JP4151958B2 - Developing device, image forming apparatus, and process cartridge - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a developing device, an image forming apparatus, and a process cartridge.
[0002]
[Prior art]
[Patent Document 1]
JP 2001-331024 A
[Patent Document 2]
Japanese Patent Laid-Open No. 2001-331525
[Patent Document 3]
JP-A-10-221937
[Patent Document 4]
Japanese Patent No. 3319844
[0003]
As an image forming apparatus such as a copying machine, a printer, a facsimile machine, etc., an electrophotographic process is used to form a latent image on a latent image carrier, and this latent image is developed using a two-component developer composed of toner and carrier. Some images are formed by forming a visible image and transferring the toner image to a recording medium, or transferring the toner image to an intermediate transfer member and then transferring the toner image to a recording medium.
[0004]
In such an image forming apparatus, the developer obtained by conveying the toner and the carrier while stirring must be uniformly distributed over the entire length of the image carrier. Therefore, generally, as shown in FIG. 19, a toner agitating and conveying screw 500 having a spiral screw 502 formed on the outer periphery of the main shaft portion 501 is installed in the toner supplying portion to agitate and convey the toner. Like to do.
[0005]
Further, as an attempt to improve such a toner agitating and conveying screw, for example, as disclosed in Japanese Patent Application Laid-Open No. H10-260260, a developer agitating member that rotates is provided, and the agitating member is in the direction of rotation of the rotating shaft. In which blades (fins) are provided in a comb (staggered) shape at a position opposite to each other, as disclosed in [Patent Document 2], in addition to the structure of Patent Document 1, the stirring member further rotates. It has a function of adjusting the stirring state by changing the ratio of the stirring portion and the non-stirring portion of the stirring member, and as disclosed in [Patent Document 3], the inclination angle of the stirring blade of the stirring screw As disclosed in [Patent Document 4], agitating blades are provided at predetermined intervals, provided with an inclination with respect to the rotation axis, and provided with a pumping plate material shifted by a predetermined angle with respect to the rotation axis. Etc. .
[0006]
[Problems to be solved by the invention]
However, in the toner stirring and conveying screw shown in FIG. 20 described above, since the screw 502 is merely connected in series, the toner can be conveyed in the axial direction, but the toner is supplied to the carrier at the conveyance start point. However, due to electrostatic force and interparticle force, the toner may be transported without being sufficiently mixed without being uniformly mixed, and a uniform toner thin film may not be obtained on the outer periphery of the developer carrier. There is a problem that there is.
[0007]
Therefore, as described in [Patent Document 1] and [Patent Document 2], in addition to the fins arranged parallel to the axial direction and perpendicular to the rotational direction, the pitch of the screw portion of the toner stirring and conveying screw is narrowed. Alternatively, as shown in FIG. 20, a measure is taken to increase the agitation effect by providing fins 503 at right angles between the screws while the toner is conveyed from the supply point to the screw end.
[0008]
However, if the main shaft is provided with fins that face at right angles to the rotation direction, it will be an obstacle to toner transfer, and the torque for rotating the screw or main shaft will increase, resulting in higher power consumption. There is a problem that the decrease in the temperature is remarkable.
[0009]
In addition, as a recent requirement for developing devices, as the amount of toner consumption per unit time increases as printing and copying speeds up, the toner is rapidly replenished and the developer is sufficiently mixed and stirred in a short time. Therefore, it is necessary to increase the charge amount of the toner to a level suitable for development. The conventional agitating / conveying means having screw-like blades cannot meet such a demand.
[0010]
The present invention has been made in view of the above problems, and an object thereof is to provide a developing device excellent in stirring and conveying properties, a process cartridge including the developing device, and an image forming apparatus.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, a developing device according to the present invention provides: Placed in the stirring tank An agitation means for agitating the developer and a toner that conveys the toner to the development area by a traveling wave electric field -Carrying Between the feeding means, the stirring means and the toner conveying means. The bottom of the stirring tank The mesh electrode placed on the , Have Apply the same charge voltage as the toner to the mesh electrode The configuration.
