JPH03102377A - Developing device - Google Patents

Abstract

PURPOSE:To accomplish a developing device excellent in density maintaining stability by leading a developer carried along the guide plane provided in a developer carrying path downstream of a developing area to an agitating means by an induction plane provided so that the developer crosses the end of the guide plane. CONSTITUTION:A developing roll 1 and the guide plane 11 with a prescribed gap therefrom are provided in the developer carrying path 6 downstream of the developing area and along the path 6. After the developer scraped away from the developing roll 1 is carried along the guide plane 11, the developer that is led and scraped away by the induction guide 12 provided so that the developer crosses the end of the guide plane 11 is carried to the agitating means 2. Consequently, density irregularities resulting from the phenomenon that the developer separating from the developing roll 1 resides around the developing roll 1, moves in the circumferential direction of the developing roll 1 and resticks to the developing roll 1 are prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention visualizes an electrostatic latent image formed on a latent image carrier using a two-component developer consisting of a toner and a magnetic carrier. It relates to a developing device.

[Prior Art J] Conventionally, as a developing device for developing an electrostatic latent image formed on a latent image carrier, various types of devices have been proposed depending on the type of developer used and the like.

Among these, as a developing device using a two-component developer consisting of toner and a magnetic carrier, a so-called magnetic brush developing method is often used.

This magnetic brush developer m@ is a device that captures magnetic carriers carrying toner by magnetic force and arranges them along lines of magnetic force, thereby causing the developer to stand up in the form of a brush and rub it on the latent image carrier using FM. As a specific device configuration, for example, the third
As shown in Figure 4, multiple magnetic poles M with different magnetic polarities and magnetic forces
A known example includes a developer carrier a (hereinafter referred to as a developing roll) consisting of a magnet member a1 in which magnets L, N2, S2, N3, and 81 are fixedly arranged, and a sleeve a2 that rotates around the magnet member a1. It is being In the developing device configured in this way, the magnet member a
The developer is attracted to the sleeve a2 according to the magnetic field formed between the mutually adjacent different magnetisms 82 and S2 of 1 to form a magnetic brush, and as the sleeve a2 rotates, the magnetic brush is submerged. The image is transported to a development area facing the image carrier.

Then, as the surface of the latent image carrier b is brushed with the magnetic brush, a developing bias voltage is applied between the developing port a and the latent image carrier b. The toner is attracted to the electrostatic latent image, and the electrostatic latent image is developed. On the other hand, the developer whose toner content has decreased after passing through the development area is transferred to the adjacent IIfi poles of the same magnetic field.
Sleeve a2 due to the repulsive magnetic field formed between 1 and N2
11 peeled off from the developing roll a and provided on the back side of the developing roll a.
3) After being mixed and agitated with the replenishment toner by means C, the toner is resupplied to the developing roll a.

Incidentally, in recent years, an image forming apparatus using a so-called overlapping development method has been proposed as a means for producing multicolored recorded images. Specifically, as shown in FIG. 35, a plurality of latent image forming means Bl are arranged around one latent image carrier.
, B2... and a plurality of developing means CI C2... are arranged alternately, and the electrostatic latent image formed by the first latent image forming means 81 is developed by the first developing means C1. At the same time, the electrostatic latent image formed by the second latent image forming means B2 is developed by the second developing means C2 to form a second visible image. The plurality of visible images obtained are transferred at once to a recording sheet E by a transfer means 0 to obtain a recorded image.

In an image forming apparatus using this superimposed development method, a multicolor recorded image can be obtained with one rotation of the latent image carrier, so a single color visible image is repeatedly transferred to the recording sheet multiple times. Compared to conventional multicolor image forming devices that produce 100% recorded images, the number of rotations of the latent image carrier required to form one image is reduced, making it possible to improve the image forming speed per hour. .

However, in configuring this multicolor image forming apparatus,
To use the conventional developing device shown in L as a developing means,
There were major issues that needed to be solved. In other words, in the overlapping development method, visible images are formed one after another on the latent image carrier, so the visible image formed in the previous developing device is rubbed by the magnetic brush directly installed in the subsequent developing device, resulting in image disturbance. The point is that this occurs.

As a means to solve this problem, from the viewpoint of weakening the abdominal rubbing force of the magnetic brush against the electrostatic latent image carrier, a measure has been proposed in which the filling amount of developer in the developing area is set to be low.

However, as mentioned above, in the magnetic brush in a conventional developing device, the magnetic brush is formed by arranging the carriers along the lines of magnetic force and restricting their movement. The probability that the toner carried on the carrier comes into contact with the latent image carrier is reduced, and a decrease in developing ability cannot be avoided.

Therefore, a new magnetic brush development method (hereinafter referred to as FX microtoning method) has been proposed, which focuses on the movement of carriers in the development region and is an improvement on the conventional magnetic brush development method. Specifically, we use carriers with smaller particle diameters than conventional magnetic carriers, or carriers with reduced magnetic permeability by dispersing magnetic powder in a resin binder, as well as developing rollers that act on the developing area. The magnetic field is characterized by a repulsive magnetic field that spreads in two directions at a predetermined angle.

According to this method, the binding force of the magnetic force acting on the carrier at the center of the development area is temporarily reduced due to the synergistic effect of the reduction of the carrier particles or the weakening of the magnetic permeability and the fall of the magnetic force at the center of the repulsive magnetic field. This weakens the carrier's freedom.

As a result, the chain state of carriers normally formed in the magnetic brush development method is broken, and the carriers holding toner in the development area come into contact with the latent image carrier individually in a free state, and the toner latent image carrier is Body contact rate increases. In this way, in the development area, the carrier is not strongly restrained by the development roll and moves freely, so development can be performed with high efficiency while keeping the amount of developer filling in the development area low, and the sliding force of the magnetic brush is reduced. We were able to solve the two contradictory issues of reduction and maintenance of developing ability.

