JP4019490B2 - Development device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of developing devices used in image forming apparatuses such as laser printers and laser facsimiles that form images by electrophotographic technology.
[0002]
[Prior art]
Conventionally, as this type of technology, for example, in an image forming apparatus having a plurality of developing cartridges having a detachable toner cartridge, a developer carrier, a supply roller, a developer thinning means, and a detachable toner cartridge. In some development cartridges, the toner cartridge can be replaced, and the capacity of the black toner cartridge is larger than that of the other toner cartridges.
[0003]
According to this prior art, the toner is less deteriorated compared to the case where toner for the life of the developer carrying member, the supply roller, and the toner thin layer means is put in the developing cartridge at one time, and it is uniform and stable until the end. An image can be obtained, and the cost can be reduced as compared with the case where the entire developing cartridge is replaced.
[0004]
Further, Japanese Patent Application Laid-Open No. 63-139379 (Known Example 1) describes a fur brush 31 made of an elastic material that stirs toner and conveys it to a developing roller. Japanese Patent No. 340571 (Known Example 2) describes a developing device 3 in which a plurality of toner stirring members 7 are provided.
[0005]
[Problems to be solved by the invention]
The toner can be easily replenished by the above-described prior art and known examples, but there is still room for improvement.
[0006]
That is, the prior art is related to the toner cartridge replacement technique, and the toner agitating and conveying means in the known examples 1 and 2 are merely supplied to the developing roller without solidifying the toner. However, it has not always been guaranteed that the agitation / conveyance means itself can maintain the required constant speed rotation with the required torque, and the toner can be conveyed without unevenness.
[0007]
A first problem to be solved by the present invention is to provide an image that can prevent image deterioration due to torque fluctuation in an agitator.
[0008]
The second problem to be solved by the present invention is to provide an apparatus capable of preventing the agitator from stopping and obtaining a high-quality image.
[0009]
A third problem to be solved by the present invention is to provide a fin that can be prevented from causing unevenness in image density by preventing the development cartridge from vibrating by sliding the fin against the partition wall. .
[0010]
A fourth problem to be solved by the present invention is to provide a simple structure that can supply toner smoothly.
[0011]
[Means for Solving the Problems]
As means for solving the above-described problems in the present invention, the following means are provided.
[0012]
(1) and the developer carrying member, the developing device including a feed roller, a developer tank, the developing cart Riddji having a plurality of agitator having fins rubbing a developer tank inner wall, adjacent in the developer tank The first and second main hoppers are semi-cylindrical, and the partition wall between the two main hoppers, which becomes the rubbing start point with the fins of the agitator, is arranged at a high position of the wave front, and the parallel shape first, a second ridge portion, and a third ridge portion perpendicular with form and curvature-like chamfered shape thereto, and Na a shape deviating the wavefront shape of the top portion to the developer feeding direction upstream side A developing device.
[0013]
According to the above-mentioned corresponding means, the swirling agitator fins softly abut against the partition wall without impact, and can effectively transport the toner while rubbing, during which the agitator rotation is hindered. It does not occur and does not cause vibration in the developing cartridge, and can provide a high-quality image.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0015]
FIG. 2 is a schematic diagram showing an example of an image forming apparatus 1000 using the developing unit 400 according to the present invention.
[0016]
Hereinafter, the outline of the image forming apparatus 1000 will be described, and then the developing cartridge 410 will be described in detail.
[0017]
The image forming apparatus 1000 is an apparatus that can form a full-color image using a developer using four color developers of yellow, cyan, magenta, and black (hereinafter, toner is used as an example, and hence toner T). is there.
[0018]
In FIG. 2, reference numeral 1100 denotes an outer box of the apparatus, and an exposure unit 100, a paper feeding unit 200, a photosensitive cartridge 300, a developing unit 400, an intermediate transfer unit 500, a fixing unit 600 and the like are provided in the outer box 1100. Yes.
[0019]
The photosensitive cartridge 300 includes a latent image carrier 310, a charging roller 320 as a charging unit that contacts the outer peripheral surface of the latent image carrier 310 and uniformly charges the outer peripheral surface, and a cleaner unit 330. ing.
