JP2010197768A - Developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably perform proper development by suppressing the variations in the amount of developer in a developer supply transport path, even when a toner is supplied to the developer in a developing device. <P>SOLUTION: In the developing device transporting the developer D, containing the toner and carrier by transport members 15, 16 and circulating the developer between a developer supply transport path 13 supplying the developer to a developer carrier 11 and a developer circulation transport path 14, a buffer part 18 protruding upward for stagnating a part of the transported developer is provided in a position closer to an upstream side in the transport direction of the developer than the position where the developer is supplied to the developer carrier. The transport speed of the developer in the buffer part at a downstream side in the transport direction of the developer is slower than that at the upstream side. A transport amount regulating section 19 regulating the transport amount of the developer is provided between the buffer part and the position, where the developer is supplied to the developer carrier. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developing device used for developing an electrostatic latent image formed on an image carrier in an image forming apparatus such as a copying machine or a printer. In particular, development in which a developer containing toner and a carrier is guided to a position facing the image carrier and the developer is carried along a developer carrier to be developed, and the developer is supplied to the developer carrier. In a developing device comprising a developer supply transport path and a developer circulation transport path for transporting the developer by a transport member and circulating the developer between the developer supply transport path, the developer is carried on the developer carrier. This is characterized in that the amount of developer in the developer supply / conveyance path to be supplied is made constant so that good development can be stably performed.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, toner is supplied from a developing device to an electrostatic latent image formed on an image carrier such as a photoconductor, and the electrostatic latent image formed on the image carrier is The image is developed.

  Here, as such a developing device, there are known a two-component developing method using a developer including toner and a carrier and a one-component developing method using only toner without using a carrier. It has been.

  As a two-component developing type developing device using a developer containing toner and carrier, for example, as shown in FIGS. 1 and 2, a developer carrying member provided so as to face the image carrying member 1 A magnet member 11 a having a plurality of magnetic poles N, S,... Is provided on the inner circumference of the apparatus 11, and a partition wall 12 is provided in the apparatus main body 10 along the developer carrier 11. D is transported along the developer carrier 11 and the developer supply transport path 13 for supplying the developer D to the developer support 11 and the developer supply transport path 13 for transporting the developer D. The first and second transports are separated into the developer circulation transport path 14 for circulating the developer D, and transported while mixing the developer D in the developer supply transport path 13 and the developer circulation transport path 14 respectively. Provide members 15 and 16 With those having a circulation port 12a for circulating the developer 2 and the developer supplying path 13 developer circulation path 14. at both ends of the partition wall 12 is used.

  Here, in such a developing device, the first conveyance member 15 provided in the developer supply conveyance path 13 and the second conveyance member 16 provided in the developer circulation conveyance path 14 are rotated. The developer supply transport path 13 and the developer are mixed while the developer D containing the toner and the carrier is mixed by the transport blades 15b and 16b provided around the rotation shafts 15a and 16a of the transport members 15 and 16, respectively. The developer D is conveyed in the reverse direction in the circulation conveyance path 14, and the developer D is circulated in the developer supply conveyance path 13 and the developer circulation conveyance path 14 through the circulation port 12 a and is developed in the developer supply conveyance path 13. The agent D is supplied to the developer carrier 11.

  Then, the developer carrier 11 is rotated to convey the developer D toward the image carrier 1, and the amount of the developer D thus conveyed is regulated by the regulating member 17, so that the developer carrying is carried out. The body 11 guides a predetermined amount of developer D to the development area facing the image carrier 1 and supplies the toner in the developer D to the electrostatic latent image formed on the image carrier 1 for development. I have to.