[0012]
Here, the stirring means can be a screw.
[0013]
Further, it is preferable that the agitation unit has a plurality of flat plate-like members arranged at different positions in the axial direction on the peripheral surface of the main shaft and has a developer agitation and charging function. In this case, it is preferable that triangular projections are formed on the surfaces of the plurality of flat plate members of the stirring means, and the axial direction is different in the portion of the main shaft of the stirring device where the flat plate members are not provided. It is preferable that a plurality of rib members are provided at positions, and a triangular protrusion is formed on the surface of the rib member. Further, the stirring means can stir the developer by a butterfly method or a pendulum method.
[0014]
Furthermore, the stirring means can have a brush structure, and in this case, the stirring means is preferably in contact with the mesh electrode.
[0015]
Moreover, it is preferable that the charging functional material is formed on the surface of the stirring means. Furthermore, it is preferable that the charging functional material is formed on the inner surface of the stirring tank in which the stirring means is disposed.
[0016]
The process cartridge according to the present invention includes at least one of an image carrier, a charging unit, a transfer unit, and a cleaning unit and the developing device according to the present invention, and is configured to be detachable from the main body of the image forming apparatus. It is.
[0017]
The image forming apparatus according to the present invention includes the developing device according to the present invention or the process cartridge according to the present invention.
[0018]
An image forming apparatus according to the present invention includes a plurality of process cartridges according to the present invention.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings. A first embodiment of the present invention will be described with reference to FIGS. 1 is a schematic configuration diagram for explaining a developing device portion according to the present invention of the image forming apparatus of the embodiment, and FIG.
[0020]
A developing device 2 that develops an electrostatic latent image formed on an image carrier (in this example, a photosensitive drum) 1 using a two-component developer including toner T and carrier C stirs toner T and carrier C. The toner supply unit 11 for supplying the toner and the toner T supplied from the toner supply unit 11 are conveyed toward the developing unit (development area) of the image carrier 1 to form an electrostatic latent image formed on the image carrier 1. Toner electrostatic conveying means 12 for developing the toner.
[0021]
The toner supply unit 11 includes a developing container 21 that stores a developer composed of toner T and carrier C. The developing container 21 includes a toner hopper unit 22 to which toner is supplied from a toner cartridge (not shown), and the toner T and carrier C. And a stirring tank 23 that charges and charges the partition wall 24 with a partition member 24.
[0022]
An agitator 26 that stirs and conveys the developer (toner T, carrier C) is rotatably disposed in the toner hopper 22. Further, a developer stirring and conveying screw 27 serving as a rotating stirring means that is a rotating member that stirs the toner T and the carrier C conveyed from the toner hopper 22 and frictionally charges the stirring tank 23 is provided on the inner wall surface of the developing container 21. The mesh electrode 28 is disposed on the bottom surface.
[0023]
Here, the developer agitating / conveying screw 27 supplies toner at one end in the length direction and is uniform to the developer (toner T, carrier C) circulating while being conveyed to the other end. As shown in FIG. 3, a spiral screw portion 32 is formed on the peripheral surface of the main shaft portion 31, and the inorganic fine particles 33 serving as a charging functional material with respect to the toner T are formed on the surface of the screw 27. For example, a Chita Bali glass powder (average particle size: 5 μm) 33 is formed by high-speed spraying.
[0024]
Examples of the material for the developer stirring and conveying screw 27 include resins such as synthetic resin PE (polyethylene), PC (polycarbonate), PETP (polyethylene terephthalate), PP (polypropylene), and ABS (acrylonitrile butadiene styrene). A material, further, SUS, aluminum, iron, copper, or an alloy thereof can also be used. Moreover, what formed the electroconductive film | membrane on the surface of the said resin material is also possible.
