JP2005316160A - Developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To downsize a developing device by simplifying a gear train rotating two or more spiral augers, to reduce cost, to form a good toner image on a photoreceptor, and to prevent excessive recovery or insufficient recovery of developer in a developing device. <P>SOLUTION: The developer can be circulated in a housing 150 without having an idle gear between gears 166 and 168 attached to rotating shafts 162 of the spiral augers 90 and 92 since the spiral directions are the same in the spiral augers 90 and 92 of respective developing apparatuses 18Y to K. Here, by making the spiral directions of the spiral augers 90 and 92 the same, when a rotary 39 is rotated, the developer in the housing 150 is biased in one direction by the spiral augers 90 and 92. Therefore, the amount of developer inside the housing 150 is made uniform by rotating the spiral augers 90 and 92 by driving force of a motor provided in a developing position by moving the respective developing apparatuses 18Y to K to the developing position when the job is finished. Thus, an image without any void or unevenness in density can be formed in a next job. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a developing device in which each developing device is sequentially opposed to an image carrier by rotation of a rotating member supporting a plurality of developing devices, and each developing device sequentially forms a toner image on the image carrier.

  In a rotary developing device in which a plurality of developing devices are supported by a rotary, the rotary devices are rotated so that each developing device is sequentially opposed to one photoconductor, and each developing device sequentially forms a toner image on one photoconductor. A method of recovering excess developer in the developing device by utilizing the rotation of the rotary has been devised (see, for example, Patent Document 1).

  By the way, in the developing device, the developer in the developing device is conveyed along the developing roll by the rotation of the spiral auger. In the rotary developing device, the developer in the developing device is rotated by the spiral auger. Even if the rotary is not rotated, it is conveyed along the developing roll by the spiral auger.

  In Patent Document 1, the spiral directions of the two spiral augers are set in opposite directions so that when the rotary rotates, the developer in the developing device is circulated along the developing roll by the spiral auger. For this reason, during the rotation of the rotary, the amount of developer in the developing device becomes uniform without being biased, so that a good toner image without white spots can be formed.

However, in order to circulate the developer in the developing device by two spiral augers whose vortex directions are opposite directions, the two spiral augers must be rotated in the same direction. An idle gear must be provided between the two gears respectively attached to the rotating shaft. Therefore, there has been a problem that the developing device becomes large and the cost increases.
JP 9-218575 A

  The present invention has been made in view of the above facts, and by simplifying a gear train for rotating a plurality of stirring members, the developing device can be downsized and the cost can be reduced. In addition, an object is to form a good toner image on the image carrier and to prevent excessive recovery and insufficient recovery of the developer in the developing device.

  The developing device according to claim 1, wherein a plurality of stirring members each having a spiral stirring blade formed on a rotating shaft circulates while stirring the developer along the developing roll, and the developing roll A plurality of developing units for developing the image carrier with the developer agitated by the member, and a plurality of recovering the excess developer in the developing unit from a recovery port facing the developer circulation path in the developing unit. By supporting and rotating the collecting unit, the plurality of developing units and the plurality of collecting units, each developing unit is sequentially opposed to the image carrier, and the excess developer in each developing unit is sequentially collected. A rotating body that collects the rotating body, a rotating body driving unit that rotates the rotating body in one direction, and a stirring member that rotates the plurality of stirring members of each developer rotated to a developing position facing the image carrier. A developing device comprising: The stirrer blades of the plurality of stirrers have the same swirling direction, and the swirl direction is sent in a direction in which the developer in the developing device is separated from the recovery port by the rotational force of the rotating body in the one direction. And a control unit that drives the rotating member driving unit to move each developing device to the developing position and drives the stirring member driving unit between jobs.

  In the developing device according to claim 1, a plurality of developing devices each having a spiral stirring blade formed on a rotating shaft are supported by a rotating body, and the rotating body is rotated in one direction by a rotating body driving unit. Each developer is sequentially opposed to the image carrier. When each developing device is rotated to a position facing the image carrier, the plurality of stirring members are rotated by the stirring member driving means, the developer is circulated while being stirred along the developing roll, and the developing roll However, the image carrier is developed with the developer stirred by the stirring member.

  Further, a plurality of recovery units are supported by the rotating body, and the rotating body is rotated in one direction by the rotating body driving means, so that excess developer in the developing device faces the developer circulation path. It is collected from the collection port to the collection unit.

  Here, the spiral directions of the stirring blades of the plurality of stirring members provided in each developing device are the same. For this reason, in order to circulate the developer in the developing device, it is only necessary to rotate the plurality of stirring members in the reverse direction. If the gears are respectively attached to the rotation shafts of the plurality of stirring members and the gears are directly meshed with each other, good. That is, it is not necessary to interpose an idle gear in a gear train for rotating a plurality of stirring members, and the gear train can be simplified, so that the developing device can be reduced in size and the cost can be reduced.

  In addition, by making the swirl directions of the plurality of stirring members the same, when the rotating body rotates in one direction, the developer in the developing device is sent in the same direction by the plurality of stirring members. Is configured such that the developer in the developing device is sent in a direction away from the recovery port by rotating the rotating body in one direction to prevent excessive recovery of the developer in the developing device.

  Here, since the stirring member is configured so that the developer in the developing device is biased in one direction while the rotating body is rotating, the developer cannot be uniformly supplied to the entire developing roll if the development is performed as it is, and the image White spots occur. For this reason, the control means drives the rotating body driving means between the jobs to rotate the rotating body, moves each developing device to the developing position facing the image carrier, and drives the stirring member. The developer that is biased in the direction away from the recovery port by driving the means is sent to the recovery port side, and the amount of the developer is made uniform over the circulation path.

  Thus, during development, the developer can be uniformly supplied to the entire developing roll, and the occurrence of white spots in the image can be prevented. Further, excessive developer can be recovered from the recovery port during rotation of the rotating body, and insufficient recovery of the developer can be prevented.

