JP4483399B2 - Developing device, rotary developing device, and image forming apparatus - Google Patents

Description

  The present invention relates to a developing device, a rotary developing device, and an image forming apparatus that are used in an image forming apparatus such as a copying machine, a printer, a facsimile, or a composite machine using an electrophotographic system.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copying machines, printers, facsimiles, or composite machines using an electrophotographic method are equipped with a developing device filled with a developer (consisting of toner and a magnetic carrier). An image is formed by disposing the apparatus opposite to the photosensitive member, causing the toner to fly on the surface of the photosensitive member, and making the electrostatic latent image visible with the toner.

  Here, in the developing device, a magnet roll and two spiral augers are rotatably supported by a housing, and the two spiral augers are rotatable in the reverse direction. In addition, a partition wall is formed in the housing along the longitudinal direction of the housing, the inside of the housing is partitioned into two spaces, and a spiral auger is disposed in each of these spaces.

  Further, the housing is provided with a transfer port for transferring the developer, and the two spaces communicate with each other. A developer inlet to which developer is supplied is provided in one space, and the developer supplied from the developer inlet is conveyed by one spiral auger and guided to the other space through a transfer port. The The developer is conveyed by the other spiral auger, and the developer toner is supplied to the magnet roll.

  By the way, in patent documents 1 and 2, the transfer port is provided in the central part of the housing, and the direction of the spiral is mutually changed by the left and right in the axial direction of the first spiral auger (the first spiral blade and the second spiral blade). On the contrary, in the central portion, the first spiral blade and the second spiral blade have a phase angle of 180 degrees with respect to each other and do not intersect with each other. The developer conveyed by the spiral blade is mixed at a substantially equal ratio.

However, these developing devices are not configured to discharge the developer to the outside, and do not consider the amount of developer discharged.
Japanese Patent Laid-Open No. 7-333995 JP-A-8-6396

  In view of the above facts, an object of the present invention is to provide a developing device, a rotary developing device, and an image forming apparatus in which the discharge amount is regulated according to the amount of developer.

According to the first aspect of the present invention, in the developing device, a supply member that is housed in the housing and supplies the developer to the developer carrying member, and is disposed in parallel with the supply member in the housing, to the supply member side. A conveying member that conveys the developer while stirring; and a discharge port that is provided at an end in the longitudinal direction of the housing and discharges the developer, and faces an image carrier on which an electrostatic latent image is formed. a rotary developing device developing device for forming an image to form a rotating image, wherein the conveying member is towards the rotary shaft, the developer around the rotation axis in the direction of conveying to the outlet reverse spiral vane for regulating the forward spiral vanes formed in a spiral shape, a pre SL are formed in a spiral shape around the rotation axis toward the forward spiral blades and reverse developer supply port to said exhaust port Te And in Made, provided on the conveying member, and the forward spiral blades and any free area of the reverse spiral blade, is disposed near the region, and projects from the outlet into the housing, the developer A nozzle that discharges to the developer recovery unit, and at a standby position where an image is formed next, the developer at a position where the tip of the nozzle faces a level above the horizontal plane and is higher than the tip of the nozzle It is characterized by being discharged .

The invention according to claim 1, a rotary developing device developing device for forming an image faces the image bearing member to form an image by rotating the developer to the developer carrying member in the housing A supply member that supplies the developer and a conveyance member that conveys the developer to the supply member side while stirring are accommodated in parallel to each other. Further, a discharge port for discharging the developer is provided at an end portion in the longitudinal direction of the housing.

  On the other hand, the conveying member is provided with a rotating shaft, and forward spiral blades formed in a spiral shape are provided around the rotating shaft in the direction of conveying the developer to the discharge port. Further, a reverse spiral blade is provided in the vicinity of the discharge port of the conveying member so as to spiral in the direction opposite to the forward spiral blade centering on the rotation axis, and regulates the developer supplied to the discharge port. A region where neither the reverse spiral blade nor the forward spiral blade is present is provided.

  In the forward spiral blade and the reverse spiral blade of the conveying member, the forward spiral blade has a longer length along the axial direction of the rotation shaft. For this reason, when the forward direction spiral blade and the reverse direction spiral blade are made continuous, the developer conveying force in the forward direction (the direction in which the developer is conveyed to the discharge port) is strong, and the amount of developer in the developing device is large. Regardless of the amount, the developer gets over the reverse spiral blade and reaches the discharge port, and the developer in the developing device always tends to be excessively discharged. (Image loss) is likely to occur.