[0025]
The screw material is required to have a low thermal deformation property, excellent heat resistance and non-adhesiveness with toner, and excellent dimensional stability and strength. In the resin material, resin reinforced with glass fiber such as carbon or aramid is used as the resin material. Among them, ABS resin / PC resin (with 30% glass fiber) is inexpensive and has heat stability and is preferably used. Is done.
[0026]
The electrostatic toner transporting unit 12 includes a set of three electrodes (transport electrodes) 42a, 42b, and 42c on a base substrate (support substrate) 41, and a toner transfer direction (toner traveling direction, toner movement) at a predetermined interval. Direction: the direction indicated by the arrow in FIG. 2) is repeatedly formed and arranged in a direction substantially perpendicular to the toner transfer direction, and an insulating conveyance surface forming member 43 that forms a conveyance surface is laminated thereon. is there.
[0027]
The end portions of the transport electrodes 42a, 42b, and 42c are connected to the common electrodes 45a, 45b, and 45c, respectively, and three-phase drive waveforms (A phase, B phase and C phase) are applied.
[0028]
Accordingly, the traveling wave electric field is generated by applying the three-phase driving waveforms (A phase, B phase, C phase) out of phase from the driving circuit 46 to the transport electrodes 42a, 42b, 42c of the electrostatic toner transport means 12. The developer that is generated and supplied from the toner supply unit 11 is conveyed to the developing unit by the electrostatic force by the toner conveying unit 12, and the electrostatic latent image of the image carrier 1 is transported and hopped in the developing unit by the ETH phenomenon. The image is developed.
[0029]
Since it is configured in this manner, first, toner is replenished in the toner hopper 22 of the developing device 2 from a toner cartridge (not shown) in a line from the front to the back in FIG. At this time, a developer composed of toner T and carrier C is generated by mixing and stirring with the agitator 26 rotating in the clockwise direction, and is fed into the stirring tank 23. At this point (hopper 22), the toner T is charged to some extent by mixing and stirring.
[0030]
Then, the developer agitating / conveying screw 27, which is a rotary agitating means disposed in the agitation tank 23, is rotated clockwise to charge the developer while stirring again. Here, a developer (toner T) stirred and charged at the position of the mesh electrode 28 is applied to the mesh electrode 28 disposed at the bottom of the stirring tank 23 by applying a voltage having the same charge as that of the toner T by the power source 29. , Carrier C) is composed of electrostatic toner transporting means 12 that receives a voltage of the same charge as toner T, and in which toner T adsorbed on the peripheral surface of carrier C is disposed at a position opposed to the opening hole of mesh electrode 28. It is sent almost uniformly to the developer conveying means.
[0031]
Next, the toner T sent to the electrostatic toner transport means 12 is applied with the three-phase (A phase, B phase, C phase) driving waveforms out of phase to the transport electrodes 42a, 42b, 42c. And is conveyed to the developing area (developing part) of the image carrier 1. Then, the electrostatic latent image formed on the surface of the image carrier 1 is developed in the development area facing the image carrier 1 to form a toner image.
[0032]
On the other hand, since the stirring tank 23 and the toner hopper section 22 have an opening 24a in the upper part of the partition plate 24, a part of the developer (toner T and carrier C) is recirculated from the stirring tank 23 to the hopper section 22 side. Since the newly replenished toner is stirred again, mixing and stirring are sufficiently performed.
[0033]
In the present embodiment, a screw in which a molten resin of ABS resin / PC resin containing 30% glass fiber having a main axis of 6 mm, a length of 230 mm, and a screw region of 175 mm is injected as a spiral screw 27 as shown in FIG. A developer agitating and conveying screw in which inorganic fine particles (average particle size: 5 microns) 33 serving as a charging functional material for the toner was formed on the screw surface by high-speed jetting was disposed on the screw surface.
[0034]
Then, the developer agitating and conveying screw 27 is rotated at a peripheral speed of 60 mm / sec, and the toner pattern sent out from the mesh electrode area of the toner T feed area 5 × 100 mm is visually observed with the polymerization toner having an average particle diameter of 7 μm. As a result, it was confirmed that there was no toner unevenness.