[Problems to be Solved by the Invention] However, in implementing the above FX microtoning method, new problems have arisen due to the characteristics of the developer carrier.

First, because the particle size of the carrier is small, the developer tends to aggregate, resulting in extremely poor fluidity. In this regard, conventional developers have such good fluidity that by feeding the developer one after another into the transport path, the developer in the transport path can be replaced by the pressing force. However, when attempting to transport developer using the FX microtoning method in a similar manner, the developer may become lumps or stick to the corners of the transport path due to the applied pressing force, resulting in It is impossible to stock the developer sufficiently.

The second problem is that by reducing the particle size or magnetic permeability of the carrier, the developer aggregates around the developing roll due to the influence of the magnetic force of the developing roll, thereby deteriorating its fluidity.

This is because the carriers that are attracted to the developing roll and arranged in a chain cannot fully absorb the magnetic energy, and the bonding force also acts between adjacent chains. In conventional carriers, because the amount of magnetic energy absorbed is large, the bonding force between the chains is weak, and in this way, the developer is
No phenomenon of agglomeration around the tube was observed.

As described above, the developer used in the FX microtoning method has extremely poor fluidity due to the particle size and magnetic permeability of the carrier, and due to poor transportation and agitation within the developing device. This has the problem that density unevenness tends to occur in recorded images.

Furthermore, as mentioned above, this FX microtoning magnetic brush development method has been proposed as a means to solve the problems caused by the overlapping development method, but in an image forming apparatus that implements the overlapping development method, A plurality of latent image forming means, a plurality of developing means, and a plurality of developing means control the potential of the toner image before transfer or the potential of the photoconductor in order to collectively transfer the plurality of toner images formed on the photoconductor to the recording sheet. It is necessary to install many devices such as a discharge processing device (corotron, etc.) or a light source in a limited space around the latent image carrier, and in order to miniaturize the device, it is necessary to install individual developing means. The space for
If a layout is adopted in which the developing device is disposed in the horizontal direction of the latent image carrier, it is not possible to adopt a vertical structure layout in which the developing roll and the stirring means are placed one above the other. We have no choice but to adopt a horizontal structure layout in which are placed on the left and right sides. Therefore, within the developing device, it is necessary to move the developer horizontally in a planar manner, making it even more difficult to transport the developer with poor fluidity.

Therefore, in order to clarify the problems associated with using a developer with poor fluidity, the inventors of the present application filled a conventional developing device with a horizontal structure with a developer used in the FX microtoning method, and conducted an experimental operation. In addition to observing the flow of the developer, samples of the recorded images were taken and the density unevenness was observed.

As a result, we discovered several characteristics and problems of developer flow that cause density unevenness.

The first problem concerns peeling off the developer from the developing roll.

As shown in FIG.
Due to the repulsion magnetic field formed between the developer roll A and the developer roll A, the developer is separated from the developer roll A and flows toward the stirring means C (solid arrow in the figure), but due to its poor fluidity, it tends to stagnate around the developer hole A. Therefore, the stagnant developer jumps over the repulsive magnetic field and moves in the circumferential direction of the developing roll a shown by the broken line arrow, and is attracted to the developing aperture roller again by the magnetic field formed by the attraction pole N2 and the transport pole S2. In this case, density unevenness such as white spots occurs in the recorded image sample, and the white spot area expands each time sample collection is repeated, resulting in a developed image with a clearly reduced toner content. It was inferred that the agent was adsorbed to the developing roll.

The second issue concerns the flow of developer within the stirring means. The stirring means usually includes a plurality of screw augers (hereinafter referred to as augers) arranged parallel to the axial direction of the developing roll, and each auger is separated by a partition wall with openings formed at both ends. , an agitation passage communicating with both end regions of each auger is formed. In the stirring means configured as described above, the developer is transported by the transporting force of each auger in the direction parallel to the axial direction of the developing roll, while the developer is transported by the transporting force of each auger in the direction parallel to the axial direction of the developing roll, while the developer is transported by the flow between the augers communicated by the openings. Transportation is carried out using gender. Therefore, when a developer with poor fluidity is used, the transport of the developer is delayed between each auger, and there is a problem in that more developer tends to accumulate on the downstream side of the auger than on the upstream side in the stirring path. is occurring. In particular, if the above-mentioned deviation in the amount of accumulation occurs in the agitation path adjacent to the developing roll, the supply of developer to the developing roll will become uneven along the axial direction, and the recorded image sample in this state will Density unevenness was observed along the axial direction of the developing roll.

Furthermore, the third aspect relates to the developer conveying ability and stirring ability of the auger disposed within the stirring means. As shown in FIG. 37, the auger d presses, conveys and stirs the developer with a spiral blade e as the rotating shaft f rotates, but the conventional auger d
Since the spiral blade 0 stands approximately perpendicularly to the rotation axis f, the conveyance performance in the axial direction is good, but the conveyance performance or stirring performance in the direction perpendicular to the axial direction is not sufficient. I can't say that there is. Therefore, when a developer with poor fluidity is used, as mentioned in the second gfj problem above, not only does the conveyance of the developer between each auger tend to be delayed, but also the developer and replenishment toner tend to be delayed. A problem has arisen in that the adhesion between the toner and the toner is not sufficiently carried out, and some unevenness has occurred in recorded image samples due to poor replacement of the developer.

Furthermore, the fourth aspect relates to adsorption of the developer to the developing roll. The developer is attracted to the developing roll by the attractive magnetic field formed by the attracting pole and the transport pole, but due to the poor fluidity of the developer, it is difficult to uniformly attract the developer to the developing roll at all times. points are occurring. For this reason, the maintenance stability of image density was poor, and density unevenness without reproducibility was confirmed in recorded image samples taken repeatedly.

