the second conveyance unit in the developer conveyance direction by the second conveyance unit,
The image forming apparatus, wherein the second delivery portion is provided at the abutting portion in a rotation axis direction of the developer holder .

Images