[0035]
As described above, in a developing device that develops an electrostatic latent image formed on an image carrier with a two-component developer including toner and a carrier, a stirring unit including a rotating member that stirs the developer, and a toner in a developing region. In addition, a developing device having excellent agitating / conveying property can be obtained by including the electrostatic toner conveying unit that conveys the traveling wave in the traveling wave electric field and the mesh electrode disposed between the agitating unit and the toner conveying unit.
[0036]
The structure is simple by using the screw member as the stirring means, and efficient charging by stirring can be performed by forming the charging functional material on the surface of the screw member.
[0037]
Next, a second embodiment of the present invention will be described with reference to FIG. 2 is a schematic configuration diagram for explaining a developing device portion according to the present invention of the image forming apparatus of the embodiment.
In this embodiment, a stirring member 57 that rotates as a stirring means is disposed in the stirring tank 23.
[0038]
As shown in FIG. 5, the stirring member 57 has a plurality of stirring fins 62, which are plate-like members, arranged on the circumferential surface of the main shaft 61 at positions different from each other in the axial direction. Specifically, the two stirring fins 62 and 62 are arranged on the opposite side of the main shaft 61 (with a 180 ° positional relationship), and the stirring fins 62 and 62 adjacent in the axial direction shift the positional relationship by 90 degrees. And arranged in a comb shape (staggered shape).
[0039]
Further, a rib 63 is disposed between the fin stirring 62 and 62 of the stirring member 57. In this case, the stirring fins 62 and 62 are in an axially symmetric position in the upper and lower portions, and in the left and right portions, the left and right fins 62 are positioned between the upper and lower fins 62 and the ribs 63 are The upper and lower, left and right stirring fins 62 are disposed.
[0040]
Then, as shown in FIG. 6, a triangular protrusion 65 is provided on the surface (both sides) of the stirring fin 62, and as shown in FIG. In this relation, a triangular protrusion 66 is provided at a position facing in the axial direction.
[0041]
Since it is configured in this manner, as in the first embodiment, first, toner is replenished in the toner hopper 22 of the developing device 2 from a toner cartridge (not shown) in a line from the front to the back in FIG. At this time, a developer composed of toner T and carrier C is generated by mixing and stirring with the agitator 26 rotating in the clockwise direction, and is fed into the stirring tank 23. At this point (hopper 22), the toner T is charged to some extent by mixing and stirring.
[0042]
Then, by rotating the stirring member 57, which is a rotary stirring means arranged in the stirring tank 23, in the clockwise direction (the direction indicated by the arrow A in FIG. 5), the developer is again fed by the stirring fins 62 and the rib 63 as shown in FIGS. 7 is charged while stirring in the direction indicated by arrow B with turbulent flow.
[0043]
Here, a developer (toner T) stirred and charged at the position of the mesh electrode 28 is applied to the mesh electrode 28 disposed at the bottom of the stirring tank 23 by applying a voltage having the same charge as that of the toner T by the power source 29. , Carrier C) is composed of electrostatic toner transporting means 12 that receives a voltage of the same charge as toner T, and in which toner T adsorbed on the peripheral surface of carrier C is disposed at a position opposed to the opening hole of mesh electrode 28. It is sent almost uniformly to the developer conveying means.
[0044]
Next, the toner T sent to the electrostatic toner transport means 12 is applied with the three-phase (A phase, B phase, C phase) driving waveforms out of phase to the transport electrodes 42a, 42b, 42c. And is conveyed to the developing area (developing part) of the image carrier 1. Then, the electrostatic latent image formed on the surface of the image carrier 1 is developed in the development area facing the image carrier 1 to form a toner image.
[0045]
On the other hand, since the stirring tank 23 and the toner hopper part 22 are provided with an opening 24a above the partition plate 24, a part of the developer (toner T and carrier C) is recirculated from the stirring tank 23 to the hopper part 22 side. Since the newly replenished toner is stirred again, mixing and stirring are sufficiently performed.