As is clear from the above facts, in developing devices that implement the FX microtoning method, the poor fluidity of the developer causes various problems due to density unevenness. When designing an applicable developing device, overcoming each problem based on the above-mentioned developer flow characteristics is an important issue in order to obtain good recorded images with no unevenness. I can say that.

In addition, although the problems of the two-component developer in the FX microtoning method have been explained here as an example, the problems are not limited to this, and can also be applied to other two-component developers or single-component developers.
Some developers have poor fluidity depending on various factors such as the particle size, magnetic permeability, and particle shape of the developer. Even in other developing devices that use such a developer with poor fluidity, density unevenness caused by the flow of the developer is an important issue that cannot be overlooked at the stage of commercializing the device.

The present invention has been made in view of these problems, and its main purpose is to provide a developing device that is applicable to the X microtoning developing method and has excellent density maintenance stability. That is.

More specifically, it is an object of the present invention to provide a developing device capable of overcoming the problems caused by the characteristics of developer flow described above and capable of obtaining good a-recorded images without density unevenness.

Furthermore, another object of the present invention is to provide a developing device that can obtain good recorded images not only with the developer used in the FX microtoning system but also with various intervening developers with poor fluidity. It is in.

[Means for Solving the Problems] In order to achieve the above object, the developing device d of the present invention is characterized by the following technical means.

First of all, the current 11l equipment according to claim 1 corresponds to the first problem. As mentioned above, the first problem is density unevenness caused by the developer peeled off from the developing roll becoming stagnant around the developing roll, moving in the circumferential direction of the developing roll, and being adsorbed to the developing roll again. It is. The inventors of the present application initially provided an obstacle near the outer peripheral surface of the developer carrier,
This prevents the developer after peeling from moving in the circumferential direction of the carrier, and prevents the toner from moving in the circumferential direction of the carrier. It was thought that it is possible to prevent the developer that has decreased even once from being reabsorbed by the carrier. Then, a developing device as shown in FIG. 2 was proposed. Specifically, a rod-shaped member 5 is arranged parallel to the axial direction of the developing roll 1 in a region (separation region) where a repulsive magnetic field formed by the stripping pole N1 and the attracting pole N2 acts. . According to this developing device, the peeled developer can be prevented from flowing in the circumferential direction of the developing hole 1, and the first problem described above can be solved.

However, the above proposal of arranging the rod-shaped members 5 requires consideration of the assembly effort due to the increase in the number of disposed members.
This cannot necessarily be said to be the best means for solving the above problems.

Therefore, as a result of further research, the inventors of the present application found that the reason why the developer stagnates in the peeling area is because the developer peeled off from the developing roll 1 generates a swirling flow near the developing roll 1. There was found.

Then, guide the developer so that this swirling flow does not occur.
It has been found that by guiding the developer, it is possible to prevent the developer from stagnation in the peeled area and to prevent the developer from being re-adsorbed onto the developing roll 1.

As a result, they came up with a developing device according to claim 1.

That is, as shown in FIG. 1, the development station according to claim 1 has a plurality of magnetic poles, attracts the developer according to the magnetic field formed between the magnetic poles, and also attracts the developer along a predetermined path including the development area. 6 a developer port 1 (developer carrier) that peels off the developer after conveying the developer along the developer conveyance path;
A developer conveyance path downstream of the development area includes a stirring means 2 that mixes and stirs the developer peeled off from the developer roll 1 and replenishment toner and supplies the stirred developer to the developer roll 1. 6 is provided with a guide surface 11 having a predetermined gap with the developing roll 1 along the conveying light path 6, and the developer peeled off from the developing roll 1 after being conveyed along the guiding surface 11 is A guiding surface 12 for guiding the stirring means 2 is provided so as to intersect with one end of the guiding surface 11.

In such technical means, the distance between the guide surface 11 and the developing roll 1 is such that the magnetic force of the developing port 1 is applied to the developer in the developer transport path 6 covered by both members. If so, you can change the design of the spacing as appropriate. This is to prevent the developer that is not affected by the magnetic force from stagnating in the transport path 6 due to poor fluidity.If the developer stagnates in the transport path G, the developing area This is because a situation may arise in which the developer that has passed through the developing device does not enter the developing device and overflows outside the device.

The position of the line of intersection between the guiding surface 11 and the guiding surface 12 varies depending on the ratio of the magnetic force between the peeling t4iN1 that forms a repulsive magnetic field and the attracting pole N2, or the fluidity of the developer. As long as the developer peeled off from the roll 1 flows toward the stirring means 2 along the guiding surface 12 without forming a swirling flow, the design of the crossing position may be changed as appropriate.

Further, a developing device according to a second aspect of the present invention corresponds to the above-mentioned second problem. The second problem, as mentioned above, is density unevenness caused by uneven developer deposition within the developer stirring path. We devised the following invention, believing that it is possible to eliminate the unevenness of the amount of developer deposited by adjusting the amount of developer flowing in and out of the developer stirring path in which the first auger is disposed. It's arrived.

That is, the developing device according to claim 2 has a plurality of magnetic poles, attracts the developer according to the magnetic field formed between each magnetic pole, and after conveying the developer along a predetermined path including the developing area. A developing roll 1 for peeling off the developer, and a first auger 21 capable of conveying the developer in the axial direction by rotation are provided behind the developing roll 1, and a partition plate 13 having openings formed at both ends allows the developer to be A stirring means having one or more augers 22 separated from the first auger 21, which mixes and stirs the developer peeled off from the developing roll 1 and replenishment toner, and supplies the developer after stirring to the developing roll 1. 2, of the openings provided at both ends of the partition plate 13, the opening width of the opening 14 located on the downstream side in the developer conveyance direction of the first auger 21 is A, and the opening width is A, and the opening width is A, and When the opening width of the opening 15 is 8, the opening width of the opening of the partition plate 13 is determined so as to satisfy the relationship A>8 (see FIG. 3).