[0020]
The developing unit 400 includes a developing cartridge 410Y for yellow, a developing cartridge 410C for cyan, a developing cartridge 410M for magenta, and a developing cartridge 410K for black.
[0021]
Each of these developing cartridges 410Y, 410C, 410M, and 410K contains toners of yellow, cyan, magenta, and black, respectively.
[0022]
Further, developer carriers 430Y, 430C, 430M, and 430K are provided, respectively, so that only the developer carrier of any one development cartridge can come into contact with the latent image carrier 310.
[0023]
The intermediate transfer unit 500 includes a medium driving roller 510, a scavenging roller 520, a tension roller 530, a secondary transfer roller 540, an intermediate transfer belt 550 stretched around these rollers, and the intermediate transfer belt 550. And a medium cleaner 560 capable of contacting and separating.
[0024]
A backup roller 570 is disposed opposite to the secondary transfer roller 540.
[0025]
The medium drive roller 510 is rotationally driven by transmission means (not shown) at substantially the same peripheral speed as that of the latent image carrier 310, so that the intermediate transfer belt 550 is circulated and driven at substantially the same peripheral speed as that of the latent image carrier 310. It has come to be.
[0026]
The toner image on the latent image carrier 310 is transferred onto the intermediate transfer belt 550 while the intermediate transfer belt 550 is circulated, and the toner image transferred onto the intermediate transfer belt 550 is transferred to the secondary transfer roller 540. Are transferred to a recording sheet S such as a sheet supplied from the sheet feeding unit 200.
[0027]
The sheet feeding unit 200 includes a tray 210 on which recording sheets S are stacked, a pickup roller 220, and a separation roller 230 that reliably separates the sheets fed by the pickup roller 220 one by one. ing.
[0028]
The recording sheet S fed by the paper feeding unit 200 is supplied between the intermediate transfer belt 550 and the secondary transfer roller 540 by the transport roller 240 and subjected to transfer processing, and is subjected to fixing processing by the fixing unit 600, and the paper transport roller 250. More discharged.
[0029]
The fixing unit 600 includes a fixing roller 610 having a heat source and a pressure roller 620 pressed against the fixing roller 610.
[0030]
The operation of the image forming apparatus 1000 as described above is as follows.
[0031]
(1) When a print command signal (image formation signal) is input from a host computer (not shown), the latent image carrier 310 and the intermediate transfer belt 550 are driven to rotate.
[0032]
(2) The outer peripheral surface of the latent image carrier 310 is uniformly charged by the charging roller 320.
[0033]
{Circle around (3)} The exposure unit 100 exposes the outer peripheral surface of the uniformly charged latent image carrier 310 according to the first color (for example, yellow) image information to form a yellow electrostatic latent image.
[0034]
(4) The developer carrying member 430Y of the developing cartridge 410Y for the first color (for example, yellow) starts to rotate and simultaneously contacts the latent image carrying member 310, whereby the electrostatic latent image is developed, and the first color is developed. A toner image (for example, yellow) is formed on the latent image carrier 310, and the developer carrier 430Y of the development cartridge 410Y for the first color is separated from the latent image carrier 310 and stops rotating.
[0035]
(5) The toner image formed on the latent image carrier 310 is transferred from the latent image carrier 310 onto the intermediate transfer belt 550.
[0036]
(6) The toner remaining on the latent image carrier 310 is removed by the cleaner blade 331 of the cleaner unit 330 and then collected by the waste toner screw 332.
[0037]
(7) The second color, the third color, and the fourth color are repeated according to the contents of the print command signal, and toner images according to the contents of the print command signal are superimposed on the intermediate transfer belt 550. The above operations (2) to (6) are repeated.
[0038]
(8) The recording sheet S is supplied from the paper feeding unit 200 at a predetermined timing, and when the leading edge of the recording sheet S reaches the secondary transfer roller 540, the toner image on the intermediate transfer belt 550 is transferred onto the recording sheet S. .
[0039]
(9) When the recording sheet S passes through the fixing unit 600, the toner image is fixed on the recording sheet S, and the recording sheet S is discharged out of the case 1100 through the paper conveyance roller 250.