[0046]
Here, the conveyance and stirring (diffusion) of the developer by the stirring fin 62 will be described with reference to FIG.
With the rotation of the stirring fin 62, the developer is conveyed in the rotation direction. Here, a triangular protrusion 65 is formed at the substantially central portion of the stirring fin 62. Therefore, the developer (toner, carrier) is started to be pushed from the apex (triangular apex) of the protrusion 65 by the rotation. The pressed developer is agitated and conveyed left and right (in the direction of arrow B) along the inclination of the protrusion 65, and the surrounding developer is also agitated and conveyed at the same time. Since the stirring fins 62 having the triangular protrusions 65 are provided every time they are rotated by 90 degrees, they are successively conveyed left and right and stirred (diffused), and the toner concentration in the stirring tank 23 is made uniform. .
[0047]
Next, the function of the rib 63 will be described with reference to FIG.
The rib 63 is provided with a triangular projection 66 in the same direction as the axial direction of the main shaft 61 around the columnar member, and is arranged at a position between the stirring fin 62 and the stirring fin 62. The rib 63 has a function of further stirring the developer conveyed in the left-right direction by the stirring fin 62. The developer is conveyed left and right along a partial arc shape of the rib 63, and further conveyed (diffused) in the inclination direction of the triangular protrusion 66, so that the developer is more uniform.
[0048]
In the present embodiment, the stirring member 57 as shown in FIG. 5 is injected into the developing container 21 with a molten resin of ABS resin / PC resin containing 30% glass fiber having a main axis of 6 mm, a length of 230 mm, and a stirring fin area of 175 mm. The member was placed.
[0049]
Then, the stirring member 57 was rotated at a peripheral speed of 60 mm / sec, and a mesh electrode 28 (opening hole 0.2 × 0.15 mm) made of SUS 0.3 mm as a carrier with φ0.3 mm as a carrier with a polymerization toner having an average particle diameter of 7 μm. As a result of visually observing the toner pattern delivered from the mesh electrode area with the toner delivery area of 5 × 100 mm, it was confirmed that there was no toner unevenness.
[0050]
As described above, as the stirring means including the rotating member, a plurality of flat plate-like members are arranged on the peripheral surface of the main shaft at positions different from each other in the axial direction, and the developer is stirred and charged. The stirring and charging efficiency can be improved. In this case, the stirring and charging efficiency can be further improved by forming a triangular protrusion on the surface of the flat plate member.
[0051]
In addition, a plurality of rib members are provided at different positions in the axial direction in a portion of the main shaft of the stirring unit where the flat plate member is not provided, and a triangular protrusion is formed on the surface of the rib member, so that the main shaft The stirring in the radial direction and the axial direction can be easily performed, and the stirring and charging efficiency are further improved.
[0052]
Next, a third embodiment of the present invention will be described. In the second embodiment described above, instead of rotating the stirring member 57 in the clockwise direction, the stirring fins 62 and the ribs 63 are arranged in a butterfly (pendulum) system using two stirring members 57 having the same configuration. Drove.
[0053]
Even in this configuration, since the triangular protrusions 65 are formed on both surfaces of the stirring fin 62, the stirring is performed by the reciprocating motion of the stirring member 57. As a result, as in the second embodiment in which the agitating member 57 is rotated, it was confirmed that the toner electrostatic conveyance unit 12 has no toner unevenness.
[0054]
Next, a fourth embodiment of the present invention will be described with reference to FIG. 2 is a schematic configuration diagram for explaining a developing device portion according to the present invention of the image forming apparatus of the embodiment.
In this embodiment, a roll-shaped brush (fur brush) 77 that rotates as a rotating stirring means is used in the stirring tank 23.
