JP3887937B2 - 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 a technique for preventing toner leakage in this type of developing device, for example, Japanese Patent Laid-Open No. 4-80390 (known example 1) is disclosed, and examples of supporting means for the developing roller and the supply roller are disclosed. JP-A-3-249780 (known example 2) is known.
[0003]
In the known example 1, the developing roller 35 and the elastic blade 36 that comes into contact with the developing roller 35 are disposed on the side frames 32 and 33 with the elastic member 50 interposed therebetween. In the known example 2, the shaft portion of the developing roller 22 is rotatably mounted on the positioning blades 31a and 31b by a bearing 33.
[0004]
Further, as a prior art, there is a technique in which a shaft portion of a developer carrier and a supply roller is rotatably supported by a single bearing (prior art).
[0005]
[Problems to be solved by the invention]
The toner can be easily replenished by the above-described known examples and the prior art, but there is still room for improvement.
[0006]
That is, in the above-mentioned known example 1, since the elastic body 50 is merely interposed, the toner leaks from the side surface of the contact portion between the developing roller 35 and the elastic blade 36 in particular. There was a risk of lowering the image quality.
[0007]
Further, in the case of the known example 2, since the sealing means is not provided on the side surfaces of the developing roller and the supply roller, the toner leaks and it is difficult to expect to develop a high quality image. In the prior art, for example, since the distance between the developer carrying member and the supply roller is determined by the bearing, the biting depth between the developer carrying member and the supply roller is kept constant, and the density during development is reduced. It is possible to obtain a uniform image without uneven density, and when the developer carrier and the supply roller are driven, the developer carrier and the supply roller are separated by a reaction force, and the nip between the two is larger than a predetermined amount. Although there are advantages such as avoiding the danger of being reduced, there remains anxiety in that it can be driven with low torque and can stably prevent toner leakage.
[0008]
A first problem to be solved by the present invention is to provide a developer carrier that can safely prevent leakage of toner on the side surfaces of the blades of the thinning means.
[0009]
A second problem to be solved by the present invention is to provide a toner that can prevent toner from entering between the developer carrying member and the elastic member.
[0010]
A third problem to be solved by the present invention is to provide a device that can be smoothly driven with light torque.
[0011]
A fourth problem to be solved by the present invention is to provide a toner that can prevent toner leakage without being affected by a surrounding temperature change such as a temperature change.
[0012]
A fifth problem to be solved by the present invention is to provide a simple structure and easy assembly.
[0013]
The sixth problem to be solved by the present invention is to provide a presser that can be safely locked.
[0014]
[Means for Solving the Problems]
As means for solving the above-described problems in the present invention, the following means are provided.
[0015]
(1) A developing device in which a developer carrying member is rotatably attached to a case of a developing cartridge, and each support shaft of the developer carrying member is rotatably supported by a bearing attached to the case, and a developer. A developer thinning means having a blade abutting on the carrier is provided, and an elastic member interposed between the developer carrier, each side surface of the blade and the case is brought into contact with the developer carrier and the blade. In the position and its peripheral area, a pressing means for urging the elastic member interposed between the developer carrier, each side surface of the blade and the case in the direction of the developer carrier is disposed, and the pressing means is provided on the bearing. A developing device characterized in that it is a formed inward thrust .
[0016]
(2) A developing device in which a developer carrying member is rotatably mounted on a case of the developing cartridge, and each support shaft of the developer carrying member is rotatably supported by a bearing attached to the case, and the developer A developer thinning means having a blade abutting on the carrier is provided, and an elastic member interposed between the developer carrier, each side surface of the blade and the case is brought into contact with the developer carrier and the blade. In the position and its peripheral region, a pressing means for urging an elastic member interposed between the developer carrier, each side surface of the blade and the case in the direction of the developer carrier is provided, and the pressing means is attached to the case. A developing device which is a pressing element inserted and supported by the bearing so as not to be removed .
[0018]
According to the above-mentioned corresponding means, it is possible to safely prevent the leakage of toner in the vicinity of the contact position between the developing carrier and the thinning means only by pressing the elastic member locally inward.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0020]
FIG. 3 is a schematic view showing an example of an image forming apparatus 1000 using the developing unit 400 according to the present invention.
[0021]
Hereinafter, the outline of the image forming apparatus 1000 will be described, and then the developing cartridge 410 will be described in detail.
[0022]
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.