[0040]
The outline of the image forming apparatus 1000 has been described above. Next, the developing unit 400 and the developing cartridge 410 will be described.
[0041]
The developing unit 400 includes four developing cartridges 410 (Y, C, M, and K) that are detachably incorporated.
[0042]
Note that an arbitrary developing cartridge 410 in the outer box 1100 can be attached and detached, and the photosensitive member cartridge 300 can also be attached and detached.
[0043]
FIG. 3 is an enlarged view of the development cartridge 410M.
[0044]
The four developing cartridges 410 (Y, C, M, and K) are slightly different in shape and the like, but the basic structure is common, so that the developing cartridge 410M for magenta is represented. An embodiment will be described.
[0045]
The development cartridge 410 includes a case 420, a developer carrier 430 that supplies the toner T stored in the case 420 to the surface of the latent image carrier 310, and a supply that supplies the toner T to the developer carrier 430. A roller 440, an agitator 451, 452 having two transfer fins 461, 462 for transferring toner T toward the supply roller 440, a toner cartridge 470 that can replenish the toner T, and the developer carrier 430. And a thin layering unit 480 that controls the amount of toner on the developer carrier 430.
[0046]
The toner cartridge 470 has a cylindrical shape with inner and outer cases 472 and 473 fitted with an elastic member 471 so as to be relatively displaceable. The toner T can be supplied by aligning the through holes 474 and 475.
[0047]
A handle 476 protrudes from the inner case 472 and turns the inner case 472.
[0048]
Reference numeral 477 denotes an agitator, which is provided with fins 478, which prevents the toner T from coagulating and supports its supply.
[0049]
The developer carrier 430 is rotatably supported by the case 420, and a supply roller 440 that is parallel to the developer carrier 430 and whose surfaces are in pressure contact with each other is also rotatably supported by the case 420. .
[0050]
The toner T thinning means 480 is supported in a cantilever manner on the receiving member 481, and the blade 482 is brought into contact with the developer carrier 430.
[0051]
The case 420 is provided with a substantially semi-cylindrical row of toner tanks 421 and is held in a wedge-shaped space formed by sliding the fins 461 and 462 of the rotating agitators 451 and 452 in sliding contact with the inner surface 421a of the toner tank 421. In this way, the toner T is transferred.
[0052]
The fins 461 and 462 are formed in a thin plate shape having flexibility, and when the toner tank 421 is suddenly displaced and released in the vicinity of the supply roller 440, the toner T is transferred so as to be held in the wedge-shaped space. The toner is transferred to the surface of the supply roller by a mechanical conveying force so as to be repelled by the restoring force due to the elasticity of 461 and 462.
[0053]
The rotational loads of the agitators 451, 452, and 477 are made uniform by differentiating their rotational phases. When n toner transfer means are connected in series (n = 3 in this case), n transfer means. By shifting the angles of the fins 461, 462, and 478 by 360 ° / n, the sliding contact lengths of the fins 461, 462, and 478 rotating in contact with the inner surface 421a are substantially constant regardless of the angles of the agitators 451, 452, and 477. And
[0054]
Since the load fluctuations before and after the toner T is bounced by the agitators 451, 452, and 477 are dispersed, even in a high density toner having poor fluidity, the loads by the agitators 451, 452, and 477 are equalized, and the torque fluctuations of the apparatus are reduced. It can be reduced.
[0055]
The case 420 is detachably attached on the mounting table 1200.
[0056]
In the developing cartridge 410 configured as described above, the toner cartridge 470 is loaded, the inner case 472 is swung open by the handle 476, and the toner T is swung in the agitator 452, 451 direction by the swirled agitator 477. The toner is transferred and supplied to the developer carrier 430 through the supply roller 440 that is driven to rotate, and is attached to the latent image carrier 310.
[0057]
1 and 3, the toner tank 421 includes a sub hopper 421A in which a developer carrier 430 and a supply roller 440 are disposed, and first and second main hoppers 421B in which agitators 451 and 452 are disposed. 421C is provided, and the vertical cross-sectional shape of the toner tank 421 is such that the sub hopper 421A is flat in the direction of the latent image carrier 310 and is erected in an arc shape in the direction of the first main hopper 421B. The first main hopper 421B and the second main hopper 421C are both semi-cylindrical and generally have a wave shape.