[0055]
Here, the fur brush (roll brush) 77 is installed to be rotatable in the right (clockwise) direction. As shown in FIG. 9, the fur brush 77 has a structure in which an insulating fiber (brush) 82 is wound around a core metal 81 such as SUS, and the insulating fiber 82 has a thickness of 0.1 to 1 mm and a planting density of 4 Up to 200,000 pieces, a pile length of 1 to 15 mm and made of nylon were used. Further, as shown in the figure, the fur brush 77 is installed so that the brush tip is in contact with the mesh electrode 28, and the mesh electrode 28 is applied with the same charge with the same hole diameter as in the above embodiment. Yes.
[0056]
With this configuration, the carrier C and the toner T to be replenished in the toner hopper 22 of the developing container 21 are mixed and stirred by the agitator 26, fed into the stirring tank 23, and fed to the fabrush 77 which is a rotary stirring means. It is charged to a selected charge (negative) by contact.
[0057]
The toner T is frictionally (contacted) charged with the carrier (titanium glass) C, and at the same time, the toner T is negatively charged by contacting the insulating fiber 82 of the fur brush 77. At this time, the toner T is carried between the fibers of the fur brush 77 and on the surface thereof by an adhesion force such as a mirror image force, and the charged toner that has reached the position of the mesh electrode 28 along with the rotation of the fur brush 77 is removed from the brush by an electric field. It becomes easy to leave. Further, the electrostatically adsorbed toner has a mechanical peeling force, and the toner is easily separated from the brush. Therefore, the toner can be easily supplied. Moreover, the clogging of the mesh can be prevented.
[0058]
Then, the toner is conveyed to the electrostatic toner conveying means 12 disposed on the mesh facing side from the opening hole of the mesh electrode 28. Also here, as a result of observing the banding of the toner T sent to the electrostatic toner transporting means 12, it was confirmed that no toner unevenness was observed as in the above embodiment.
[0059]
Next, a fifth embodiment of the present invention will be described with reference to FIGS. 10 is an explanatory view of the stirring fin of the stirring member of the same embodiment, FIG. 11 is an explanatory view of the rib of the stirring member, and FIG. 12 is a sectional explanatory view of the stirring fin.
In this embodiment, using the stirring member 57 (see FIG. 5) of the second embodiment, the material for forming the main shaft 61, the stirring fin 62, and the rib 63 of the stirring member 57 is made to contain charged fine particles 93. Yes.
[0060]
Specifically, charged material fine particles 93 made of the same material as the carrier C were contained. For example, ABS resin / PC resin (with 20% glass fiber) kneaded with titavari glass powder (average diameter 9 μm), injected with molten resin, and molded after cooling. When the molded product (titer content rate 20%) is observed with a microscope, as shown in FIG. 10 to FIG. 12, the resin surface is embedded in a form in which a part of the tabular glass powder (charged material fine particles 93) is exposed. confirmed. As another forming method, the ultrafine particles can be directly formed on the resin surface by high-speed injection.
[0061]
By using the stirring member 57 formed in this way, in the conveyance and stirring by the stirring fins 62 and the ribs 63, more efficient stirring can be achieved by friction (contact) with the fine particles 93 in addition to friction (contact) with the carrier C. , Charging is obtained.
[0062]
Furthermore, by adding the fine particles 93 to the inner wall surface of the developing container 21, further stirring and charging efficiency can be achieved.
[0063]
Here, as the functional material of the stirrer member, chitabari glass is used, but glass powder made of materials such as alumina glass and soda glass may be used. An organic material such as polyimide can also be used.
[0064]
As shown in FIG. 13, the first, second, and fourth embodiments described above are shown in FIG. 13 as a test apparatus (note that the figure shows the stirring member 57 of the second embodiment, but in the first embodiment, the screw 27, In the fourth embodiment, the peripheral speed of the rotary stirring means is rotated at 60 mm / sec by a fur brush 77), and toner containing 4% by weight of the toner component is supplied to this and stirred for a predetermined time, respectively. The toner was collected with the points A, B, and C as measurement points, and the charge amount was measured by the blow-off method.