In such technical means, the opening 1 of the partition plate 13
4.15 may be opened at any position as long as the developer can be supplied to the entire developable area C of the developing roll 1, but the developer is likely to accumulate in the opening. When considering the characteristics of the developer flow, it is preferable that the openings 14 and 15 of the partition plate 13 are opened outside the developable area C of the developing port 1, as in the developing device according to the third aspect.

Furthermore, a developing device according to a fourth aspect of the present invention also addresses the second problem. In the developing device according to the above M claims 2 and 3, the developer stirring path is improved to adjust the flow rate of the developer in the stirring path and to make the deposited matrix uniform. The described developing system attempts to eliminate the non-uniformity of developer deposition by conveying the developer between the respective augers in a top-to-bottom manner.

That is, the developing device according to claim 4 has a plurality of magnetic poles, attracts the developer according to the magnetic field formed between each magnetic pole, and after conveying the developer along a predetermined path including the developing area. A developing roll 1 for peeling off the developer and a first auger 21 capable of transporting the developer in the axial direction by rotation are placed behind the developing nozzle 1, and a partition plate with openings formed at both ends. It has one or more augers 22 separated from the first auger 21 by 13, and mixes and stirs the developer peeled off from the developing nozzle 1 and replenishment toner, and transfers the agitated developer to the developing nozzle. At least the first auger 21 is mounted on the rotation shaft 21a of the auger so as to face the opening 14 of the partition plate 13 located on the flow side in the developer conveying direction. Upright plate member 2
3 (see Fig. 4).

In such technical means, if the auger 21 is made of synthetic resin, the plate member 23 can be formed integrally with the rotating shaft 21a by injection molding, or it can be formed integrally with the rotating shaft 21a. The gold that wraps around the spiral blade 21b! In the case of an auger made of M, it is possible to manufacture it as a separate NS material and attach it by welding or wrapping.

Further, the plate-like member 23 does not need to be provided upright only on the first auger 21, and by providing it on all the augers, the circulation of the developer within the developing device can be made more reliable.

Furthermore, a developing device according to a fifth aspect of the present invention corresponds to the third problem. As mentioned above, the third problem is that the developer caused by the poor agitation and conveyance properties of the conventional A-ga developer.
In order to overcome the above problem, the inventors of the present application focused on the shape of the spiral blade of the auger and devised the following invention.

That is, the developing device according to claim 5 has a plurality of magnetic poles, attracts the developer according to the magnetic field formed between each magnetic pole, and conveys the developer along a predetermined path including the developing area. The developing roll 1 from which it will be peeled off later, and the rotating shaft 21a
, 22a, . . . spiral blades 21b, 22
b. It has one or more augers 21, 22, . . . which can transport the developer in the axial direction by .
Stirring means 2 for mixing and stirring the more exfoliated developer and replenishment toner and supplying the stirred developer to the developing roll 1
Each auger 21, 22, .
... is characterized in that the developer pressing surfaces 21C of the spiral blades 21b, 22b, ... are inclined upright with respect to the rotating shafts 21a, 22a, ... (see Fig. 5). ).

In such technical means, the developer pressing surface 21
The angle at which c stands upright with respect to the rotating shafts 21a, 22a, . . . is the direction in which the developer is perpendicular to the rotating shafts 21a, 22a, . (hereinafter referred to as the lateral direction), you can change the design of the angle as appropriate, but setting this angle extremely small will lead to a decrease in the developer conveying force in the axial direction. Therefore, it must be avoided, preferably from 5° to 30°.

In addition, as a method for raising the developer pressing surfaces of the spiral blades 21b, 22b, . . . at an angle with respect to the rotating shafts 21a, 22a, . When manufactured by the spiral blades 21b, 2
This can be achieved by making the cross-sectional shapes of 2b, . . . thicker on the shaft side and thinner on the tip side. In addition, a metal spiral blade 21b
, 22b, . . . are wound around the rotating shafts 21a, 22a, . . . to form the augers 21, 22, .
By twisting b, . . . , it is possible to easily tilt the developer suppressing surface 2tc. However, if the lead is set large with a gold III auger, the ability to convey the developer in the axial direction will deteriorate accordingly, so in order to tilt the developer pressing member 21C while maintaining the ability to convey the developer in the axial direction, it is necessary to As in the developing device described in 6, a plurality of spiral blades 21b, 22b, .
It is preferable that the augers 21, 22, .

Furthermore, the developing device according to a seventh aspect of the present invention addresses the fourth problem, that is, the one-degree unevenness caused by unstable adsorption of the developer to the developing roll. In the magnetic brush development method, the layer thickness of the developer adsorbed on the development roll is regulated by a trimming plate (hereinafter referred to as "trimmer") before the development area. It was inferred that the developer peeled off from the developing roll by the trimmer stagnates around the carrier due to poor fluidity, making the adsorption of the developer to the developing roll unstable. We devised a developing device.Specifically, upper and lower paddle wheels 1 and 7 degrees are arranged adjacent to the developing roll 1, and the rotation of the lower paddle wheel 7 causes the developing device to be placed in the developing orifice roll 1. While the developer is continuously supplied, the developer scraped off from the developing roll 1 by the trimmer 3 by the upper paddle wheel 7' is also collected and returned to the stirring means 2. According to this developing device, Since the developer is forcibly circulated in the adsorption area, the adsorption of the developer to the developing roll 1 is more stable than in conventional devices.

However, in this developing device, the circulation of the developer was improved more than expected, and this time, problems such as white streaks and other unevenness occurred in correspondence with the blades of the lower paddle wheel 7. In addition, since the number of rotating members increases, the assembly becomes troublesome, such as supporting the rotating shaft and installing gears for power transmission. It cannot be said that it is a means.