  A developing device according to a second aspect is the developing device according to the first aspect, wherein the developing device includes a home position sensor that detects a home position of the rotating body, and the control unit receives a detection signal from the home position sensor. When receiving, the rotating member driving means is driven, each developing device is moved to the developing position, and the stirring member driving means is driven.

  In the developing device according to claim 2, when the rotating body is rotated to the home position and detected by the home position sensor, the control unit drives the rotating body driving unit to rotate the rotating body to rotate each developing device. The developing position is moved, and the stirring member driving means is driven to rotate the stirring member. As a result, the amount of developer biased in one direction is made uniform every time the job is completed, so that a good toner image with little variation in toner density can be formed on the image carrier in the next job.

  The developing device according to claim 3 is the developing device according to claim 1, wherein the control unit drives the rotating body driving unit to move each developing unit to the developing position after the monochrome job is completed. The stirring member driving means is driven.

  When a single color job is performed, except for one developing device that performs development, the stirring member rotates without rotating the stirring member. It will be biased in the direction. For this reason, in the developing device according to the third aspect, the control means executes a uniforming operation for eliminating the bias of the developer after the monochromatic job is completed. Thus, even if a full color job is performed after a single color job, a good image without white spots can be formed.

  The developing device according to claim 4 is the developing device according to claim 1, wherein the control unit drives the rotating body in a recovery mode for recovering excess developer in a predetermined developing device. Driving the developing unit to the developing position to drive the stirring member driving unit, and moving each developing unit other than the developing unit to the developing position to drive the stirring member driving unit. Features.

  5. The developing device according to claim 4, wherein in the recovery mode for recovering excess developer in a predetermined developing device, the control means drives the rotating body driving means to rotate the rotating body, and the developing device Is moved to the developing position, and the stirring member driving means is driven to rotate the stirring member. As a result, the developer is sent to the collection port side, so that excess developer is collected in the collection unit.

  Here, when the developing devices other than the predetermined developing device are swung around the rotation axis of the rotating body without rotating the stirring member in the collecting mode, the developer is biased in one direction. For this reason, in the recovery mode, the control means moves not only the predetermined developing device but all the developing devices to the developing position and drives the stirring member driving means to rotate the stirring member. This makes it possible to form a good image without white spots in a job after the collection mode.

  The developing device according to claim 5 is the developing device according to any one of claims 1 to 4, wherein the control means drives the rotating body when each developing device is rotated to the developing position. The stirring member driving means is driven by temporarily stopping the means.

  According to a fifth aspect of the present invention, the control means stops the rotating body driving means once each developing device has been rotated to the developing position to stop the rotation of the rotating body, and then drives the stirring member driving means. The stirring member is rotated continuously. As a result, the developer amount is sufficiently uniformized.

  A developing device according to a sixth aspect is the developing device according to any one of the first to fifth aspects, wherein the recovery port is disposed in the developing device when the rotating body rotates in the one direction. The developer is provided at the upstream end in the direction fed by the stirring member.

  7. The developing device according to claim 6, wherein when the rotating body rotates in one direction, an upstream end in a direction in which the developer in the developing device is fed by the stirring member, that is, an end opposite to the direction in which the developer is biased. In addition, a recovery port is provided. For this reason, since the developer does not flow into the recovery port when the developer is biased in one direction with the rotation of the rotating body, excessive recovery of the developer can be prevented.

  Since the present invention has the above configuration, the gear train for rotating the plurality of stirring members can be simplified. As a result, the developing device can be miniaturized and the cost can be reduced. In addition, it is possible to form a good toner image on the image carrier and to prevent excessive and insufficient recovery of the developer in the developing device.

  An embodiment of the present invention will be described below with reference to the drawings.

  1 and 2 show a four-cycle full-color printer 10 as an image forming apparatus. Inside the printer 10, a photosensitive drum 12 as an image carrier is rotatably disposed at an upper right part slightly from the center. As this photosensitive drum 12, for example, a drum made of a conductive cylinder having a diameter of about 47 mm whose surface is coated with a photosensitive layer made of OPC or the like is used. It is rotationally driven at a process speed of about 150 mm / sec.

  The surface of the photosensitive drum 12 is charged to a predetermined potential by a charging roll 14 disposed almost directly below the photosensitive drum 12, and then an ROS 16 (Raster Output Scanner) serving as an exposure device disposed below the charging roll 14. ), Image exposure with a laser beam (LB) is performed, and an electrostatic latent image corresponding to image information is formed.

  The electrostatic latent image formed on the photosensitive drum 12 passes through the developing units 18Y, 18M, 18C, and 18K for each color of yellow (Y), magenta (M), cyan (C), and black (K) in the circumferential direction. The toner is developed by a rotary developing device 18 arranged along the toner image to be a toner image of a predetermined color.

  At this time, charging, exposure, and development processes are repeated a predetermined number of times on the surface of the photosensitive drum 12 in accordance with the color of the image to be formed. In the rotary developing device 18, the corresponding color developing devices 18 </ b> Y, 18 </ b> M, 18 </ b> C, and 18 </ b> K move to a developing position facing the photosensitive drum 12.

  For example, when a full-color image is formed, the charging, exposing, and developing processes are performed on the surface of the photosensitive drum 12 in yellow (Y), magenta (M), cyan (C), and black (K) colors. The toner image corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K) is sequentially formed on the surface of the photosensitive drum 12. .

  When the toner image is formed, the number of rotations of the photosensitive drum 12 varies depending on the size of the image. For example, in the case of A4 size, one image is obtained by rotating the photosensitive drum 12 three times. It is formed. That is, a toner image corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K) is formed on the surface of the photosensitive drum 12 every time the photosensitive drum 12 rotates three times. Is done.