  Therefore, by providing an area where neither the reverse spiral blade nor the forward spiral blade is provided, the forward spiral blade and the reverse spiral blade are discontinuous.

The transport member is provided with a region in which neither the forward spiral blade nor the reverse spiral blade is provided, and a nozzle is provided in the vicinity of the region. The nozzle projects from the discharge port into the housing, and is developed through the nozzle. The developer is discharged to the developer recovery unit. By providing the nozzle in the vicinity of any open area of the forward spiral blades and reverse spiral blade, it becomes Kiru de reduce the conveying force in the forward direction at the vicinity of the front end portion of the nozzle. Here, in the developing device arranged at the standby position for forming the next image, the tip of the nozzle faces upward from the horizontal plane, and the developer at a position higher than the tip of the nozzle is discharged. Yes. For this reason, an appropriate amount of developer can be discharged according to the amount of developer in the developing device .

In other words, it is possible to change the discharge amount of the deteriorated developer before development in accordance with the change in the developer amount, to prevent the developer from being excessively discharged and to suppress the occurrence of image defects. Thus, the developer amount can be maintained in the developing device , and as a result, a stable print image quality can be maintained over a long period of time.

  According to a second aspect of the present invention, in the developing device according to the first aspect, the number of turns of the reverse spiral blade is 1-2.

  According to the second aspect of the present invention, by setting the number of turns of the reverse spiral blade to be 1-2, the force that pushes back the developer over the reverse spiral blade by the forward spiral blade to the forward spiral blade side is reduced. is doing. As a result, the developer pushed out by the forward spiral blade toward the reverse spiral blade according to the amount of the developer in the developing device can be reliably discharged.

The invention of claim 3 has a rotary body rotating holds a plurality of developing apparatus according to claim 1 or 2, wherein the developing device is opposed to the sequential photosensitive drum by rotation of said rotary member In the rotary developing device for forming a multicolor image, the end of the reverse spiral blade does not reach the end of the rotating shaft.

  According to the third aspect of the present invention, the end of the reverse direction spiral blade does not reach the end of the rotating shaft, so that the end of the rotating shaft of the conveying member is in the state of only the rotating shaft. Therefore, when the rotating body rotates, the developer that accumulates in the vicinity of the rotating shaft is provided in the developing device and is supplied with toner to an image carrier (for example, a photosensitive drum) without being obstructed by the reverse spiral blade. It can drop to the agent carrier (for example, magnet roll) side.

  According to a fourth aspect of the present invention, in the image forming apparatus, the rotary developing device according to the third aspect is provided.

The present invention, since the above structure, in the invention according to claim 1 and 4, can thus receive to reduce the conveying force in the forward direction at the vicinity of the front end portion of the nozzle. For this reason, an appropriate amount of developer can be discharged according to the amount of developer in the developing device . In other words, it is possible to change the discharge amount of the deteriorated developer before development in accordance with the change in the developer amount, to prevent the developer from being excessively discharged and to suppress the occurrence of image defects. Thus, the developer amount can be maintained in the developing device , and as a result, a stable print image quality can be maintained over a long period of time.

  According to the second aspect of the present invention, the force that pushes back the developer that has passed over the reverse spiral blade by the forward spiral blade to the forward spiral blade side is reduced, so that the forward flow is reduced according to the amount of the developer in the developing device. The developer pushed out to the reverse spiral blade side by the direction spiral blade can be reliably discharged.

  According to the third aspect of the present invention, the developer accumulated in the vicinity of the rotating shaft during rotation of the rotating body is provided in the developing device without being obstructed by the reverse spiral blades (for example, a photosensitive drum). The toner can be dropped to a developer carrying body (for example, a magnet roll) that supplies toner.

  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, the 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 is used. 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 is provided with a cylindrical rotating shaft member 41 and is rotatably supported around the rotating shaft member 41 in a counterclockwise direction. 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. A cylindrical space S formed by the rotary shaft member 41 and the flange members 43 and 45 is divided into four spaces every 90 degrees by a 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. Gears 166 and 168 are fixed to end portions of the rotating shaft 162, respectively.

  In addition, forward spiral blades 164 formed in a spiral shape are provided around the rotation shafts 162 of the spiral augers 90 and 92 (described later), and rotational force from a motor (not shown) is transmitted to the gears 166 and 168. When the spiral augers 90 and 92 are rotated through the gears 166 and 168, the forward spiral blade 164 conveys the developer contained in the housing 150 in the direction of the arrow while being stirred.