Therefore, as a result of further research taking these conditions into consideration, the applicants of the present application have come up with the development stomach described in claim 7.

That is, as shown in FIG. 7, the developing device according to claim 7 has a plurality of magnetic poles, attracts the developer according to the magnetic field formed between the magnetic poles, and also attracts the developer along a predetermined path including the developing area. A developing roll 1 transports the developer 1 along the axis and then peels it off, and mixes and stirs the developer peeled off from the developing roll 1 and replenishment toner, and supplies the agitated developer to the developing port 1. a stirring means 2; a trimmer 3 which is arranged to maintain a predetermined gap from the developing roll 1 and to equalize the layer thickness of the developer being conveyed; and a back plate 4 which is arranged parallel to the axial direction of the developing roller 1 and forms an auxiliary adsorption area in which the developing agent peeled off from the developing roll 1 by the trimmer 3 is filled and flows. It is characterized by Δ゛.

In such a technical means, the back plate 4 has a structure in which the developer peeled off from the developing roll 1 by the trimmer 3 is filled into an auxiliary adsorption area surrounded by the developing nozzle 1, the trimmer 3, and the back plate 4. As long as it is circulated and adsorbed to the developing roll 1 again, the specific arrangement position and the like may be changed as appropriate. However, when the back plate 4 is arranged as described above, if the positional relationship with the trimmer 3 is out of alignment, the flow of the developer in the suction area may deteriorate, and there is a possibility that the adsorption of the developer may be hindered. be.

Therefore, from the viewpoint of keeping the positional relationship with the trimmer 3 constant at all times and preventing an adverse effect on the recorded image, the trimmer 3 and the back plate 4 are arranged as in the developing device according to claim 8.
It is preferable to configure them integrally (see FIG. 8).

The evaluation of the developing system of the present invention is effective when using various developers with poor fluidity, but it is particularly effective when using "X microtoning type developer," specifically, when the saturation magnetization is 50 to 65.
About emu/a, carrier particle size is 20 μTrL ~ 6
It exhibits a remarkable effect when using a two-component developer of about 0μ door.

[Function 1] First, according to the developing device according to claim 1, a guide surface is provided along the developer conveyance path, and at the end of the guide surface, the developer peeled off from the developing roll is inside the stirring means. Since the guide for flowing is continuously provided, the developer released from the magnetic force of the developing roll does not form a swirling flow in the developing area. Therefore, the developer in the peeling region smoothly flows toward the stirring means along the guide surface and the guide surface, and the developer is prevented from jumping over the repulsive magnetic field and re-adsorbing to the developing roll.

Further, in the developing device according to claim 2 or 3, of the openings provided at both ends of the partition plate, the opening corresponding to the downstream side of the first auger is opened wider than the opening corresponding to the upstream side. Therefore, the discharge of the developer from the downstream side of the first auger is promoted, and the imbalance in the amount of developer deposited behind the developing roll is eliminated.

Furthermore, in the developing device according to claim 4, since the plate-like member erected on the rotating shaft of the auger presses the developer toward the opening of the partition plate as the rotating shaft rotates, each auger Transport of the developer between the stirring means is promoted, and unevenness in the amount of developer deposited within the stirring means is prevented.

Furthermore, in the developing device according to claim 5 or 6, since the developer pressing surface of the spiral blade of the auger is inclined upright with respect to the rotation axis, the developer is pushed in the wheel direction as the auger rotates. In addition to pressure, it receives lateral pressing force. Therefore, since the developer is laterally discharged by the spiral blade, agitation of the developer is promoted and transport of the developer between the respective augers is also promoted.

Next, the operation of the developing device according to claim 7 or 8 will be explained. As shown in FIG. 6, the developer scraped off by the trimmer 3 (hereinafter referred to as surplus developer) is removed by standing the back plate 4 at a predetermined distance from the developer nozzle 1 and the trimmer 3. The developer flows in the direction of the arrow in the area surrounded by the trimmer 3, the developing roll 1, and the back plate 4 (auxiliary adsorption area).The excess developer flows along the back plate 4 and flows into the auxiliary adsorption area. At the same time, the developer is pressed toward the developing roll 1 and adsorbed onto the developing roll 1 again.Therefore, the adsorption of the developer onto the developing roll 1 is made uniform and stable.

[Example 1] Hereinafter, a developing device of the present invention will be described in detail based on the accompanying drawings.

This example shows an example in which the developing device of the present invention is applied to the second developing means of an electrophotographic copying machine capable of forming a multicolor recorded image by the overlapping development method.

Prior to the explanation, first, a table of contents regarding this embodiment will be shown.

{Table of Contents} ■. Overview of electrophotographic copying machine■. Circuit configuration of electrophotographic copying machine■. Specific configuration of electrophotographic copying machine■. Configuration of second developing means■. Circulation of developer in the second developing means 1) Development area → Peeling area 2) Peeling area → Stirring means → Adsorption area 3) Adsorption area → Development area ■. Summary ■． 9 shows an external perspective view of a digital color copying machine having a developing device of the present invention, and FIG. 10 shows a schematic sectional view thereof.

The color copying machine has a platen 12 provided on the top side of the copying machine main body 10 on which a document (not shown) is placed, and an image information device provided below the platen 12 for inputting image information from the document. The reading section 14 and the both image information reading section 1
4, a transfer unit 30 that transfers the image formed on the image forming device 20 onto paper 16, which is a transfer medium, and supplies and conveys the paper 16. It includes a paper supply section 40 and a paper transport section 50.

