JP2011149976A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device in which an amount of developer supplied to a rotating developer carrier is regulated by a regulation member to convey the developer to an image carrier, and in which the developer is appropriately supplied at a fixed amount while it is dispersed to the developer carrier. <P>SOLUTION: In the developing device 20 in which the amount of the developer conveyed by the rotating developer carrier 21 is regulated by the regulation member 26 to convey the developer to the image carrier 10, a pair of screw members 25 and 26 provided with spiral screw blades 25b and 26b on outer peripheries of rotary shafts 25a and 26a is disposed along the developer carrier in first and second developer conveying and supplying parts 22 and 23 supplying the developer while conveying it along the developer carrier below the developer carrier, and a partition member 27 where a plurality of supply ports 27a are formed through required intervals in an axial direction of the developer carrier between the developer carrier and each of the screw members. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile machine, and a composite machine thereof, and a developing apparatus for developing by supplying toner to an image carrier in such an image forming apparatus. It is. In particular, the developer carrying member supplied with a developer containing toner and carrier is rotated to convey the developer toward the image carrying member by the developer carrying member, and the development carried by the developer carrying member. In the developing device in which the amount of the developer is regulated by the regulating member, the amount of the developer supplied to the developer carrier so that the developer is dispersed in the developer carrier and appropriately supplied in a constant amount. This is characterized in that an appropriate amount of developer can be stably guided to a development position facing the image carrier without increasing the amount of toner.

  In an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile, and a composite machine thereof, generally, toner is supplied from a developer carrier provided in a developing device to the image carrier, thereby carrying the image. The electrostatic latent image formed on the body is developed.

  As such a developing device, a one-component developing type developing device using only toner as a developer and a two-component developing type developing device using a developer containing toner and a carrier are known. From the viewpoint of quickly and appropriately charging the toner to form a high-speed image, a two-component developing type developing device using a developer containing toner and carrier is excellent.

  Here, as a developing device of a two-component developing system using a developer containing toner and a carrier, for example, as shown in Patent Document 1 and the like, a developer supply transport path provided along a developer carrier A screw member having a spiral screw blade provided on the outer periphery of the rotating shaft is provided inside, and the developer member is rotated while the developer member is being transported by rotating the screw member. I am trying to supply. A screw member provided with spiral screw blades on the outer periphery of the rotation shaft is also provided in the developer circulation conveyance path partitioned by the developer supply conveyance path and the partition wall, and the screw member is rotated. The developer in the developer circulation conveyance path is conveyed in the direction opposite to the developer supply conveyance path, and the developer is developed through the first circulation port and the second circulation port provided at both ends of the partition wall. A toner is used that is circulated between a developer supply conveyance path and a developer circulation conveyance path so that the toner in the developer is charged by contacting the carrier.

  In the developing device, the developer carrying member supplied with the developer by the screw member as described above is rotated so that the developer supplied to the developer carrying member is opposed to the image carrying member. Before the development by guiding to the developer, the developer guided to the development position facing the image carrier by the developer carrier by the regulating member provided so as to face the developer carrier with a necessary interval. The amount is regulated so that the amount of the developer guided to the development position facing the image carrier is made constant.

  Here, as described above, the screw member provided with the spiral screw blades on the outer periphery of the rotating shaft is rotated so that the developer in the developer supply transport path is supplied to the developer carrier. In this case, the amount of the developer supplied to the developer carrying member by the spiral screw blade varies in the axial direction of the developer carrying member, and the developer supplied in the axial direction of the developer carrying member. Pitch unevenness due to the above-described screw blades occurred in the amount.

  When the developer supplied to the developer carrying member is guided to the regulating member in the state where the pitch unevenness occurs in the amount of the developer in the axial direction of the developer carrying member as described above, the developer carrying member faces the image carrying member. It becomes difficult to properly regulate and stabilize the amount of developer guided to the development position by the regulating member, and the amount of developer guided to the development position facing the image carrier by the developer carrier is uneven. As a result, density unevenness may occur in the formed image.

  For this reason, conventionally, the developer supplied to the developer carrying member by the screw member is generally increased, and the developer supplied to the developer carrying member even in a portion where the amount of the developer is small. Is regulated by a regulating member.