  The yellow (Y), magenta (M), cyan (C), and black (K) toner images sequentially formed on the photosensitive drum 12 are transferred onto the outer periphery of the photosensitive drum 12 as an intermediate transfer member. At the primary transfer position where the belt 20 is wound, the primary transfer is performed by the primary transfer roll 22 while being superimposed on the intermediate transfer belt 20.

  The yellow (Y), magenta (M), cyan (C), and black (K) toner images transferred in multiple onto the intermediate transfer belt 20 are recorded on a recording sheet 24 fed at a predetermined timing. Secondary transfer is collectively performed by the secondary transfer roll 26.

  On the other hand, the recording paper 24 is fed from a paper feed cassette 28 disposed at the bottom of the printer 10 by a pickup roll 30 and is fed one by one by a feed roll 32 and a retard roll 34 to be registered. The roller 36 is conveyed to the secondary transfer position of the intermediate transfer belt 20 in synchronization with the toner image transferred onto the intermediate transfer belt 20.

  The intermediate transfer belt 20 includes a wrap-in roll 38 that specifies the wrap position of the intermediate transfer belt 20 on the upstream side in the rotational direction of the photosensitive drum 12 and a toner image formed on the photosensitive drum 12 as an intermediate transfer belt. A primary transfer roll 22 that is transferred onto the intermediate transfer belt 20, a wrap-out roll 40 that specifies the wrap position of the intermediate transfer belt 20 on the downstream side of the wrap position, and a backup that contacts the secondary transfer roll 26 via the intermediate transfer belt 20. The roll 42, the first cleaning backup roll 46 facing the cleaning device 44 of the intermediate transfer belt 20, and the second cleaning backup roll 48 are stretched with a predetermined tension and have a predetermined process speed (about 150 mm / sec), for example, as the photosensitive drum 12 rotates. It is driven Te.

  Here, in order to reduce the size of the printer 10, the intermediate transfer belt 20 is configured such that the cross-sectional shape on which the intermediate transfer belt 20 is stretched becomes a flat and elongated substantially trapezoidal shape.

  The intermediate transfer belt 20 includes a photosensitive drum 12, a charging roll 14, an intermediate transfer belt 20, a plurality of rolls 22, 38, 40, 42, 46, and 48 that stretch the intermediate transfer belt 20, and an intermediate transfer belt. The image forming unit 52 is constituted by a cleaning device 44 for 20 and a cleaning device 78 for the photosensitive drum 12 described later, and is integrally provided.

  For this reason, the entire image forming unit 52 can be removed from the printer 10 by opening the upper cover 54 of the printer 10 and lifting the handle (not shown) provided on the upper portion of the image forming unit 52 by hand.

  On the other hand, the cleaning device 44 for the intermediate transfer belt 20 includes a scraper 58 disposed so as to come into contact with the surface of the intermediate transfer belt 20 stretched by the first cleaning backup roll 46, and a second cleaning backup roll 48. A cleaning brush 60 disposed so as to be in pressure contact with the surface of the stretched intermediate transfer belt 20, and residual toner and paper dust removed by the scraper 58 and the cleaning brush 60 are contained in the cleaning device 44. It has come to be collected.

  The cleaning device 44 is disposed so as to be able to swing counterclockwise in the drawing with the swing shaft 62 as the center, and until the secondary transfer of the final color toner image is completed, the intermediate transfer belt is provided. It is configured to retreat to a position separated from the surface of the surface 20 and to contact the surface of the intermediate transfer belt 20 when the secondary transfer of the final color toner image is completed.

  Further, the recording paper 24 onto which the toner image is transferred from the intermediate transfer belt 20 is conveyed to a fixing device 64, and the fixing device 64 fixes the toner image on the recording paper 24 with heat and pressure. In this case, the paper is discharged as it is onto a discharge tray 68 provided at the top of the printer 10 by a discharge roll 66.

  On the other hand, in the case of double-sided printing, the recording paper 24 on which the toner image is fixed by the fixing device 64 is not directly discharged onto the discharge tray 68 by the discharge roll 66, but the rear end of the recording paper 24 by the discharge roll 66. The paper discharge path 66 is reversed in a state where the section is held, and the conveyance path of the recording paper 24 is switched to the double-sided paper conveyance path 70, and the conveyance roll 72 disposed in the double-sided paper conveyance path 70 Then, the recording paper 24 is conveyed again to the secondary transfer position of the intermediate transfer belt 20 with the front and back sides of the recording paper 24 reversed, and an image is formed on the back surface of the recording paper 24.

  Further, in the full color printer, a manual feed tray 74 can be attached to the side surface of the printer 10 so as to be freely opened and closed as an option. An arbitrary size and type of recording paper 24 placed on the manual feed tray 74 is fed by a paper feed roll 76, and the secondary transfer position of the intermediate transfer belt 20 via a transport roll 72 and a registration roll 36. Thus, it is possible to form an image on the recording paper 24 of any size and type.

  The surface of the photosensitive drum 12 after the toner image transfer process is completed is cleaned by the cleaning blade 80 of the cleaning device 78 disposed obliquely below the photosensitive drum 12 every time the photosensitive drum 12 rotates once. Residual toner is removed to prepare for the next image forming process.

  On the other hand, FIG. 3 and FIG. 4 show a rotary developing device 18. FIG. 3 shows a state where one developing device 18Y and developer cartridge 82Y are mounted on the developing device 18 for convenience.

  The developing device 18 includes a rotary 39 that supports the developing devices 18Y, M, C, and K. The rotary 39 is provided with a cylindrical rotary shaft member 41. The rotary 39 is pivotally supported around the rotary shaft member 41 so as to be able to rotate counterclockwise (in the direction of arrow A). Further, a front flange member 43 is provided at the front end of the rotary shaft member 41 in the longitudinal direction, and a rear side is provided at the rear end of the rotary shaft member 41 in the longitudinal direction of the drawing. The flange member 45 is provided.