[0058]
Further, the first partition wall 422B between the first and second main hoppers 421B and 421C is arranged at a so-called wavefront-like high position, and the external shape thereof is as shown in FIGS. The first ridge line portion L1 and the second ridge line portion L2 parallel to the third ridge line portion L3 and the third ridge line portion L3 perpendicular thereto are, for example, a chamfered shape with a curvature of 0.5 mm to 5 mm, preferably about 2 mm. It is a thing.
[0059]
Accordingly, when the toner T is transported by the agitator 451 that is swung in the direction of the arrow, the fin 461 softly abuts on the surface of the protrusion 421D having a chamfered shape without giving a sudden impact, and the toner T The drive torque of the agitator 451 gradually increases, suppresses sudden torque fluctuations, and minimizes the influence on the motor, thereby degrading the image. Can be prevented.
[0060]
Further, it is possible to reduce the impact when the fins 461 are rubbed against the inner surface 421a of the toner tank 421 and bend, thereby preventing the developing cartridge 410 from vibrating and preventing the deterioration of the image such as density unevenness.
[0061]
Further, it is possible to prevent the rotation of the agitator 451 from being stopped due to a sudden increase in torque due to the fin 461 getting caught at the rubbing start point with the inner surface 421a.
[0062]
Further, it is possible to prevent the agitator 451 from rotating in the reverse direction due to the elastic reaction force of the fin 461 when the fin 461 is constrained by the rubbing start point with the inner surface 421a.
[0063]
If the curvature of the chamfered shape is 1.0 mm or more, the friction is small and the drive torque does not fluctuate or increase. Also, since the curvature is sufficiently large, the deterioration due to the pressure friction of the toner T is reduced. Then, the toner T is smoothly conveyed without the partition wall 422B accumulating, and a preferable result is obtained.
[0064]
The above chamfered shape is also applied to the partition wall 422B between the main hoppers 421B and 421C, the toner cartridge 470, and the main hoppers 421B and 421C, so that the rotation of the agitator 452 is as smooth as the rotation of the agitator 451.
[0065]
Similarly, the development cartridge 410 as described above is detachably attached to the outer box 1100 in a total of four as yellow 410Y, cyan 410C, magenta 410M, and black 410K. Since the function is the same as that of the above-described magenta 410M, repeated description is omitted.
[0066]
【The invention's effect】
The specific effects of the present invention described above are as follows.
[0067]
{Circle around (1)} It is possible to prevent image deterioration due to toner supply failure due to sudden stop of the agitator or uneven rotation.
[0068]
{Circle around (2)} The fins slide and rub on the inner surface of the toner tank, and there is no possibility that the developing cartridge vibrates, and the toner can be effectively supplied to obtain an excellent image without image unevenness.
[0069]
(3) It is possible to obtain a simple structure that does not cause a failure.
[Brief description of the drawings]
FIG. 1 is an enlarged sectional view of a main part in an embodiment of the present invention.
FIG. 2 is a schematic diagram of an image forming apparatus equipped with the developing cartridge of the present invention.
FIG. 3 is a partial cross-sectional view of the developing cartridge of the present invention.
4 is a partial perspective view of the partition wall of FIG. 3;
FIG. 5 is a plan view of FIG. 4;
[Explanation of symbols]
310 Latent image carrier 410 Developing cartridge 420 Toner cartridge 421 Toner tank 421A Sub tank 421 (B, C) Main tank (first, second)
422B Partition wall 430 Developer carrier 440 Supply roller

Claims (1)

A developer bearing member, a feed roller, a developer tank, the developing device including a developing cart Riddji having a plurality of agitator having fins rubbing a developer tank inner wall, the adjacent shaped in the developer tank 1. The second main hopper has a semi-cylindrical shape, and a partition wall between the two main hoppers which becomes a rubbing start point with the fin of the agitator is arranged at a high position of the wave front, and the parallel first , wherein the second ridge portion, and a third ridge portion perpendicular with form and curvature-like chamfered shape thereto, that it has name and shape deviating the wavefront shape of the top portion to the developer feeding direction upstream side A developing device.

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