  In addition, when the toner in developer D is supplied to the electrostatic latent image formed on image carrier 1 and developed, the toner concentration in developer D is generally reduced. Then, the toner is supplied from the toner replenishing device 3 to the developer D in the developer circulation conveyance path 14 through the toner replenishment port 3 a, and the developer D thus replenished is conveyed while being mixed in the developer circulation conveyance path 14. Then, the developer is guided to the developer supply / conveyance path 13 through the circulation port 12a, and is supplied to the developer carrier 11 while the developer D is conveyed in the developer supply / conveyance path 13 as described above.

  Here, when the toner is supplied to the developer D in this way, the amount of the developer D in the portion where the toner is supplied becomes larger than the amount of the developer D in the portion where the toner is not supplied. The amount of the developer D is increased, and the amount of the developer D is reduced as the carrier in the developer D is attached to the image carrier 1 and consumed. The portion where the amount of developer D is reduced is led to the developer supply transport path 13, or the developer D is guided from the developer circulation transport path 14 to the developer supply transport path 13 through the circulation port 12 a. Variations in the amount of developer D in the developer supply transport path 13 occurred due to fluctuations in the amount.

  For this reason, the amount of the developer D supplied from the developer supply / conveyance path 13 to the developer carrier 11 changes in the axial direction, and the electrostatic charge formed on the image carrier 1 from the developer carrier 11 is changed. The amount of toner supplied to the latent image also varies in the axial direction, resulting in uneven density in the formed image, and a regulating member 17 that regulates the amount of developer D supplied to the developer carrier 11. There is a problem that the load applied to the battery becomes large.

  Conventionally, as disclosed in Patent Document 1, the amount of the developer entering the toner supply path for supplying toner to the developing device is changed in accordance with the change in the toner concentration of the developer. Has proposed that the toner density in the developer is automatically controlled.

  However, even in this case, variation in the amount of developer in the developer supply / conveyance path cannot be properly prevented, and the above-described problems still exist.

JP 2004-198852 A

  In the present invention, a developer containing toner and a carrier is guided to a position opposite to the image carrier, and the developer is transported by a transport member along the developer carrier to be developed, and the developer is supplied to the developer carrier. The above-described problems in the developing device including the developer supply transport path to be performed and the developer circulation transport path for transporting the developer by the transport member and circulating the developer between the developer supply transport path and the developer supply transport path. It is a problem to solve the problem.

  That is, according to the present invention, in the developing device as described above, when the developer in the developing device is replenished with toner, the amount of the developer guided from the developer circulation conveyance path to the developer supply conveyance path through the circulation port is reduced. Even in the case of fluctuations, it is possible to suppress the variation in the amount of developer in the developer supply conveyance path, and to maintain the developer amount in the developer supply conveyance path to be constant and develop from the developer supply conveyance path. It is an object to stably supply a constant amount of developer to the agent carrier so that good development can be stably performed.

  In the present invention, in order to solve the above-described problems, the developer is transported by the transport member along the developer carrier that conducts development by guiding the developer including toner and carrier to a position facing the image carrier. A developer supply transport path for supplying the developer to the developer carrier, and a developer circulation transport path for transporting the developer by the transport member and circulating the developer between the developer supply transport path and the developer supply transport path. In the developing device having the above, a buffer portion protruding upward is provided to retain a part of the developer to be transported at a position upstream of the position in which the developer is supplied to the developer carrier in the transport direction of the developer. The developer transport speed in the buffer unit is set to be slower on the downstream side than the upstream side in the developer transport direction, and between the buffer unit and the position where the developer is supplied to the developer carrier. Transport amount It provided the conveyance amount regulating portion win.

  Here, in the developing device of the present invention, the development in the developer supply transport path is more in the developer supply transport path and the developer circulation transport path than the position where the developer is supplied to the developer carrier. It is preferable to provide an extending portion extending upstream in the transport direction of the agent, and to provide the buffer portion and the transport amount regulating portion in the extending portion in the developer supply transport path.

  In the developing device of the present invention, the developer conveyance speed in the conveyance amount regulating unit is set to be equal to or lower than the developer conveyance speed at a position where the developer is supplied to the developer carrier in the developer supply conveyance path. It is preferable.