[0023]
In FIG. 3, reference numeral 1100 denotes an outer box of the apparatus. In this outer box 1100, 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. Yes.
[0024]
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.
[0025]
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.
[0026]
Each of these developing cartridges 410Y, 410C, 410M, and 410K contains toners of yellow, cyan, magenta, and black, respectively.
[0027]
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.
[0028]
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.
[0029]
A backup roller 570 is disposed opposite to the secondary transfer roller 540.
[0030]
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.
[0031]
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.
[0032]
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.
[0033]
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.
[0034]
The fixing unit 600 includes a fixing roller 610 having a heat source and a pressure roller 620 pressed against the fixing roller 610.
[0035]
The operation of the image forming apparatus 1000 as described above is as follows.
[0036]
(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.
[0037]
(2) The outer peripheral surface of the latent image carrier 310 is uniformly charged by the charging roller 320.
[0038]
{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.
[0039]
(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 first color development cartridge 410Y is separated from the latent image carrier 310 and stops rotating.
[0040]
(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.
[0041]
(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.
[0042]
(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.
[0043]
(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. .
[0044]
(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.
[0045]
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.
[0046]
The developing unit 400 includes four developing cartridges 410 (Y, C, M, and K) that are detachably incorporated.
[0047]
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.
[0048]
FIG. 4 is an enlarged cross-sectional view of the development cartridge 410M.
[0049]
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.
[0050]
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.
[0051]
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.
[0052]
A handle 476 protrudes from the inner case 472 and turns the inner case 472.
[0053]
Reference numeral 477 denotes an agitator, which is provided with fins 478, which prevents the toner T from coagulating and supports its supply.
[0054]
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. .
[0055]
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.
[0056]
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.
[0057]
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.
[0058]
For the agitators 451 and 452 and the agitator 477 in the toner cartridge 470, the rotational phases thereof are made different to equalize the rotational load. When n toner transfer means are connected in series (n = 3 in this case) ), By shifting the angle of the fins 461, 462, and 478 of the n transfer means by 360 ° / n, the sliding contact lengths of the fins 461, 462, and 478 rotating in sliding contact with the inner surface 421a are set to the agitators 451, 452, 477. It is almost constant regardless of the angle.
[0059]
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.
[0060]
The case 420 is detachably attached on the mounting table 1200.
[0061]
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.
[0062]
By the way, as shown in FIG. 1, the latent image carrier 310 is brought into contact with the support shaft 431 protruding outward of the flanged bearing 492 attached to the stepped hole 422 opened in the side wall 423 of the case 420. The positioning member 435 is loosely fitted in a rotatable state, and spring clips 493A and 493B as drop-off preventing means are engaged with the pair of reduced diameter portions 432A and 432B on the support shaft 431 on both sides thereof. ing.
[0063]
Further, an elastic member made of a sponge, rubber or the like is compactly formed between the inner surface 423 ′ of the side wall 423 of the case 420 and the side surface 430 ′ of the developer carrier 430 and the side surface 482 ′ of the blade 482 of the thinning means 480. 491 is interposed.
[0064]
(Embodiment 1)
Hereinafter, embodiments of the elastic member pressing means will be described.
[0065]
A flange 492P that protrudes inward is integrally formed on the flange portion 492F of the bearing 492. As shown in FIG. 1, the protrusion 492P is inserted into the through hole 424 of the side wall 423, and the inner end thereof is developed. Assembling is performed so as to protrude somewhat to the inside of the side wall 423 so as to be positioned in the vicinity of the contact position between the agent carrier 430 and the blade 482.
[0066]
Accordingly, the protrusion 492P is configured in a state in which the elastic member 492 is strongly urged inward in the vicinity of the contact position.
[0067]
Accordingly, during the developing process, the elastic member 491 is pressed against the contact region of the side surfaces 430 ′ and 482 ′ with high pressure near the contact portion between the developer carrier 430 and the blade 482 by the protrusion 492P. Thus, the sealing performance is improved, and the toner T can be completely prevented from entering between the developer carrier 430 and the elastic member 491.
[0068]
Further, it is possible to prevent the toner T from flowing into the side surface 430 ′ of the developer carrier 430 and spilling out in the vicinity of the development position on the latent image carrier 310, thereby preventing an image defect.