  As shown in FIG. 19, a rib 43A for home position detection is formed on the rear flange member 45, and a home position sensor 67, which is a transmission type sensor, is formed on the rib 43A on the rear side of the printer 10. Are arranged so as to block the optical axis. As shown in FIG. 4, the home position sensor 67 and the rib 43A are arranged such that the rib 43A is detected by the home position sensor 67 after the developing device 18Y is retracted from the developing position.

  The cylindrical space S formed by the rotary shaft member 41 and the flange members 43 and 45 is divided into four every 90 degrees by the partition member 47.

  In the space partitioned by the partition member 47, four developing devices 18Y, 18M, 18C, and 18K of yellow (Y), magenta (M), cyan (C), and black (K) are clockwise in the circumferential direction. Each is implemented along.

  These developing units 18Y, 18M, 18C and 18K correspond to the developing units 18Y, 18M, 18C and 18K, and develop yellow (Y), magenta (M), cyan (C) and black (K). The developer cartridges 82Y, 82M, 82C, and 82K are mounted, respectively, and a new developer is supplied from the corresponding developer cartridges 82Y, 82M, 82C, and 82K (see FIGS. 5 and 6).

  Here, the developing devices 18Y, 18M, 18C, and 18K and the developer cartridges 82Y, 82M, 82C, and 82K are all configured in the same manner. Therefore, here, the yellow (Y) developing device 18Y and the developer cartridge 82Y. Will be described as an example.

  As shown in FIGS. 8 and 9, the housing 150 of the developing device 18 </ b> Y has a long box shape along the direction orthogonal to the recording sheet to be conveyed, and is substantially in the center in the width direction of the housing 150. The partition wall 152 is erected to partition the housing 150 into a space 154 and a space 156. Clearances 158 and 160 are provided between both ends of the partition wall 152 and the peripheral wall of the housing 150, and the space 154 and the space 156 communicate with each other.

  A spiral auger 90 is disposed in the space 154 along the longitudinal direction of the housing 150, and a spiral auger 92 is disposed in the space 156 in parallel with the spiral auger 90. The spiral augers 90 and 92 include a rotation shaft 162 and are rotatably supported on the peripheral wall of the housing 150.

  As shown in FIGS. 15 and 16, gears 166 and 168 are fixed to the ends of the rotating shaft 162, respectively. A gear 169 meshes with the gear 168, and a gear 89 attached to the rotating shaft of the developing roll 88 and a large-diameter gear 91 </ b> A of the two-stage gear 91 are meshed with the gear 169. A gear 55 attached to the rotating shaft of the agitator 53 rotatably provided in the developer cartridge 82Y is engaged with the small-diameter gear 91B of the two-stage gear 91.

  Here, the developing device 18 is not provided with a drive source, and the spiral augers 90 and 92, the developing roll 88, the agitator 53, and the like of the developing device 18Y include a motor 49 provided in the vicinity of the photosensitive drum 12. It rotates with the rotational force from the gear train 57.

  The gear train 57 includes a motor 49, and a two-stage gear 51 in which a large-diameter gear 51A meshing with the gear 49A of the motor 49 and a small-diameter gear 51B are integrally formed. A gear 169 rotatably supported on the developing device 18Y side meshes with the small-diameter gear 51B of the two-stage gear 51.

  The gear train 57 includes a two-stage gear 59 in which a large-diameter gear 59A meshing with the gear 49A of the motor 49 and a small-diameter gear 59B are integrally formed, and an electromagnetic meshing with the small-diameter gear 59B of the two-stage gear 59. A clutch 61 and a gear 63 meshing with the electromagnetic clutch 61 are provided. A gear 195 attached to a rotating shaft 194 of a spiral auger 94 described later meshes with the gear 63.

  Further, as shown in FIGS. 8 and 9, forward spiral blades 164 formed in a spiral shape are provided around the rotation shaft 162 of the spiral augers 90 and 92 (described later), and a motor 49 (see FIG. 8). 15) is transmitted to the gears 166 and 168, and when the spiral augers 90 and 92 are rotated through the gears 166 and 168, respectively, the developer accommodated in the housing 150 is stirred by the forward spiral blade 164. While being conveyed in the direction of the arrow.

  Further, on the end of the spiral augers 90 and 92 on the downstream side in the conveyance direction, there are provided one or two spiral reverse spiral blades 188 directed in the direction opposite to the spiral direction of the forward spiral blade 164. The developer conveyed by the spiral blade 164 is pushed back in the reverse direction.

  The ends of the spiral augers 90 and 92 pass through the peripheral wall of the developing device 18Y, and the space between the rotating shaft 162 and the peripheral wall of the developing device 18Y is sealed by packing so that the developer in the housing 150 does not leak. However, if the developer conveying force is large, the developer in the developing device 18Y may leak to the outside.

  For this reason, a reverse spiral blade 188 is provided on the downstream side in the transport direction of the spiral augers 90 and 92 to push back the transported developer, so that the transport force of the developer at the ends of the spiral augers 90 and 92 is reduced. In order to prevent the developer from leaking outside.

  On the other hand, a developing roll 88 is disposed obliquely above the spiral auger 92 along the longitudinal direction of the housing 150, and is rotatably supported on the peripheral wall of the housing 150. A gear 89 is fixed to the end portion of the developing roll 88, and the rotational force from the motor 49 (see FIG. 15) is transmitted to the gear 89 and the developing roll 88 rotates through the gear 89.

  At this time, the developer conveyed to the space 156 by the spiral auger 90 through the gap 160 is conveyed in the space 156 in the direction of the arrow by the spiral auger 92 and is equally supplied to the developing roll 88. The layer thickness of the developer supplied to the surface of the developing roll 88 is regulated by a layer thickness regulating member 96 (see FIG. 4).

  Incidentally, the housing 150 is provided with a cover 170, and the cover 170 covers the space 154 and the upper part of the space 156. In this state, as shown in FIG. 4, a part of the developing roll 88 is exposed and can face the photosensitive drum 12.