  In the developing device of the present invention, when the toner replenishing portion for replenishing toner to the developer is provided, it is provided at a position upstream of the above-mentioned buffer portion in the developer transport direction.

  Further, in the developing device of the present invention, the buffer unit may be in a state of protruding upward so that the stayed developer is sequentially and appropriately guided to the transport amount regulating unit. However, it is preferable that the buffer portion protrudes upward in the vertical direction so that the stayed developer is promptly guided to the conveyance amount regulating portion.

  In the developing device of the present invention, a buffer portion protruding upward is provided at a position upstream of the position in which the developer is supplied to the developer carrying member in the developer conveyance direction, and the developer conveyance speed in this buffer portion The developer is delayed more downstream than the upstream side in the developer conveyance direction so that a part of the developer conveyed to the buffer unit is retained in the buffer unit, and the buffer unit and the developer carrying member are A conveyance amount regulation unit is provided between the developer supply position and the developer conveyance amount in this conveyance amount regulation unit.

  For this reason, in the developing device of the present invention, even when there is a portion where the amount of developer is increased due to the replenishment of toner, or when the amount of developer conveyed due to unevenness of conveyance fluctuates, The developer is temporarily retained in the buffer portion, while the developer remaining in the buffer portion is replenished to the portion where the amount of the developer is reduced, and is conveyed in the buffer portion. The amount of developer to be applied becomes constant. Further, the developer transported in the transport amount regulating unit is regulated to an appropriate amount, and an appropriate amount of developer is transported along the developer supply transport path to supply the developer to the developer carrier. The amount of developer at the position where the developer is supplied to the developer carrier is made constant at an appropriate amount, and a constant amount of developer is stabilized from the developer supply path to the developer carrier. Thus, good development can be stably performed.

  In the developing device of the present invention, the developer transport direction in the developer supply transport path is greater than the position where the developer is supplied to the developer carrier in the developer supply transport path and the developer circulation transport path. By providing an extension part extending upstream and providing the buffer part and the transport amount regulating part in the extension part in the developer supply transport path, the developer transported in the buffer part as described above is provided. The amount is made constant, and the developer regulated to an appropriate amount by the conveyance amount regulating unit is quickly guided to a position where the developer is supplied to the developer carrying member along the developer supply conveyance path. Thus, fluctuations in the amount of the developer guided to the position where the developer is supplied to the developer carrying member due to unevenness of conveyance and the like are further suppressed.

It is the schematic longitudinal cross-sectional view which showed the internal structure of the conventional image development apparatus. It is a schematic cross-sectional view showing the internal structure of a developing device according to a conventional embodiment. 1 is a schematic longitudinal sectional view showing an internal structure of a developing device according to an embodiment of the present invention. It is a schematic cross-sectional view showing the internal structure of the developing device according to the above embodiment. In the developing device according to the above-described embodiment, the developer supply conveyance path in which the buffer portion is provided in the extension portion that extends to the upstream side in the developer conveyance direction from the position where the developer is supplied to the developer carrier. It is sectional explanatory drawing which showed the state. In the developing device according to the above-described embodiment, it is a cross-sectional explanatory view showing an internal state of a conveyance amount regulating portion provided between a buffer portion and a position where a developer is supplied to the developer carrying member.

  Next, a developing device according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. Note that the developing device according to the present invention is not limited to the one shown in the following embodiment, and can be appropriately changed and implemented without changing the gist thereof.

  Also in the developing device in this embodiment, as shown in FIGS. 3 and 4, a cylindrical shape in which a developer D containing toner and a carrier is accommodated in the apparatus main body 10 and the developer D is conveyed to the photoreceptor 1. The developer carrying member 11 is rotatably provided so as to face the photosensitive member 1 with a predetermined distance therebetween, and a plurality of magnetic poles N, S,... Are magnetized inside the developer carrying member 11. A magnet roller 11a is provided.