  Further, on the end side downstream of the spiral augers 90 and 92 in the transport 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, by providing a reverse spiral blade 188 on the downstream side of the spiral augers 90 and 92 in the transport direction so as to push back the transported developer, 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 is transmitted to the gear 89 so that 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. The arc receiving plate 172 is supplied with a supply port 174 for supplying developer in the developer cartridge 82Y, which will be described later, to the housing 150, and used developer (developer exceeding a predetermined amount) in the housing 150 as developer. A discharge port 176 for discharging into the cartridge 82Y 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 smaller in 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 accommodating portion 102 that accommodates a new developer and a developer collecting portion 104 that collects a used developer. Has been.

  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

  That is, as shown in FIG. 4, when the amount of developer accommodated in the housing 150 increases, the developing device 18Y is moved when the developing device 18Y is moved to the position B in FIG. The developer at a position higher than the height of the tip end surface of the nozzle 186 passes through the nozzle 186, the discharge port 176, the communication port 178 and the recovery port 184 shown in FIGS. 6 and 7, and the developer recovery unit 104 (see FIG. 4). Is discharged.

  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 rotatably fitted 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 FIG. 9, the developing unit 18Y (the developing units 18Y, 18M, 18C, and 18K are all configured in the same manner, and therefore, here, the yellow (Y) developing unit 18Y will be described 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 spiraled by the rotation of the spiral auger 90. Is shaped in the direction of the arrow (forward direction). 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. 12A and 12B (note that FIGS. 12A and 12B schematically show the spiral augers 90 and 92), the reverse spiral blade 188 is a nozzle. It is formed in the vicinity of 186. That is, the developer that has overcome the reverse spiral blade 188 is discharged to the developer recovery unit 104.

  As shown in FIG. 12B, the spiral auger 90 is provided with a region 190 in which neither the forward spiral blade 164 nor the reverse spiral blade 188 is present. That is, the forward spiral blade 164 is cut by 1/4 turn on the reverse spiral blade 188 side to make the forward spiral blade 164 and the reverse spiral blade 188 discontinuous.

  In the forward spiral blade 164 and the reverse spiral blade 188 of the spiral auger 90, the forward spiral blade 164 has a longer length along the axial direction of the rotation shaft 162. For this reason, when the forward spiral blade 164 and the reverse spiral blade 188 are made continuous, the developer conveying force in the forward direction becomes strong as shown in FIG.

  Therefore, regardless of the amount of the developer in the developing device 18Y, the developer gets over the reverse spiral blade 188 and reaches the nozzle 186, and the developer in the developing device 18Y always tends to be excessively discharged, and the printing result. As a result, defects such as oblique stripes due to the spiral of the spiral auger 90 are likely to occur.

  For this reason, by providing the spiral auger 90 with a region 190 in which neither the forward spiral blade 164 nor the reverse spiral blade 188 is provided, only the rotating shaft 162 exists between the forward spiral blade 164 and the reverse spiral blade 188. As shown in FIG. 12B, the forward conveying force in the vicinity of the nozzle 186 can be reduced. Thereby, the flow rate of the developer in the vicinity of the nozzle 186 can be intentionally changed with respect to the fluctuation of the developer amount.

  On the other hand, FIGS. 13A and 13B show the relationship between the axial position of the spiral auger 90 and the height of the developer surface, and the solid line is the reference value of the developer amount (Sump amount). is there. According to this, in the present invention, as shown in FIG. 13B, an appropriate amount of developer can be discharged according to the amount of developer in the developing device 18Y.

  That is, it becomes possible to change the discharge amount of the deteriorated developer in accordance with the change in the developer amount. As shown in FIG. 13A, the developer is excessively discharged (regardless of the amount of the developer, The developer discharge amount is always greater than the reference value), and a constant developer amount is always maintained in the developing device 18Y, and as a result, stable print image quality can be maintained over a long period of time. Become.

  Here, as shown in FIG. 9, the end of the forward spiral blade 164 protrudes from the end of the partition wall 152 in a state where the spiral auger 90 is projected onto the partition wall 152. Thereby, the developer conveyed by the spiral auger 90 can be reliably guided to the end portion side of the developing roll 88 through the gap 160.