  The developing roll 88 adsorbs the carrier contained in the developer with a magnetic force, forms a magnetic brush of the developer on the surface, and conveys the toner adsorbed on the carrier to a developing area facing the photosensitive drum 12. Then, the electrostatic latent image formed on the photosensitive drum 12 is visualized by a developer magnetic brush made of a carrier and toner formed on the surface of the developing roll 88.

  In this embodiment, a two-component developer composed of a toner and a carrier is used as the developer. However, as the developer, it is sufficient that the developer contains at least a toner. Of course, it is also possible to use the developer.

  As shown in FIGS. 6 and 7, an arc receiving plate 172 curved in a substantially arc shape is provided on the outer surface of one end side of the cover 170. In the arc receiving plate 172, a supply port 174 for supplying developer in the developer cartridge 82Y, which will be described later, to the housing 150 and excess developer exceeding a predetermined amount in the housing 150 are discharged into the developer cartridge 82Y. A discharge port 176 is formed.

  Further, the arc receiving plate 172 is provided with a shutter plate 114 so as to be slidable along the circumferential direction of the arc receiving plate 172. The shutter plate 114 is formed with a communication port 178 capable of communicating with the discharge port 176, The developer in the housing 150 communicates with the discharge port 176 and is discharged into the developer cartridge 82Y.

  Here, in the shutter plate 114, the communication port 178 and the discharge port 176 are in communication with each other, the developer port 174 is opened in a state where the developer in the housing 150 can be discharged into the developer cartridge 82Y, and the housing 150 It is possible to supply new developer inside.

  On the other hand, as shown in FIGS. 8 and 9, a transport path 180 is provided on the outer surface of the cover 170, and an external supply port 181 communicating with the supply port 174 is provided at one end of the transport path 180. The other end of the conveyance path 180 is provided with an internal supply port 182 communicating with the upstream side of the spiral auger 90 in the conveyance direction.

  A spiral auger 94 having a smaller diameter than the spiral augers 90 and 92 is rotatably supported in the transport path 180, and a gear 195 is fixed to the end of the rotating shaft 194 of the spiral auger 94. . In addition, a forward spiral blade 192 formed in a spiral shape is provided around the rotation shaft 194. When the rotational force is transmitted to the gear 195 and the spiral auger 94 rotates via the gear 195, the replenishing port 174 and the outside are provided. The developer replenished into the conveyance path 180 through the supply port 181 is conveyed to the internal supply port 182 by the forward spiral blade 192 and supplied into the housing 150.

  On the other hand, as shown in FIGS. 4, 6 and 10, the developer cartridge 82Y is constituted by a long cylindrical body having a non-circular cross section. A partition cap 106 is provided inside the developer cartridge 82Y, and is divided into a developer storage portion 102 that stores new developer and a developer recovery portion 104 that recovers excess developer. ing.

  A supply port 108 for supplying a new developer into the housing 150 is provided at the end of the developer accommodating portion 102 and can communicate with a supply port 174 provided on the outer surface of the housing 150. . On the other hand, the developer recovery section 104 is provided with a recovery port 184 for recovering the developer discharged from the housing 150, and the communication port 178 (see FIG. 7) formed in the shutter plate 114 is an arc. The recovery port 184 can communicate with the communication port 178 and the discharge port 176 in a state where it communicates with the discharge port 176 formed in the receiving plate 172.

  Here, as shown in FIG. 8, a nozzle 186 projects from the peripheral edge of the discharge port 176 into the housing 150, and the developer in the housing 150 is guided to the discharge port 176 through the nozzle 186. The

  As shown in FIG. 18A, when the developing unit 18Y is located at the developing position (position B in FIG. 4) where the developing roll 88 faces the photosensitive drum 12, the nozzle 186 faces obliquely downward. The angle is set. For this reason, when the developing device 18Y is located at the developing position, the developer in the housing 150 is not collected by the developer collecting unit 104.

  Then, as shown in FIG. 18B, when the developing device 18Y moves 90 ° from the developing position, the angle of the nozzle 186 is set to face obliquely upward. The inclination angle of the nozzle 186 is set to be steeper than the inclination angle of the developer in the housing 150. Therefore, as shown in FIG. 18C, when the amount of developer contained in the housing 150 increases, the rotation of the rotary 39 causes the developing device 18Y to move counterclockwise by about 90 ° from the developing position. In addition, the developer at a position higher than the height of the front end surface of the nozzle 186 is discharged through the nozzle 186 to the developer collection unit 104 through the discharge port 176, the communication port 178 and the collection port 184.

  This is a so-called trickle system, and the developer charging performance is gradually reduced to prevent the deterioration of the charging performance of the developer and the developer replacement interval is extended. This is a system in which development is carried out while discharging the developer (which contains many deteriorated carriers) from the inside of the developing device.

  Incidentally, as shown in FIGS. 6 and 10, on the outer periphery (partly including the developer accommodating portion 102) of the developer collecting portion 104 formed in the cylindrical shape of the developer cartridge 82Y, the developer accommodating portion 102 is provided. A shutter member 128 that opens and closes the supply port 108 and the recovery port 184 of the developer recovery unit 104 is inserted in a rotatable manner along the circumferential direction.

  As shown in FIGS. 10 and 11, the shutter member 128 has a supply opening 130 and a collection opening 132 at positions corresponding to the supply port 108 and the collection port 184 of the developer cartridge 82Y, respectively. The supply port 108 and the recovery port 184 of the developer cartridge 82Y can be opened and closed simultaneously by rotating the shutter member 128 along the outer periphery of the developer recovery unit 104 of the developer cartridge 82Y. It has become.

  Further, the shutter member 128 is configured to rotate the shutter member 128 to a part in the circumferential direction of the shutter member 128 and to hold the shutter member 128 and attach the developer cartridge 82Y to the developing device 18Y. The handle 134 protrudes outward in the radial direction.