The paper supply unit includes three paper trays 41 to 43 each containing paper 16 according to the size, and a large capacity tray 4.
4. The paper transport section 50 is composed of a double-sided tray 45 and a manual tray 46, and the paper transport section 50 includes a paper reversing chute 51 and a first paper transport path that transports the paper sent out from each of the trays 41 to 46 to the image forming apparatus 20. 52 and a second paper transport path 53 for transporting the copied paper to the image forming apparatus 20 again.

Further, the paper onto which the toner image has been transferred in the image forming device 20 is sent to the fixing device 60 through the discharge side conveyance path 54, and the toner image is fixed by the pressure roll 61 and heating roll 62 of the fixing device 60. After that, the paper is transported to a discharge tray 41.

■． Circuit Structure of Apparatus FIG. 11 is a block diagram showing an outline of the circuit structure of the color copying machine of this embodiment.

As shown in FIG. 11, a distributed CPU architecture using serial communication centered around the main CPU 221 is adopted. This is to enable optimal placement of the controller and provide optimal cost performance. Furthermore, from the perspective of product development of image forming apparatuses, modular design can be expected to shorten and improve the efficiency of software development, reduce costs, and facilitate troubleshooting.

In addition, processing efficiency increases due to the decentralization of processing by multiple CPUs, so for example, expensive 16-bit CPLJ
By using an inexpensive 8-bit CPU instead of using a 8-bit CPU, it becomes possible to process programs that are complex and require high-speed processing.

Furthermore, such decentralization of processing facilitates model expansion. That is, even when developing a new input/output device, it may not be necessary to modify the program on the main body side (main CPU side), and even if changes are necessary, they can be kept to a minimum.

Furthermore, regarding the printed circuit board on the main body side, there is no need to store unnecessary I/O ports or programs due to CPU distribution. Therefore, it is possible to reduce the cost of the printed circuit board, and the degree of freedom in the arrangement space is improved.

This color copying machine has a main C in the main body 10 of the copying machine.
P U 221 and CPU 22 for intermediate image lamp
2 controls the Thursday holiday 10. This interimage lamp CPU 222 is a CPU that specializes in controlling the interimage lamp, and the interimage lamp is a CPU that irradiates light onto the latent image carrier 70 (hereinafter referred to as a photosensitive drum) after exposure. This lamp is used to erase a portion of an electrostatic latent image before development. Also,
Since the copying machine of this embodiment is equipped with a function for editing images, etc., the interimage lamp is also used to limit the formation of an electrostatic latent image to a predetermined area.

For this purpose, an independent CPU is used in addition to the main CPU 221.

In the copying machine of this embodiment, the following CPIJ is used, and each CPtJ has communication lines 223 and 22.
Connected by 4.

(1) Document feeding CPU 225: This is a CPU that controls the automatic paper feeder and the like.

■ Sorter CPU 226: This is a CPIJ placed in the sorter (not shown).

(1) Display CPU 227: This is a CPU used to display various information in kanji on the liquid crystal display section 1ta attached to the console panel 11 and to display an area for editing.

(1) Tray control CPU 228: This is a CPU for controlling trays added to the copying machine main body 10. This CPU is arranged at the rear side of the tray cabinet that accommodates each tray, and performs these controls according to the trays arranged. Among these trays, the intermediate tray 45 (double-sided tray) is equipped with its own motor for conveying copy paper, and the copy paper stored in this tray is controlled in a complex manner such that the storage position differs depending on its size. It has become so.

■Card CPL 1229: This is a part that reads and corrupts an IC card when it is used to specify the coordinates of a document.

FIG. 12 shows the circuit configuration centered around the main C P Ll 221 in more detail.

As described above, the main CPυ 121 is connected to the DADF 13 (automatic double-sided document feeder), the sorter 15, the liquid crystal display section 11a1, the editor button 232, the inter-image lamp controller 239, and the tray control section 233 through the serial communication lines 223 and 224, as described above. ing.

Further, the main CPU 221 has a built-in A/D converter, and is connected to the following parts through an analog data line 234. An example of such a CPU is μPD 7810CW1μP manufactured by NEC Corporation.
D 7841C W and M 8 8 manufactured by Fujitsu Ltd.
An 8-bit one-bup CPU such as 9713X can be used.

(2) Light quantity sensor 235: This is a sensor used when detecting the light beam of an exposure lamp (not shown) and performing its if, {J Ii1l.

(2) Lagoon temperature sensor group 236: This is a sensor such as a soft touch sensor for controlling the fixing temperature.

(2) Paper size sensor group 237: This is a sensor that detects the size of paper stored in the paper supply section 50 or the like. According to the system configuration of the copying machine of this embodiment, copy paper can be delivered from a maximum of four types of trays.

Furthermore, the main CPU 221 has a reset circuit 238.
In addition to being reset at the time of runaway or initialization, it is also connected to the following parts via the bus line 221A.

■Keyboard Display LSr (Large Scale Integrated Circuit)
221B: This is a circuit that mediates data with the console panel 11.

■Timer/counter LSI 221C: This is a circuit that controls the drive of the main motor 240.

■ROM 2210: This is a read-only memory that has a capacity of 56K bytes and stores various control programs.

■RAM 221E: This is a random access memory for data storage with a capacity of 6K bytes. This RAM221F has non-volatile memory (NVM).
) 221F is connected and the copier is turned off.
This allows you to save the necessary data even if this happens.

(1) First I/O controller 221G: This is an input/output controller that inputs various data via the filter circuit 221H and drives various parts via the driver circuit 221I.

(2) Second I/O controller 221J: This is an input/output controller that inputs various data via the filter circuit 221K and drives various parts via the driver circuit 121.

■． Specific Structure of the Apparatus FIG. 13 shows an enlarged cross-sectional view of the main parts of the image forming apparatus installed in the color copying machine of this embodiment.