[0065]
As a result, FIG. 14 (first embodiment), FIG. 15 (second embodiment), and FIG. 16 (fourth embodiment) are shown. In each of the embodiments, the amount of charge that can be sufficiently used for the image forming apparatus was confirmed, so that there was not much difference between the embodiments and almost no difference depending on the position.
[0066]
Next, an example of the process cartridge according to the present invention including the developing device according to the present invention will be described with reference to FIG.
The process cartridge 200 processes a plurality of components including at least the developing unit 203 among components such as the image carrier 201, the charging unit 202, the developing unit 203 which is the developing device according to the present invention, and the cleaning device 204. The cartridge is integrally connected as a cartridge, and the process cartridge is detachable from a main body of an image forming apparatus such as a copying machine or a printer.
[0067]
Usually, since a color image forming apparatus has a plurality of image forming units, the apparatus becomes large. Further, when each unit such as the developing device, cleaning, charging, etc. fails individually or it is time to replace it due to its life, the apparatus is complicated and it takes much time to replace the unit.
[0068]
Therefore, by forming a plurality of constituent elements including at least the developing means integrally as the process cartridge 200, a small and highly durable color image forming apparatus that can be replaced by the user can be provided.
[0069]
Next, an example of an image forming apparatus including a plurality of process cartridges according to the present invention will be described with reference to FIG.
In this image forming apparatus, the above-described process cartridges 200Y, 200M, 200C, and 200Bk (hereinafter also collectively referred to as “process cartridges 260”) along the transfer belt (image carrier) 251 extending vertically. Is a color image forming apparatus in which are arranged in the vertical direction. The process cartridge 200 has been described in the order of yellow, magenta, cyan, and black. However, the process cartridge 200 is not specified in this order, and may be arranged in any order.
[0070]
Here, the development toner on the image carrier 201 developed with the process cartridges 200Y, 200M, 200C, and 200Bk for each color is sequentially transferred to the transfer belt 251 to which a transfer voltage extending in the vertical direction is applied.
[0071]
In this way, images of yellow, magenta, cyan, and black are formed, transferred onto the transfer belt 251 in multiple layers, and transferred onto the transfer material 253 by the transfer unit 252. The multiple toner images on the transfer material 253 are fixed by a fixing device (not shown).
[0072]
As described above, since the process cartridge and the image forming apparatus according to the present invention include the developing device according to the present invention, high quality development can be performed and high quality images can be formed.
[0073]
【The invention's effect】
As described above, according to the developing device of the present invention, Placed in the stirring tank An agitation means for agitating the developer and a toner that conveys the toner to the development area by a traveling wave electric field -Carrying Between the feeding means, the stirring means and the toner conveying means. The bottom of the stirring tank The mesh electrode placed on the , Have Apply the same charge voltage as the toner to the mesh electrode Since it was set as the structure, the developing device excellent in stirring conveyance property is obtained.
[0074]
According to the process cartridge according to the present invention, since the developing device according to the present invention is provided, a process cartridge which is excellent in developer agitation transportability and capable of forming a high quality image is obtained.
[0075]
Since the image forming apparatus according to the present invention includes the developing device or the process cartridge according to the present invention, a high-quality image can be formed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a portion of a developing device according to the present invention of an image forming apparatus according to a first embodiment of the present invention.
FIG. 2 is an explanatory plan view of the developing device.
FIG. 3 is an explanatory diagram of a developer stirring and conveying screw of the developing device.
FIG. 4 is a schematic configuration diagram of a part of a developing device according to the present invention of an image forming apparatus according to a second embodiment of the present invention.
FIG. 5 is a perspective explanatory view of a stirring member of the developing device.
FIG. 6 is an explanatory diagram of a stirring fin of the stirring member
FIG. 7 is an explanatory diagram of a rib of the stirring member
FIG. 8 is a schematic configuration diagram of a part of a developing device according to the present invention of an image forming apparatus according to a fourth embodiment of the present invention.
FIG. 9 is an explanatory diagram for explaining a fur brush and a mesh electrode of the developing device.