  If the cut amount of the forward spiral blade 164 is too large, the ability to replace the developer at the end portion of the developing roll 88 is lowered, which causes a decrease in density at the image end portion. Therefore, here, the 1/4 spiral is cut on the reverse spiral blade 188 side of the forward spiral blade 164, but a cut from 1/4 to 3/4 is preferable.

  Further, by setting the number of turns of the reverse spiral blade 188 to 1 to 2, the force that pushes back the developer that has overcome the reverse spiral blade 188 by the forward spiral blade 164 to the forward spiral blade 164 side is reduced.

  In the developing device 18Y, the developer is discharged through the nozzle 186 in a state where the amount of the developer in the developing device 18Y exceeds about 180 g. However, as shown in FIG. 14, when the number of turns of the reverse spiral blade 188 is large, The developer that gets over the reverse spiral blade 188 and is discharged to the developer recovery unit 104 (see FIG. 4) of the developer cartridge 82 is pushed back to the forward spiral blade 164 side, and the developer is removed. It becomes impossible to discharge effectively.

  Therefore, if the number of turns of the reverse spiral blade 188 is 1-2, the developer pushed out to the reverse spiral blade 188 side by the forward spiral blade 164 according to the amount of developer in the developing device 18Y can be effectively used. It can be discharged.

  Further, as shown in FIGS. 8 and 12B, the rotation shaft 162 of the spiral auger 90 is prevented by preventing the end of the reverse spiral blade 188 from reaching the end of the rotation shaft 162 located in the housing 150. Only the rotating shaft 162 is in the state of the end portion. For this reason, when the developing device 18 rotates, the developer collected in the vicinity of the rotating shaft 162 can be dropped to the developing roll 88 side without being obstructed by the reverse spiral blade 188.

  Although the rotary developing device has been described here, it is needless to say that it may be applied to a tandem developing device.

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. 3 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. (B) is a schematic plan view showing the housing side of the developing device of the developing device according to the embodiment of the present invention, and (A) is a comparative view of (B). (B) is a diagram showing the relationship between the axial position of the spiral auger of the developing device of the developing device according to the embodiment of the present invention and the height of the developer surface, and (A) is a comparative view of (B). It is. It is a figure which shows the relationship between the winding number of a reverse spiral blade | wing, and the discharge amount of a developer.

Explanation of symbols

10 Printer (image forming device)
18 Development device (rotary development device)
18Y developing device 18K developing device 18C developing unit 18M developing unit 82 the developer cartridge 82Y developer cartridge 88 developing roller (developer carrying member)
90 Spiral auger (conveying member)
92 Spiral auger (supply member)
162 Rotating shaft (conveying member)
164 Forward spiral blade (forward spiral blade, conveying member)
176 outlet 186 Nozzle <br/> 188 opposite spiral vanes (reverse spiral blade, conveying member)
190 areas

Claims (4)

A supply member that is housed in the housing and supplies the developer to the developer carrying member, and is arranged in parallel with the supply member in the housing and conveys the developer while stirring the developer toward the supply member; and and a discharge port for discharging the developer is provided in the longitudinal end of the housing, an image bearing member on which an electrostatic latent image is formed and opposite to the developing unit for forming an image is rotated form the image A rotary developing device,
The conveying member is
A rotation axis;
A forward spiral blade formed in a spiral shape in the direction of transporting the developer to the discharge port around the rotation axis;
A reverse spiral blade formed in a spiral shape around the front Symbol rotation axis toward the forward spiral blades opposite direction to regulate the developer supplied to the discharge port,
Consists of
An area provided on the conveying member, where neither the forward spiral blade nor the reverse spiral blade is present,
A nozzle that is disposed in the vicinity of the region, protrudes from the discharge port into the housing, and discharges the developer to a developer recovery section;
Have
Next, at a standby position where an image is formed , the developing device is characterized in that the tip of the nozzle faces upward from a horizontal plane and the developer at a position higher than the tip of the nozzle is discharged .   The developing device according to claim 1, wherein the number of turns of the reverse spiral blade is 1-2. 3. A rotary developing device comprising: a rotating body that holds and rotates a plurality of the developing devices according to claim 1; and the developing device sequentially forms a multicolor image by facing the photosensitive drum by the rotation of the rotating body. In the device
The rotary developing device, wherein the end of the reverse spiral blade does not reach the end of the rotating shaft.   An image forming apparatus comprising the rotary developing device according to claim 3.

Images