  In the handle 134, when the developer cartridge 82Y is mounted on the developing device 18Y and the supply port 108 and the recovery port 184 are opened, the top portion 134A coincides with the corner portion 83 of the developer cartridge 82Y (A in FIG. 4). In the state in which the supply port 108 and the recovery port 184 are closed, the top portion 134A and the corner portion 83 are arranged in a shifted state, and the handle 134 protrudes from the outer periphery of the developing device 18.

  Further, as shown in FIG. 11, in a state where the developer cartridge 82Y is removed from the developing device 18Y, the movement of the shutter member 128 is restricted so that the supply port 108 and the recovery port 184 of the developer cartridge 82Y are not accidentally opened. It has become. Further, as shown in FIG. 5, when the developer cartridge 82Y is mounted at a predetermined position of the developing device 18Y and the supply port 108 and the recovery port 184 of the developer cartridge 82Y are opened, the developer cartridge 82Y is It cannot be removed from the developing unit 18Y.

  In this embodiment, when the developer cartridge 82Y is mounted in a predetermined position of the developing device 18Y, the developer cartridge 82Y is rotated from the outside in the radial direction of the developing device 18 shown in FIG. By sliding along the housing 150 of the developing device 18Y toward the shaft member 41, the developer cartridge 82Y can be easily attached to and detached from the developing device 18Y.

  Further, when the developer cartridge 82Y is replaced with a new one, as shown in FIG. 2, the developing device 18 is stopped so that the developer cartridge 82Y to be replaced is disposed at the replacement position B, and the printer 10 The side cover 97 provided on the side surface is opened, and the developer cartridge 82Y to be replaced is taken out.

  Here, as shown in FIG. 6, when the developer cartridge 82Y is removed from the developing device 18Y, the handle 134 of the shutter member 128 is rotated by hand, and the shutter member 128 is rotated clockwise. As the shutter member 128 rotates, the supply port 108 and the recovery port 184 of the developer cartridge 82Y are closed.

  Then, with the handle 134 of the shutter member 128 stopped moving, the supply port 108 and the collection port 184 of the developer cartridge 82Y are completely closed. In this state, the developer cartridge 82Y can be detached from the developing device 18Y.

  Next, the main part of the developing device according to the embodiment of the present invention will be described.

  As shown in FIGS. 9 and 12, the developing unit 18Y (note that the developing units 18Y, 18M, 18C, and 18K are all configured in the same manner, and here, the yellow (Y) developing unit 18Y is taken as an example. The spiral auger 90 disposed in the inside is provided with a forward spiral blade 164 formed in a spiral shape around the rotation shaft 162, and the forward spiral blade 164 is provided in the spiral auger 90. The spiral is shaped in the direction of the arrow (forward direction) by rotation. With this spiral shape, the developer in the space 154 is conveyed in the direction of the arrow while being stirred.

  On the other hand, as shown in FIG. 4, a nozzle 186 protrudes into the housing 150 from the peripheral edge of the discharge port 176 formed in the cover 170 of the developing device 18 </ b> Y, and the developer accommodated in the housing 150. When the developing device 18Y is moved to the position B in FIG. 4 by the rotation of the developing device 18, the developer at a position higher than the height of the tip end surface of the nozzle 186 passes through the nozzle 186 and the discharge port 176. The developer is discharged to the developer collecting unit 104 through the communication port 178 and the collecting port 184.

  Here, as shown in FIGS. 9, 13, and 14, the spiral directions of the forward spiral blades 164 of the spirals 90 and 92 are the same. Therefore, as shown in FIG. 9, in order to circulate the developer in the developing device 18Y in the direction of the arrow A, the spiral augers 90 and 92 need only be rotated in the reverse direction (the direction of the arrow B in the figure). As shown in FIGS. 15 and 16, gears 166 and 168 attached to the rotary shafts 162 of the spiral augers 90 and 92 may be directly meshed with each other. That is, it is not necessary to interpose an idle gear in the gear train 165 for rotating the spiral augers 90 and 92, and the gear train 165 can be simplified, so that the developing device 18Y can be reduced in size and the cost can be reduced.

  Since the spiral augers 90 and 92 have the same spiral direction, when the rotary 39 rotates in the counterclockwise direction shown in FIG. 4 (in the direction of arrow A in the figure), the spaces 154 and 156 as shown in FIG. The developer inside is fed in the same direction (in the direction of arrow B in the figure) by the spiral augers 90 and 92 and biased to one side.

  This is because when the developing unit 18Y turns around the rotary shaft member 41 by the rotation of the rotary 39, the rotational positions of the spiral augers 90 and 92 change in the same direction, and the spiral augers 90 and 92 rotate in the same direction. It will be the same thing. Further, as described above, the developing unit 18Y does not have a drive source for driving the spiral augers 90 and 92, and therefore the spiral augers 90 and 92 cannot be rotated during the rotation of the rotary 39.

  For this reason, the nozzle 186 is provided at the end opposite to the side where the developer in the developing unit 18Y is biased so that the developer in the developing unit 18Y is not excessively collected.

  Here, since the spiral augers 90 and 92 are configured so that the developer in the housing 150 is biased in the direction of arrow B during the rotation of the rotary 39, the development is performed as it is, and the developer is uniformly supplied to the entire developing roll 88. This is not possible, and white spots in the image and density unevenness occur. For this reason, the main control unit 100 (see FIG. 17) of the printer 10 performs a uniform operation for eliminating the bias of the developer in the housing 150 between jobs.

  Hereinafter, a first embodiment of the equalizing operation will be described with reference to the flowchart of FIG. In this flow, the developing order is the developing unit 18K, the developing unit 18C, the developing unit 18M, and the developing unit 18Y, but this order can be changed as appropriate.

  First, when the job is started, this flow is started and the process proceeds to Step 1. In step 1, negative determination is repeated until the job is completed. In step 2, until the detection signal is received from the home position sensor 67, that is, as shown in FIG. 21A, development of yellow (Y) of the fourth color is performed, and the developing units 18K to Y are moved to the home position. The negative determination is repeated until the process returns to step S3.