  However, when the amount of the developer supplied to the developer carrier by the screw member is increased as described above, a large amount of developer is regulated by the regulating member, and the rotation of the developer carrier or the like As the load applied to the developer increases, the load applied to the developer also increases, causing problems such as deterioration of the developer.

Japanese Patent No. 3916595

  In the present invention, a developer carrying body supplied with a developer containing toner and a carrier is rotated so that the developer carrying body conveys the developer toward the image carrying body and is carried by the developer carrying body. It is an object of the present invention to solve the above-described problems in a developing device in which the amount of developer to be regulated is regulated by a regulating member.

  That is, in the present invention, in the developing device as described above, the developer is dispersed on the developer carrier and appropriately supplied in a constant amount, and the amount of developer supplied to the developer carrier is adjusted. Even if it is not increased, an appropriate amount of developer is stably guided to the development position facing the image carrier to prevent density unevenness in the formed image. It is an object of the present invention to reduce the rotation applied to the developer carrier and the load applied to the developer by regulation.

  In the developing device of the present invention, in order to solve the above-described problems, the developer carrying member supplied with the developer containing toner and carrier is rotated, and the developer carrying member causes the developer to become an image carrying member. In the developing device in which the amount of developer conveyed by the developer carrier is regulated by the regulating member, the developer is placed on the developer carrier below the developer carrier. Provided with a first developer transport supply section and a second developer transport supply section that are supplied to the developer carrier while being transported along the screw carrier, and screw blades spiraled around the outer periphery of the rotating shaft in each developer transport supply section Are provided along the developer carrying member, and a plurality of supply ports are provided between the developer carrying member and each of the above screw members via a predetermined interval in the axial direction of the developer carrying member. Open A partition member is provided, and the developer is transported in the reverse direction between the first developer transport supply unit and the second developer transport supply unit by the screw blades in each screw member, and the developer carrier is passed through the supply port. A developer was supplied.

  Here, in the above developing device, the screw blades in each screw member make the amount of developer supplied to the developer carrier through each supply port provided in the partition member constant. It is preferable that the period of supplying the developer to the developer carrier through the supply port provided in the partition member is shifted, and in particular, the screw in each screw member that supplies the developer to the developer carrier through the supply port. It is preferable that the blade period is shifted by 180 degrees, and that the total amount of each developer supplied to the developer carrier through each supply port by the screw blades in each screw member is constant.

  Further, in order to distribute the developer to the developer carrier through each supply port provided in the partition member by each screw member and to supply the developer appropriately with a constant amount of developer, In addition to the above-described screw blades, it is preferable to provide an auxiliary member for sending developer to each supply port in each screw member so as to correspond to the position of each supply port provided.

  In the image forming apparatus of the present invention, the developer is conveyed to the image carrier by the developer carrier in the developing device as described above, and development is performed.

  In the developing device of the present invention, the first developer transport supply unit and the second developer transport supply unit provided below the developer support along the developer support are respectively spirally formed on the outer periphery of the rotation shaft. Since the screw member provided with the screw blades provided, the developer is transported in the opposite direction by the screw blades in each screw member in the first developer transport supply unit and the second developer transport supply unit, The developer is circulated between the first developer conveyance supply unit and the second developer conveyance supply unit while being appropriately agitated by the screw blades in each screw member so that the toner is sufficiently in contact with the carrier and charged. become.

  Further, in the developing device of the present invention, the developer in the first developer transport supply unit and the second developer transport supply unit is made into the developer carrier by the spiral screw blades provided in each screw member. In supplying, a partition member having a plurality of supply ports opened through a required interval in the axial direction of the developer carrier is provided between the developer carrier and each screw member, and the screw blades in each screw member Since the developer in each developer transport and supply unit is supplied to the developer carrier through each of the supply ports, the developer corresponds to each supply port in the axial direction of the developer carrier. The toner is supplied in a state of being dispersed on the surface of the carrier, and a constant amount of developer is supplied in a state of being appropriately dispersed on the surface of the developer carrier.