The image forming apparatus includes a photosensitive drum 70, a charger 12 arranged sequentially along the outer periphery of the photosensitive drum 70, a first latent image forming means 74, and a first developing stage 80 (hereinafter referred to as A latent image forming device 76, a second developing device 100 (hereinafter referred to as a second developing device), and a pre-transfer charger 78, and a latent image formed on the photosensitive drum 70. The visualized image is transferred onto the paper 16 in a transfer section 30.

In the image forming HN configured as described above, in order to record a color image, as shown in FIGS. 72, the photosensitive drum 70
The upper surface is uniformly charged, and the surface potential of the photosensitive drum 70 becomes charged to one polarity (negative) (see Fig. 14).
a)). In this state, the first latent image forming means 7
After the first latent image is formed on the photosensitive drum 70 in step 4 (
By applying a predetermined developing bias voltage to the first developing device 80 (see FIG. 14(b)), a first toner image is formed by reversal development (see FIG. 14(c)). Next, a second latent image is formed on the photosensitive drum 70 by the second latent image forming means 16 (see FIG. 14(d)), and a predetermined developing bias voltage is applied to the second developing device 100. As a result, a toner image is formed on the photosensitive drum 70 by regular development (see FIG. 14(e)), and the pre-transfer charger 1
After the polarities of both toner images are aligned by 8゛ (see FIG. 14(f)), both toner images are transferred onto the paper at once in the transfer section 30, so that a color image is recorded. It has become.

In this case, the first and second latent image forming means 74, 76
is formed by a laser diode, and writes a predetermined latent image on the photosensitive drum 70 in response to a signal from the image information reading section 14. In this case, the first latent image forming means 74 is of a type that writes the image area, and the second latent image forming means 76 is of a type that writes the background area. There is no need to use a method in which the first latent image forming means 74 writes the background part and the second latent image forming means 76 writes the image part, or both the latent image forming means 74 and γ6 write the image part. Alternatively, a method may be used in which the background portion is written.

The first developing device 80 has a two-component developer for color (red), and includes a developing roll 81 disposed on the photosensitive drum 70 side and a partition 82 on the back side of the developing roll 81. A first auger 83a and a second auger 83b are provided together, and a third auger 83 is provided above these augers 83a and 83b via a receiving plate 84.
C, and a film-shaped sealing member 85 that is attached to the upstream side of the opening of the housing 80a and contacts the photosensitive drum 70.
a blade 86 for scraping off the toner conveyed by the developer nozzle 81; and a toner conveying coil auger 87a and a toner conveying auger 87b installed in the toner box 87. It is composed of.

In this case, the developing roll 81 is made of a non-magnetic conductive member such as aluminum alloy or stainless steel.

The second developing device 10G is a developing device having a black two-component developer, and develops the second latent image using an FX microtoning magnetic brush developing method.

Note that the details of the second developing device will be explained in the next section (2) onwards.

Further, the first and second developing units 80 and 100 are provided at the back and can be moved toward and away from the photosensitive drum 70 alternately by a tract machine MI1200.

The retract mechanism 200 moves the first and second developing units 80 and 100 toward and away from the photosensitive drum 70. Since both developing units 80 and 100 have the same structure, here, only the first developing unit is used. The retract mechanism 200 of 80 will be explained with reference to FIG.

The retract mechanism 200 includes a crank portion 202 formed on a crankshaft 201 that is rotated by a drive source (not shown).
and a yoke cam 203 that follows this crank part 202.
Then, an elastic force is applied in a direction to keep these crank portion 202 and yoke cam 203 in constant contact, and a return spring 204 is applied to separate the developing device 80, and an elastic force is applied in a direction to always bring the developing device 80 closer to the photosensitive drum 70 side. 205.

In this case, the yoke cam 203 has a guide slot 209 that guides the guide bin 208 that is slidably fitted into the forked arm 201 provided on the holder 206 of the developing device 80.
is formed (see FIGS. 16 and 17).

The crank portion 202 of the crankshaft 201 formed as described above and the yoke cam 203 are engaged as shown in FIGS. 16 and 17, and when the developing device 80 is separated,
When the crankshaft 201 rotates counterclockwise from the autumn state (not shown in FIG. 16), the yoke cam 203 is moved in the separating direction (to the right in FIG. 16) against the elastic force of the pressure contact spring 205, and the developing device 80 is reliably separated from the photosensitive drum 70. Further, in order to bring the developing device 80 close to the photosensitive drum 10, the crankshaft 201 is rotated counterclockwise from the state shown by the imaginary line in FIG.
Since the yoke cam 203 is moved in the approaching direction (to the left in FIG. 16) against the elastic force of the developing device 80, the developing device 80 is brought close to the photosensitive drum 70 and set in a developing state. In this case, the pressure spring 205 is connected to the developing device 8.
A pair of guide shafts 211 protrude from the holding part 206 that holds the housing 80a of 0 toward the back side (right side in FIG. 15) of the housing 80a, and are slidably fitted into the U-shaped movable body 210. 211 and are formed of coil-shaped compression springs that are compressed between the holding portion 206 and the movable body 210. The return spring 204 is a coiled tension spring whose one end is attached to the fixed side of the copying machine main body 20 and the other end is attached to the movable rest 210. The guide pins 208, which are fitted into the bifurcated arm 207 of the holder 206 and the guide hole 209 of the yoke cam 203, are provided on both sides of the U-shaped movable body 210, respectively.

In FIG. 15, reference numeral 123 indicates the first and second developing units 80. Tracking rolls 90 are provided on both sides, and 213 is a guide bin slidably supported in a guide groove 214 of a guide frame 215 provided in the main body 10 of the copying machine.

The pre-transfer charger 78 has a structure in which a grid electrode 78b is disposed in the opening of a shell 7F3c having a U-shaped cross section, in which a wire electrode 78a is stretched.
A high voltage is applied, and a DC control voltage is applied to the grid electrode 78b.