  In step 3, a motor 65 (see FIG. 17) for rotating the rotary 39 is driven by a predetermined rotation from the home position to develop the developing device 18K that develops the first color as shown in FIG. 21B. Move to position. At this time, in the developing device 18Y rotated about 90 ° from the developing position, excess developer in the housing 150 flows into the nozzle 186 and is collected by the developer collecting unit 104. Then, the process proceeds to Step 4.

  In step 4, the motor 49 for rotating the spiral augers 90 and 92 is driven to rotate the spiral augers 90 and 92 of the developing device 18K for about 2 seconds without performing development. As a result, as shown in FIG. 9, the developer circulates in the housing 150, and the developer that is biased to the opposite side of the nozzle 186 spreads throughout the housing 150, and the amount of developer becomes uniform. Then, the process proceeds to Step 5.

  In step 5, the motor 65 is driven by a predetermined rotation, and as shown in FIG. 21C, the developing device 18C for developing the second color is moved to the developing position. At this time, in the developing device 18K rotated by about 90 ° from the developing position, excess developer in the housing 150 flows into the nozzle 186 and is collected by the developer collecting unit 104. Then, the process proceeds to step 6 where the motor 49 is driven as in step 4 to equalize the amount of developer in the housing 150 of the developing unit 18C.

  In step 7, similarly to steps 3 and 5, the motor 65 is driven by a predetermined rotation, and the developing device 18M for developing the third color is moved to the developing position as shown in FIG. At this time, in the developing device 18C rotated by about 90 ° from the developing position, excess developer in the housing 150 flows into the nozzle 186 and is collected by the developer collecting unit 104. In step 8, the motor 49 is driven in the same manner as in steps 4 and 6, and the developer amount in the housing 150 of the developing unit 18C is made uniform.

  In step 9, as in steps 3, 5, and 7, the motor 65 is driven by a predetermined rotation to move the developing unit 18Y that performs the fourth color development to the development position. At this time, in the developing device 18M rotated by about 90 ° from the developing position, excess developer in the housing 150 flows into the nozzle 186 and is collected by the developer collecting unit 104. Then, the process proceeds to step 10, and similarly to steps 4, 6, and 8, the motor 49 is driven to equalize the amount of developer in the housing 150 of the developing device 18Y.

  In step 11, negative determination is repeated until a detection signal is received from the home position sensor 67.

  Next, a second embodiment of the uniformizing operation will be described with reference to the flowchart of FIG.

  First, when the job is started, this flow is started and the process proceeds to step 101. In step 101, it is determined whether or not the job is a black (K) monochrome job. If the determination is affirmative, the process proceeds to step 102. Here, during the black (K) monochromatic job, the three developing devices 18C, 18M, and 18Y other than the developing device 18K are swung around the rotation axis of the rotary 39 without rotating the spiral augers 90 and 92. For this reason, after the black (K) monochrome job is completed, the developer in the housing 150 of the developing units 18C, 18M, and 18Y is biased in one direction. Therefore, an operation is performed to equalize the amount of developer in the housing 150 of the developing units 18C, 18M, and 18Y.

  First, in step 102, the negative determination is repeated until the job is completed. In step 103, as shown in FIG. 23B, the motor 65 is rotated by a predetermined rotation to move the developing unit 18C to the developing position. Here, the developer amount in the developing unit 18K is sufficiently uniformed by the rotation of the spiral augers 90 and 92 during the job, and no uniformizing operation is required, so that the developing position is passed. Then, the motor 49 is rotated for about 2 seconds to rotate the spiral augers 90 and 92 of the developing unit 18C. As a result, the developer biased to the opposite side of the nozzle 186 in the housing 150 of the developing device 18C is sent to the nozzle 186 side, and the amount of developer in the housing 150 becomes uniform. Then, the process proceeds to Step 105.

  In step 105, as in steps 7 and 8 of the first embodiment described above, the developer amount in the housing 150 of the developing unit 18M is equalized as shown in FIG. 23C. In step 106, Similar to Steps 9 and 10 of the first embodiment described above, the developer amount in the housing 150 of the developing device 18Y is equalized. Then, this flow ends.

  Next, a third embodiment of the uniforming operation will be described with reference to the flowchart of FIG.

  First, when the job is started, this flow is started and the process proceeds to step 201. In step 201, for each of the developing devices 18K to Y, the time when the developer is supplied from the developer cartridge 82 to the developing devices 18K to Y, that is, the electromagnetic clutch 61 for turning on / off the rotation of the spiral auger 94 is Accumulate the time that was activated while driving. In step 202, the rotation time of the rotary 39, that is, the drive time of the motor 65 that rotates the rotary 39 is accumulated. Then, the process proceeds to Step 203.

  In step 203, the additional rotational speed of the rotary 39 is calculated from the ratio between the developer supply time accumulated in steps 201 and 202 and the rotational speed of the rotary 39. That is, if the developer supply time is long and the rotation speed of the rotary 39 is small, the developer supply amount increases in each developer 18 and the developer recovery amount decreases, so the developer amount in the housing 150 is Become surplus. Therefore, trickle collection is forcibly performed for each of the developing devices 18K to 18Y after the job is completed.

  In step 204, the negative determination is repeated until the job is completed. In step 205, it is determined whether or not the additional rotational speed of the rotary 39 calculated in step 203 is equal to or higher than the reference rotational speed. If the result is affirmative, the process proceeds to step 206. If the result is negative, the present process is terminated.

  In step 206, the motor 65 is driven by a predetermined rotation, and as shown in FIG. 25 (A), for example, the developing device 18M whose additional rotation speed is equal to or higher than the reference rotation speed is moved to the development position, and the motor 49 is driven. The spiral augers 90 and 92 are rotated. As a result, the developer biased to the opposite side of the nozzle 186 in the housing 150 of the developing device 18M moves to the nozzle 186 side. Then, as shown in FIG. 25B, the developing unit 18M is rotated by about 90 ° from the developing position, and excess developer is poured into the nozzle 186 and is collected by the developer collecting unit 104.