  Further, when the developer is supplied to the developer carrying member through the supply port provided in the partition member by the screw blade in each screw member, the developer is supplied to the developer carrying member through the supply port by the screw blade in each screw member. If the period of shifting is shifted, fluctuations in the amount of developer supplied to the developer carrier through each supply port are suppressed. In particular, when the cycle of the screw blades in each screw member that supplies developer to the developer carrier through each supply port is shifted by 180 degrees, the pitch unevenness generated by each screw blade is reversed and cancelled. The amount of the developer dispersed and supplied to the surface of the developer carrier through each supply port by the screw blades in each screw member becomes constant in the developer carrier.

  Further, if an auxiliary member for sending developer to each supply port is provided on each screw member separately from the above-described screw blade so as to correspond to the position of each supply port provided on the partition member, A constant amount of developer is stably supplied to the developer carrying member through the supply port.

  Then, as described above, as a result of supplying a constant amount of developer appropriately dispersed on the surface of the developer carrier, in the developing device of the present invention, the developer carrier to which the developer is supplied , And when the amount of developer conveyed by the developer carrier is regulated by the regulating member and led to the development position facing the image carrier, the amount of developer supplied to the developer carrier is increased. Even if not, unevenness in the amount of the developer guided to the development position facing the image carrier is suppressed, and development is performed when the amount of developer conveyed by the developer carrier is regulated by the regulating member. The load applied to the rotation of the developer carrier and the like is reduced, the load applied to the developer is reduced, and the developer is prevented from deteriorating.

  As a result, in the image forming apparatus of the present invention using the developing device as described above, unevenness in the amount of developer guided to the development position facing the image carrier by the developer carrier is suppressed, The power required for rotation of the developer carrier and the like is reduced, and the developer is prevented from being deteriorated, and good image formation without density unevenness can be stably performed.

1 is a schematic explanatory diagram illustrating a state in which image formation is performed using an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a schematic explanatory view showing a state in which development is performed using the developing device according to an embodiment of the present invention in the image forming apparatus. Each of the first and second developer transport and supply units in the developing device according to the above-described embodiment is provided with a screw member provided with screw blades spiraled on the outer periphery of the rotation shaft, and a plurality of supplies It is schematic sectional drawing which showed the state which provided the partition member by which the opening | mouth was opened. It is the partial schematic plan view which showed the example of a change of the screw member used in the image development apparatus which concerns on said embodiment.

  Next, an image forming apparatus and a developing apparatus according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. Note that the image forming apparatus and the developing apparatus according to the present invention are not limited to those shown in the following embodiments, and can be appropriately modified and implemented without departing from the scope of the invention.

  In the image forming apparatus according to this embodiment, as shown in FIG. 1, four developing devices 20 are provided corresponding to four photosensitive drums (image carriers) 10 and containing developer including toner and carrier. Is provided.

  Each developing device 20 is provided with a developing roller (developer carrying member) 21 that rotates and conveys the developer to the photosensitive drum 10 so as to face the corresponding photosensitive drum 10 and each developing device 20. The apparatus 20 uses black, yellow, magenta, and cyan toners with different toner colors in each developer.

  Then, when full-color image formation is performed by this image forming apparatus, each of the photosensitive drums 10 is rotated, and the surface of each of the photosensitive drums 10 is charged by the charging device 11, respectively. Each of the photosensitive drums 10 is exposed according to the image formation information by the latent image forming device 12 so that an electrostatic latent image is formed on the surface of each of the photosensitive drums 10.

  Next, with respect to each photosensitive drum 10 on which the electrostatic latent image is formed in this way, the developer is guided to a position facing the photosensitive drum 10 by the developing roller 21 in the corresponding developing device 20, and a predetermined color is obtained. The toner is supplied to the electrostatic latent image on each photoconductive drum 10 for development, and a toner image of each color is formed on the surface of each photoconductive drum 10.

  Then, the toner images of the respective colors formed on the respective photosensitive drums 10 in this manner are respectively transferred to the intermediate transfer body 13 in the form of an endless belt that is driven across the roller 13a. A primary image is sequentially transferred by the transfer device 14 to form a full-color toner image on the intermediate transfer member 13. On the other hand, residues such as toner remaining on the surface of each photoreceptor drum 10 without being transferred to the intermediate transfer body 13 are removed by the first cleaning device 15.