  Here, in the developing device in this embodiment, a partition wall 12 is provided in the apparatus main body 10 along the developer carrier 11, and the developer D is passed along the developer carrier 11 by the partition wall 12. Development in which the developer D is conveyed between the developer supply transport path 13 for supplying the developer D to the developer carrier 11 and the developer D transported between the developer supply transport path 13 and the developer supply transport path 13. When separating into the developer circulation conveyance path 14, the developer supply conveyance path is positioned more than the position where the developer D is supplied to the developer carrier 11 in the developer supply conveyance path 13 and the developer circulation conveyance path 14. In FIG. 13, extending portions 13 a and 14 a extending upstream in the transport direction of the developer D are provided, and the partition wall 12 is extended to the extending portions 13 a and 14 a.

  The developer supply transport path 13 and the developer circulation transport path 14 provided with the extending portions 13a and 14a as described above are provided with transport blades 15b and 16b around the rotation shafts 15a and 16a, respectively. In addition to providing the first and second transport members 15 and 16, circulation ports 12 a for circulating the developer 2 in the developer supply transport path 13 and the developer circulation transport path 14 are provided at both ends of the partition wall 12. ing.

  Further, in the developing device in this embodiment, as shown in FIG. 5, the protruding portion 13a in the developer supply transport path 13 protrudes upward in the vertical direction for retaining a part of the transported developer D. A transport amount regulating unit 19 that regulates the transport amount of the developer D so as to be continuous with the buffer unit 18 on the downstream side in the transport direction of the developer D from the buffer unit 18. It is provided between the developer carrier 11 and the position where the developer D is supplied.

  Here, in providing the first conveying member 15 provided with the conveying blade 15b around the rotating shaft 15a in the developer supply conveying path 13, the downstream side in the buffer unit 18 is provided. The pitch pa of the conveying blade 15b1 in the portion of the conveying amount regulating portion 19 is made smaller than the pitch p of the conveying blade 15b on the upstream side and the downstream side, and the developer D conveyed by the conveying member 15 Of the developer D in the buffer unit 18 in the downstream side of the upstream side in the transport direction of the developer D, and a part of the developer D guided to the buffer unit 18 stays in the buffer unit 18. I try to let them. Similarly, in the transport amount regulating unit 19 that is continuous with the buffer unit 18, similarly, the transport rate of the developer D is decreased, and the amount of the developer D that is guided to the position where the developer D is supplied to the developer carrier 11. To regulate. Note that, as described above, the transport speed of the developer D in the buffer section 18 is slowed down in the downstream portion relative to the upstream portion in the transport direction, and a part of the developer D guided to the buffer section 18 is removed. In order to allow the developer D to stay in the buffer unit 18 appropriately and without deficiency in the buffer unit 18, the transport direction with respect to the transport speed v1 of the developer D on the upstream side in the transport direction of the buffer unit 18. The ratio (v2 / v1) of the conveyance speed v2 of the developer D on the downstream side is preferably in the range of 0.3 to 0.5.

  Further, when the amount of the developer D guided to the position where the developer D is supplied to the developer carrying member 11 from the buffer unit 18 through the transport amount regulating unit 19 is regulated in this way, it stays in the buffer unit 18. In order to prevent the developed developer D from flowing into the carry amount regulating unit 19 without permission, the space between the carrying member 15 and the carry amount regulating unit 19 is reduced.

  In the developing device according to this embodiment, in order to reduce the space between the conveyance member 15 and the conveyance amount regulating unit 19, as illustrated in FIG. 6, the conveyance attached to the rotation shaft 15 a of the conveyance member 15. The area S occupied by the blade 15b1 is set to be larger than the area S1 occupied by the space between the conveyance blade 15b1 and the conveyance amount regulating unit 19. In order to appropriately regulate the amount of the developer D guided to the position where the developer D is supplied to the developer carrying member 11 in the transport amount regulating unit 19, the transport amount regulating unit 19 is based on the area S occupied by the carry blade 15b1. It is preferable that the ratio (S1 / S) of the area S1 occupied by the space is in the range of 0.2 to 0.4.