[0069]
Further, the relative positions of the developer carrier 430 and the blade 482 are shifted, and a gap that cannot be filled by the elastic member 491 is formed between the elastic member 491 and the developer carrier 430 and between the elastic member 491 and the blade 482, and the toner is formed from the gap. It is also possible to prevent T from spilling out.
[0070]
Further, since the elastic member 491 is partially pressed by the protrusion 492P, the elastic member 491 can be smoothly driven by a light torque, and the elastic member 491 can be prevented from being twisted.
[0071]
In addition, the difference in the axial length between the inside of the case 420 and the developer carrier 430 and the thinning means 482 is increased due to the difference in the thermal expansion coefficient due to the temperature change, and the inside of the case 420 and the developer carrier 430 are different. Even if the interval is increased, the toner T can be reliably sealed.
[0072]
When the convex portion is provided on the side wall 423 of the case 420, when the thinning means 480 is assembled, the elastic member 491 is compressed and incorporated, so that workability is lowered. The layering means 480 can be easily incorporated.
[0073]
By managing the mounting position of the bearing 492, the protruding state of the bump 492P can be controlled, so that the position accuracy can be improved, and as a result, the bump 492P can be reduced in size and torque can be reduced.
[0074]
The structure is simple and the cost can be reduced.
[0075]
(Embodiment 2)
The embodiment shown in FIG. 2 is different from that shown in FIG. 1 in that a through hole 422 ′ is further formed in the stepped hole 422 of the side wall 423, and a head-like pressing is applied to the through hole 422 ′. A child 492P ′ is mounted, and the headed pusher 492P ′ is pressed inwardly on the inner surface of the flange portion 492F of the bearing 492, and the thruster 492P of the first embodiment is fixed. It can be said that it is a separate body from the bearing 492.
[0076]
According to this pressing means, the assembly of the head-shaped pressing element 492P ′ is easy.
[0077]
Further, the head-like presser 492P ′ is engaged with the side wall 423 together with the bearing 492, so that no special retaining means is required and the structure can be simplified.
[0078]
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.
[0079]
【The invention's effect】
The specific effects of the present invention described above are as follows.
[0080]
{Circle around (1)} There is no possibility of toner entering between the developer carrying member and the elastic member.
[0081]
(2) The developer carrying member can be smoothly driven with light torque (claims 1 and 2).
[0082]
(3) Toner leakage can be stably prevented without being affected by temperature changes.
[0083]
(4) Assembly is easy (claims 1 and 2).
[0084]
(5) A special retaining means for the pressing member with a head is not required.
[Brief description of the drawings]
FIG. 1 is an enlarged cross-sectional view of a main part in Embodiment 1 of the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part in Embodiment 2 of the present invention.
FIG. 3 is a schematic diagram of an image forming apparatus equipped with the developing cartridge of the present invention.
FIG. 4 is an enlarged cross-sectional view of a developing cartridge according to the present invention.
[Explanation of symbols]
410 Developing cartridge 420 Case 423 Side wall 430 Developer carrier 430 'Side surface 440 Supply roller 480 Thinning means 482 Blade 491 Elastic member 492 Bearing 492P Rushing (pressing means)
492P 'presser (pressing means)

Claims (2)

A developing device in which a developer carrier is rotatably mounted on a case of a developing cartridge, and each support shaft of the developer carrier is rotatably supported by a bearing mounted on the case, and the developer carrier is attached to the developer carrier. A developer thinning means having a blade to be contacted is provided, and an elastic member interposed between the developer carrier, each side surface of the blade, and the case, and a contact position between the developer carrier and the blade In the peripheral region, a pressing means for urging an elastic member interposed between the developer carrier, each side surface of the blade and the case in the direction of the developer carrier is provided , and the pressing means is formed on the bearing. A developing device characterized in that it is a thrust in the direction . A developing device in which a developer carrier is rotatably mounted on a case of a developing cartridge, and each support shaft of the developer carrier is rotatably supported by a bearing mounted on the case, and the developer carrier is attached to the developer carrier. A developer thinning means having a blade to be contacted is provided, and an elastic member interposed between the developer carrier, each side surface of the blade, and the case, and a contact position between the developer carrier and the blade In the peripheral region, a pressing means for urging an elastic member interposed between the developer carrying body and each side surface of the blade and the case is disposed in the direction of the developer carrying body, and the pressing means is inserted into the case. A developing device, wherein the developing device is supported by the bearing so as not to be removed .

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