  Next, the full-color toner image formed on the intermediate transfer member 13 as described above is guided to a position facing the secondary transfer device 16 formed into a roller shape by the intermediate transfer member 13 and the image forming apparatus. The recording sheet S accommodated in the lower part of the sheet is guided between the intermediate transfer member 13 and the secondary transfer device 16, and the full-color toner image formed on the intermediate transfer member 13 by the secondary transfer device 16 is transferred to the recording sheet S. Secondary transfer is performed on the recording sheet S.

  Thereafter, the recording sheet S to which the full-color toner image is transferred is guided to the fixing device 17, and the transferred full-color toner image is fixed to the recording sheet S, and then the recording in which the full-color toner image is fixed as described above. The sheet S is discharged. On the other hand, toner and other residues that are not transferred to the recording sheet S and remain on the intermediate transfer member 13 are removed from the intermediate transfer member 13 by the second cleaning device 18.

  Next, the developing device 20 in this embodiment will be specifically described.

  Here, in the developing device 20 in this embodiment, as shown in FIG. 2, the developing roller 21 is rotatably provided so as to face the photosensitive drum 10 with a predetermined interval therebetween, and the inside of the developing roller 21 is also provided. A magnet member 21a provided with a plurality of magnetic poles N, S,... Is fixedly provided on the circumferential side.

  Also, a first developer transport supply unit 22 and a second developer that are supplied to the developing roller 21 while transporting a developer including toner and a carrier along the axial direction of the developing roller 21 below the developing roller 21. An agent transport and supply unit 23 is provided via a partition wall 24.

  Further, in the developing device 20 of this embodiment, as shown in FIGS. 2 and 3, the rotation shaft 25 a is provided in each of the first developer transport supply unit 22 and the second developer transport supply unit 23. 26a, screw members 25, 26 provided with spiral screw blades 25b, 26b on the outer periphery thereof are provided along the developing roller 21, and between the developing roller 21 and the screw members 25, 26. The partition members 27 each having a plurality of supply ports 27a opened in the axial direction of the developing roller 21 are provided so as to extend from the upper part of the partition wall 24 to both sides thereof. .

  Then, the screw members 25 and 26 provided in the first developer conveyance supply unit 22 and the second developer conveyance supply unit 23 are rotated, and the developer is developed by the screw blades 25b and 26b in the screw members 25 and 26, respectively. Is transported in the opposite direction in the first developer transport and supply section 22 and the second developer transport and supply section 23, and the developer is transported and supplied to the first developer through the circulation sections 24a and 24b at both ends of the partition wall 24. The developer in the first developer transport supply unit 22 and the second developer transport supply unit 23 is circulated between the unit 22 and the second developer transport supply unit 23 by the screw blades 25b and 26b. The developing roller 21 is distributed and supplied through the supply ports 27a provided in the partition member 27.

  Next, the developing roller 21 to which the developer has been supplied as described above is rotated, and the developer roller 21 and the required roller are required in the middle of guiding the developer supplied to the developing roller 21 to the developing position facing the photosensitive drum 10. The amount of the developer guided to the developing position facing the photosensitive drum 10 by the developing roller 21 is regulated by the regulating member 28 provided so as to be opposed to each other with an interval therebetween. Is guided to a developing position facing the photosensitive drum 10 for development.

  Here, in the developing device 20 of this embodiment, as each of the screw members 25 and 26, the screw blades 25b and the spiral screw blades 25b having the same twist direction and pitch on the outer circumferences of the rotary shafts 25a and 26a, respectively. The screw member 25, 26 is used to rotate the screw members 25, 26 in the reverse direction, and the developer is supplied by the screw blades 25b, 26b of the screw members 25, 26 to the first developer transport supply unit 22a. And the second developer transport and supply unit 25b are transported in the opposite directions, and the developer in the first developer transport and supply unit 22a and the second developer transport and supply unit 25b is provided in each partition member 27. The toner is distributed and supplied to the developing roller 21 from the supply port 27a.

  If it does in this way, since a pair of above-mentioned screw members 25 and 26 rotate in the opposite direction, it will be in the state where the phase of screw blades 25b and 26b in each screw member 25 and 26 shifted about 180 degrees, and each screw member 25. , 26 by the screw blades 25b, 26b, the period of the developer supplied to the developing roller 21 through the supply ports 27a is shifted by approximately 180 degrees.