FIG. 10 is an explanatory view of a stirring fin of a stirring member according to a fifth embodiment of the present invention.
FIG. 11 is also an explanatory diagram of ribs
FIG. 12 is a schematic cross-sectional explanatory view of a stirring fin.
FIG. 13 is an explanatory diagram of a test apparatus for explaining the operation of the developing device according to the present invention.
FIG. 14 is an explanatory diagram showing the measurement results of the relationship between the stirring time and the charge amount at each measurement point in FIG. 13 of the developing device according to the first embodiment.
FIG. 15 is an explanatory view showing the measurement results of the relationship between the stirring time and the charge amount at each measurement point in FIG. 13 of the developing device according to the second embodiment.
FIG. 16 is an explanatory view showing the measurement result of the relationship between the stirring time and the charge amount at each measurement point in FIG. 13 of the developing device according to the fourth embodiment.
FIG. 17 is a schematic configuration diagram of a process cartridge according to the present invention.
FIG. 18 is a schematic configuration diagram illustrating another example of an image forming apparatus according to the present invention.
FIG. 19 is an explanatory diagram of a stirring and conveying screw used in a conventional developing device.
FIG. 20 is an explanatory diagram of another stirring and conveying screw used in a conventional developing device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Image carrier, 2 ... Developing apparatus, 11 ... Toner supply part, 12 ... Toner electrostatic conveyance means, 21 ... Developing container, 22 ... Toner hopper part, 23 ... Stirrer tank, 27 ... Developer stirring conveyance screw, 28 ... Mesh electrode, 42a to 42c ... conveying electrode, 57 ... stirring member, 62 ... stirring fin, 63 ... rib, 65,66 ... triangular projection, 200, 201M, 201C, 201Y, 201B ... process cartridge, 203 ... development means.

Claims (13)

In a developing device for developing an electrostatic latent image formed on an image carrier with a two-component developer containing toner and carrier,
A stirring means disposed in the stirring tank for stirring the developer;
A toner over conveyance means for conveying at traveling wave electric field the toner to the developing area,
A mesh electrode disposed on the bottom of the stirring tank be between said conveying means and said stirring means comprises,
A developing device , wherein a voltage having the same charge as that of the toner is applied to the mesh electrode .   2. The developing device according to claim 1, wherein the stirring means is a screw.   2. The developing device according to claim 1, wherein the agitation unit has a function of agitating and charging the developer by arranging a plurality of flat plate-like members on the peripheral surface of the main shaft at different positions in the axial direction. A developing device.   4. The developing device according to claim 3, wherein a triangular protrusion is formed on a surface of the flat plate member of the stirring means.   5. The developing device according to claim 3, wherein a plurality of rib members are provided at different positions in the axial direction on a portion of the stirring unit where the main plate is not provided with a flat plate member, and a triangular surface is provided on the surface of the rib member. A developing device characterized in that a protruding portion is formed.   6. The developing device according to claim 3, wherein the stirring means stirs the developer by a butterfly method or a pendulum method.   The developing device according to claim 1, wherein the stirring means has a brush structure.   The developing device according to claim 7, wherein the stirring unit is in contact with the mesh electrode.   8. The developing device according to claim 1, wherein a charging functional material is formed on a surface of the stirring unit.   10. The developing device according to claim 1, wherein a charging functional material is formed on an inner surface of a stirring tank in which the stirring unit is disposed.   The developing device according to claim 1, wherein at least one of an image carrier, a charging unit, a transfer unit, and a cleaning unit and a developing unit are included in the process cartridge that is detachable from the main body of the image forming apparatus. A process cartridge characterized by being an apparatus.   11. The developing device according to claim 1, wherein the electrostatic latent image formed on the carrier is developed with a two-component developer including toner and carrier to form an image. An image forming apparatus comprising the process cartridge according to claim 11.   An image forming apparatus for forming a color image, comprising a plurality of process cartridges according to claim 11.

Images