  Also in this developing device, the first transport member 15 provided in the developer supply transport path 13 and the second transport member 16 provided in the developer circulation transport path 14 are rotated, and the first transport member 15 is rotated. In the first and second transport members 15 and 16, the developer supply and transport is performed while the developer D containing toner and carrier is mixed by the transport blades 15b, 15b1 and 16b provided around the rotation shafts 15a and 16a. The developer 13 is conveyed in the opposite direction between the path 13 and the developer circulation conveyance path 14, and the developer D is circulated in the developer supply conveyance path 13 and the developer circulation conveyance path 14 through the circulation port 12a, and the developer supply conveyance path. In FIG. 13, the developer D is supplied to the developer carrier 11.

  Then, the developer carrier 11 is rotated to convey the developer D toward the image carrier 1, and the amount of the developer D thus conveyed is regulated by the regulating member 17. 11, a predetermined amount of developer D is guided to a developing area facing the image carrier 1, and toner in the developer D is supplied to the electrostatic latent image formed on the image carrier 1 for development. ing.

  In addition, when the toner in developer D is supplied to the electrostatic latent image formed on image carrier 1 and developed, the toner concentration in developer D decreases. The toner is replenished from the replenishing device 3 to the developer D in the developer circulation conveyance path 14 through the toner replenishing port 3a, and the developer D thus replenished is conveyed while being mixed in the developer circulation conveyance path 14, The developer is guided to the developer supply transport path 13 through the circulation port 12a.

  Here, in the developing device of this embodiment, when the developer D is guided to the extending portion 13a of the developer supply transport path 13 from the extending portion 14a in the developer circulating transport path 14 through the circulation port 12a, After the developer D is conveyed by the conveying blades 15b having a predetermined pitch p provided on the first conveying member 15 and guided to the upstream portion in the buffer portion 18, the downstream portion in the buffer portion 18 is conveyed. Is guided to the conveying blade 15 b 1 having a small pitch pa, and the conveying speed of the developer D is decreased, and a part of the developer D is retained in the buffer unit 18.

  For this reason, when the portion where the amount of the developer D is increased due to the replenishment of the toner as described above is introduced to the buffer unit 18 or when the amount of the developer D conveyed varies due to unevenness of conveyance or the like. However, the excessive developer D is temporarily retained in the buffer unit 18, while the developer D retained in the buffer unit 18 is replenished to the portion where the amount of the developer D is reduced. Thus, the amount of the developer D conveyed in the buffer unit 18 is made constant.

  In the developing device of this embodiment, as described above, the transport amount that regulates the transport amount of the developer D so as to be continuous with the buffer unit 18 on the downstream side in the transport direction of the developer D from the buffer unit 18. A restricting portion 19 is provided, and the pitch pa of the conveying blade 15b1 of the conveying member 15 in the conveying amount restricting portion 19 is made the same as the downstream portion in the buffer portion 18 to reduce the conveying speed of the developer D and to convey Since the space between the amount regulating unit 19 and the conveying member 15 is reduced, the developer D staying in the buffer unit 18 is prevented from flowing into the conveying amount regulating unit 19 without permission, and the conveyance amount regulating is performed. The developer D conveyed in the section 19 is restricted to an appropriate amount.

  The amount of developer D thus transported is regulated to an appropriate amount by the transport amount regulating unit 19, and after passing through the carry amount regulating unit 19, the developer D is provided on the transport member 15. The developer is transported along the developer supply transport path 13 by the transport blades 15b having a predetermined pitch p, and is guided to a position where the developer D is supplied to the developer carrier 11 and used for development.