  When the period of the developer supplied to the developing roller 21 through each supply port 27a is shifted by about 180 degrees in this way, the uneven pitch of the developer supplied to the developing roller 21 by the screw blades 25b and 26b is reversed. Accordingly, the developer is distributed and supplied to the surface of the developing roller 21 in a state where the amount of the developer is made constant through each supply port 27a.

  In addition, since a constant amount of developer is distributed and supplied to the developing roller 21 in this way, it is not necessary to increase the amount of developer supplied to the developing roller 21 as in the prior art. When the amount of developer conveyed is regulated by the regulating member 28, the load applied to the developer is reduced, the developer is prevented from deteriorating, and the load applied to the rotation of the developing roller 21 can be reduced. It becomes like this.

  In the image forming apparatus using such a developing device 20, the amount of the developer guided to the developing position facing the photosensitive drum 10 by the developing roller 21 in each developing device 20 is uneven. Is suppressed, the developer is prevented from deteriorating, and good image formation without uneven density can be stably performed.

  In the developing device 20 of the above-described embodiment, as the screw members 25 and 26, those having only the screw blades 25b and 26b spiraled on the outer periphery of the rotary shafts 25a and 26a are used. In order to stably supply a constant amount of developer to the developing roller 21 through the supply ports 27a provided in the partition member 27 by the screw members 25 and 26, the respective members provided in the partition member 27. In correspondence with the position of the supply port 27a, as shown in FIG. 4, the screw members 25 and 26 are radially extended to send the developer to the supply ports 27a separately from the screw blades 25b and 26b. It is possible to provide the auxiliary members 25c and 26c.

10 Photosensitive drum (image carrier)
DESCRIPTION OF SYMBOLS 11 Charging device 12 Latent image forming device 13 Intermediate transfer member 13a Roller 14 Primary transfer device 15 First cleaning device 16 Secondary transfer device 17 Fixing device 18 Second cleaning device 20 Developing device 21 Developing roller (developer carrier)
21a Magnet member 22 1st developer supply conveyance part 23 2nd developer supply conveyance part 24 Partition 24a, 24b Circulation part 25, 26 Screw member 25a, 26a Rotating shaft 25b, 26b Screw blade 25c, 26c Auxiliary member 27 Partition member 27a Supply port 28 Restriction member S Recording sheet

Claims (6)

  The developer carrying body supplied with the developer including toner and carrier is rotated, and the developer carrying body conveys the developer toward the image carrying body, and the developer carried by the developer carrying body In the developing device in which the amount is regulated by the regulating member, a first developer transport supply that supplies the developer to the developer carrier while transporting the developer along the developer carrier below the developer carrier. And a second developer transport and supply section, and a screw member provided with a spiral screw blade on the outer periphery of the rotation shaft in each developer transport and supply section is provided along the developer carrying member and developed. A partition member having a plurality of supply ports opened in the axial direction of the developer carrier is provided between the developer carrier and each of the screw members, and a screw blade on each screw member is provided. The developer is transported in the opposite direction between the first developer transport and supply section and the second developer transport and supply section, and the developer is supplied to the developer carrier through the supply port. apparatus.   The developing device according to claim 1, wherein a cycle of supplying the developer to the developer carrier through a supply port provided in the partition member is shifted by a screw blade in each of the screw members. Developing device.   3. The developing device according to claim 2, wherein the supply port is shifted when the cycle of supplying the developer to the developer carrier through the supply port provided in the partition member by the screw blade in each of the screw members. A developing device characterized in that the cycle of the screw blades in each screw member for supplying the developer to the developer carrying member is shifted by 180 degrees.   4. The developing device according to claim 1, wherein the total amount of each developer supplied to the developer carrier through each supply port by the screw blades in each of the screw members is constant. A developing device characterized in that it is configured as described above.   5. The developing device according to claim 1, wherein each supply to each screw member is performed separately from the screw blade so as to correspond to a position of each supply port provided in the partition member. A developing device comprising an auxiliary member for feeding developer to a mouth.   6. An image forming apparatus, wherein a developer is conveyed to an image carrier by a developer carrier in the developing device according to claim 1, and development is performed.

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