  Here, the rotary 39 is rotated by an additional number of revolutions to collect excess developer in the housing 150 of the developing unit 18M, but the rotation of the rotary 39 is performed without doing the other three developing units 18C, 18Y, and 18K. The developer in the housing 150 of the developer 18 will be biased if the additional rotation speed is swung around the axis. For this reason, as shown in FIGS. 25 (B), (C), and (D), for the developing devices 18 other than the developing device 18M that forcibly collects trickle, as shown in FIGS. The developer is not biased in the housing 150.

  Then, this flow ends.

1 is a configuration diagram of an image forming apparatus according to an embodiment of the present invention. 1 is a configuration diagram of an image forming apparatus according to an embodiment of the present invention, showing a state where an image forming unit is removed. FIG. 1 is a perspective view showing a rotary developing device constituting an image forming apparatus according to an embodiment of the present invention. 1 is a cross-sectional view showing a rotary developing device constituting an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a perspective view showing a developing device and a developer cartridge of the developing device according to the embodiment of the present invention. FIG. 2 is an exploded perspective view showing a developing device and a developer cartridge of the developing device according to the embodiment of the present invention. It is a perspective view which shows the developing device of the developing device which concerns on embodiment of this invention. FIG. 3 is an exploded perspective view showing a housing and a cover of a developing device of the developing device according to the embodiment of the present invention. FIG. 4 is a plan view of the housing side of the developing device of the developing device according to the embodiment of the present invention. FIG. 4 is a cross-sectional view of a developer cartridge mounted on a developing device of a developing device according to an embodiment of the present invention. FIG. 4 is a perspective view of a developer cartridge mounted on a developing device of a developing device according to an embodiment of the present invention. It is a perspective view of the spiral auger in the developing device of the developing device according to the embodiment of the present invention. FIG. 4 is a perspective view of the housing side of the developing device of the developing device according to the embodiment of the present invention. FIG. 4 is a plan view of the housing side of the developing device of the developing device according to the embodiment of the present invention. It is a top view which shows the gear train of the developing device which concerns on embodiment of this invention. It is a side view which shows the gear train of the developing device which concerns on embodiment of this invention. 1 is a block diagram illustrating an outline of an image forming apparatus according to an embodiment of the present invention. FIGS. 4A to 4C are cross-sectional views illustrating a developing device and a developer cartridge of a developing device according to an embodiment of the present invention. It is a perspective view which shows the rotary of the developing device which concerns on embodiment of this invention. 6 is a flowchart for explaining a first example of a uniformizing operation in the developing device according to the embodiment of the present invention; (A)-(D) are sectional drawings which show the developing device which concerns on embodiment of this invention. It is a flowchart for demonstrating the 2nd Example of the equalization operation | movement in the image development apparatus concerning embodiment of this invention. (A)-(D) are sectional drawings which show the developing device which concerns on embodiment of this invention. It is a flowchart for demonstrating the 3rd Example of the equalization operation | movement in the image development apparatus concerning embodiment of this invention. (A)-(D) are sectional drawings which show the developing device which concerns on embodiment of this invention.

Explanation of symbols

12 Photosensitive drum (image carrier)
18 Developing Device 18C Developing Device 18M Developing Device 18Y Developing Device 18K Developing Device 39 Rotary (Rotating Body)
49 Motor (stirring member driving means)
65 Motor (rotating body drive means)
67 Home position sensor 88 Developing roll 90 Spiral auger (stirring member)
92 Spiral auger (stirring member)
100 Main control unit (control means)
104 Developer collection unit (collection unit)
162 Rotating shaft 164 Agitation blade 186 Nozzle (recovery port)

Claims (6)

A plurality of agitating members having spiral agitating blades formed on the rotating shaft circulate while agitating the developer along the developing roll, and the developing roll is carrying an image with the developer agitated by the agitating member. A plurality of developing units for developing the body;
A plurality of recovery units for recovering excess developer in the developer unit from a recovery port facing the developer circulation path in the developer unit;
By supporting and rotating the plurality of developing units and the plurality of collecting units, each developing unit is sequentially opposed to the image carrier, and excessive developer in each developing unit is sequentially collected to the collecting unit. A rotating body,
Rotator driving means for rotating the rotator in one direction;
Agitating member driving means for rotating a plurality of the agitating members of each developing device rotated to a developing position facing the image carrier;
A developing device comprising:
The stirrer blades of the plurality of stirrers have the same swirling direction, and the swirl direction is fed in a direction in which the developer in the developing unit is separated from the recovery port by the rotational force of the rotating body in the one direction. Configured to
A developing apparatus comprising a control means for driving the rotating member driving means to move each developing device to the developing position and driving the stirring member driving means between jobs. A home position sensor for detecting a home position of the rotating body;
The control means, when receiving a detection signal from the home position sensor, drives the rotating body driving means, moves each developing device to the developing position, and drives the stirring member driving means. 2. The developing device according to 1.   2. The developing device according to claim 1, wherein the control unit drives the rotating body driving unit to move each developing unit to the developing position and drives the stirring member driving unit after the monochrome job is finished. .   The control means drives the rotating body driving means in the recovery mode for recovering excess developer in a predetermined developing device, and moves the developing device to the developing position to drive the stirring member driving means. The developing device according to claim 1, wherein each developing device other than the developing device is moved to the developing position to drive the stirring member driving unit.   5. The control unit according to claim 1, wherein when the developing device is rotated to the developing position, the rotating member driving unit is temporarily stopped to drive the stirring member driving unit. 6. The developing device according to 1.   6. The recovery port is provided at an upstream end in a direction in which developer in the developing device is fed by the stirring member when the rotating body rotates in the one direction. The developing device according to any one of the above.

Images