  For this reason, in the developing device of this embodiment, the developer is supplied even when the amount of the developer D increases due to the replenishment of toner, or when the amount of the developer D conveyed varies due to uneven conveyance. A constant amount of developer D is stably guided to the position where the developer D is supplied to the carrier 11, and a constant amount of developer is supplied from the developer supply transport path 13 to the developer carrier 11. D is supplied uniformly and stably, and good development can be performed stably.

  In the developing device of this embodiment, the transport speed of the developer D transported by the transport member 15 is set so that the downstream portion of the buffer unit 18 in the transport direction of the developer D and the transport amount regulation are restricted. In order to slow down the part 19, the conveying member 15 is provided with conveying blades 15b1 having a small pitch pa in these parts. However, the developer D conveying speed is set to the upstream side in the conveying direction of the developer D in the buffer unit 18. The method of slowing down in the downstream part and the conveyance amount regulation part 19 is not limited to this. For example, in the portion of the buffer unit 18 on the downstream side in the conveyance direction of the developer D and the conveyance amount regulating unit 19, the rotation shaft 15a of the conveyance member 15 is thickened, and the radial direction of the conveyance blade 15b provided on the rotation shaft 15a. It is also possible to reduce the amount of protrusion of the toner and to reduce the transport speed of the developer D in this portion.

  In the developing device of this embodiment, the buffer portion 18 and the conveyance amount regulating portion 19 are provided in the extending portion 13a in the developer supply conveyance path 13 as described above. The position where the amount restricting portion 19 is provided is not limited to such a position, and may be provided in the developer circulation conveyance path 14. Further, when the buffer unit 18 and the conveyance amount regulating unit 19 are provided in the developer circulation conveyance path 14 as described above, the extension portion as described above is provided in the developer supply conveyance path 13 and the developer circulation conveyance path 14. It is also possible not to provide 13a and 14a.

DESCRIPTION OF SYMBOLS 1 Photoconductor 3 Toner replenishing apparatus 3a Toner replenishing port 10 Apparatus main body 11 Developer carrier 11a Magnet roller 12 Partition wall 12a, 12b Circulation port 13 Developer supply conveyance path 13a Extension part 14 Developer circulation conveyance path 14a Extension part DESCRIPTION OF SYMBOLS 15, 16 Conveyance member 15a, 16a Rotating shaft 15b, 15b1, 16b Conveyance blade | wing 17 Control member 18 Buffer part 19 Conveyance amount control part D Developer

Claims (5)

  A developer supply that feeds the developer to the developer carrier and transports the developer to the developer carrier along the developer carrier that conducts development by introducing the developer including toner and carrier to a position facing the image carrier. In a developing device that includes a transport path and a developer circulation transport path that transports the developer by a transport member and circulates the developer between the developer supply transport path and the developer supply transport path. Provided at a position upstream of the supply position with respect to the developer conveyance direction is a buffer section protruding upward that retains a part of the developer to be conveyed. In addition, a conveyance amount regulating unit that regulates the conveyance amount of the developer is provided between the buffer unit and the position where the developer is supplied to the developer carrying member. Characteristic developing equipment .   The developer in the developer supply transport path in the developer supply transport path and the developer circulation transport path in the developing device according to claim 1, rather than a position where the developer is supplied to the developer carrier. A developing device comprising: an extending portion extending upstream in the conveying direction; and the buffer portion and the conveying amount regulating portion provided in the extending portion of the developer supply conveying path.   3. The developer according to claim 1, wherein the developer conveyance speed in the conveyance amount regulating unit is set so that the developer is conveyed at a position where the developer is supplied to the developer carrier in the developer supply conveyance path. A developing device characterized in that the speed is lower than the speed.   4. The developing device according to claim 1, further comprising a toner replenishing unit that replenishes the developer with toner at a position upstream of the buffer unit in the developer transport direction. 5. A developing device.   5. The developing device according to claim 1, wherein the buffer section protrudes upward in the vertical direction. 6.

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