The transfer unit 30 includes a transfer corotron 33 in which a wire electrode 32 is stretched in a shell 31 having a U-shaped cross section that opens toward the photosensitive drum 70 side, and a transfer corotron 33 disposed downstream of the transfer corotron 33 and connected to the photosensitive drum. Two wire electrodes 35. 35
and a peelable corotron 36 which are stretched parallel to each other.

Note that a photosensitive drum 70 is installed downstream of the transfer unit 30 after the transfer.
A peeling claw 18 is provided for peeling off the paper 16 to be served from the photosensitive drum 10, and a cleaning device 19 is provided downstream of the peeling claw 18 for removing residual toner adhering to the photosensitive drum 70. It is arranged. in this case,
The cleaning device 19 includes a cleaning blade 19a that scrapes toner adhering to the photosensitive drum 10, a rotating brush roll 19b provided upstream of the cleaning blade 19a, and a toner receiver provided upstream of the rotating brush roll 19b. 19c and this toner tray 1
The photosensitive drum 70 is attached to the photosensitive drum 70 side of 9c.
and a film seal 19d for preventing toner scattering that comes into contact with the toner scattering prevention film seal 19d.

IV. Configuration of second developing means Here, a second developing device 100 to which the developing device of the present invention is applied
I will explain the basic configuration of. It should be noted that other inventions that occurred during the process of devising the present invention can also be applied to the second embodiment 4 & device 100, but in this section, only the configuration of the first embodiment will be explained, and other inventions based on other inventions will be described. Other embodiments in which various parts are changed will be described later in the next section.

FIGS. 1 and 2 show a second developing device 10 according to the first embodiment.
It indicates 0. The second developing device 100 develops the second latent image formed on the photosensitive drum 70 by an FX microtoning magnetic brush developing method, and is generally disposed at one end of the housing 101 and has an opening. A developing roll 102 (developer carrier) with a part of its outer peripheral surface exposed outside the housing 101 and the developing roll 10
a developer stirring means 103 disposed inside the housing 101 on the rear side of the developer roll 102; and a developer magnetic brush ear attached to the top plate of the housing 101 above the developer roll 102 and formed on the developer roll 102. It is composed of a trimmer plate 104 (trimmer) that regulates the height of the crop.

In addition, various auxiliary equipment required for carrying out the FX microtoning method are installed (:J).

First, the developing port 102 has a rotatable cylindrical sleeve 122 disposed around the outer periphery of a fixedly supported substantially cylindrical magnet member 121. The magnetic force of the magnet member 121 causes the sleeve 122 to be The conventional magnetic brush development method is similar to the conventional magnetic brush development method in that a magnetic brush of the developer is formed in the area and the magnetic brush is conveyed to the development area facing the photosensitive drum 70 as the sleeve 122 rotates.
That is, it is similar to the developing roll of the first developing device 80. The magnet member 121 includes a peeling pole Nl, a conveyance Ifl
A plurality of magnetic poles such as s3, N3, development poles 31 and 32 are provided in order in a counterclockwise direction, and these are magnetized by a magnetization method on a ferrite Macnet roll. In the developing roll 102 of the present embodiment having such a magnetic pole arrangement, magnetic poles of different magnetic properties are alternately successive: attraction pole N2→transport pole S3→transport pole N3→developing main challenge Sl,
The developer is held on the surface of the sleeve 122 between S2 and the suction pole N1, while the developer is peeled off from the sleeve 122 between the separation pole N1 and the suction pole N2 where VitlI4i of the same magnetic property are arranged adjacent to each other. In addition, a repulsive magnetic field is formed between S1 and S2 of the main developer scoop, and the magnetic forces of 31 and S2 are spread at a predetermined angle and act on the developer. This is a configuration unique to the FX microtoning method, in which the magnetic force temporarily weakens and the developer can be rubbed against the photosensitive drum 70 with high efficiency. In this embodiment, the magnetic force of each magnetic pole and the outer diameter of the sleeve 122 are as follows.

Peeling pole Nl: 950 Gauss Adsorption pole N2: 500 Gauss Transport pole S3: 600 Gauss N3: 800 Gauss Developing main pole 31: 1250 Gauss S2: 1250 Gauss Sleeve outer diameter: 24.5 m Note that it is attracted to the same magnetic stripping pole N1. When the pole N2 is provided by the magnetization method, different magnetic poles Iif & pole S are likely to occur between the two magnetic poles, and when this magnetic pole S occurs, there is an attraction between the stripped pole N1 and the attracting pole N2. A magnetic field is created, making it impossible to completely peel off the developer from the developer roll 102.

Therefore, when magnetizing the magnetic poles, care must be taken not to generate different magnetic poles between the two magnetic poles. According to experiments conducted by the inventors of the present application, it has been confirmed that the developer can be completely peeled off from the developing roll 102 if the magnetic force between the two magnetic poles falls to the same magnetic side to about 0 Gauss to 50 Gauss. ing.

Further, tracking rolls 123 are rotatably arranged in parallel on the outer sides of both ends of the developing roll 102 configured as described above, and when the tracking aperture roll 123 comes into contact with the photosensitive drum 70, the developing roll 102 and the photosensitive drum 70 are brought into contact with each other. The gap between the drums 70 is maintained. In addition, developing roll 1
A seal member (not shown) is provided between both ends of the tracking roll 123 and the tracking roll 123 to prevent the tracking roll 123 from becoming contaminated with floating toner and disrupting the accuracy of contact with the photosensitive drum 70. ing.

On the other hand, the stirring means 103 includes a first auger 105 and a second auger 10B, which are disposed so as to be axially aligned with the developing roll 102, and is provided upright in the housing 101 so as to separate these two augers. It is composed of a partition plate 111. The first auger 105 and the second auger 106
The rotating directions of the two augers 105 and 105 are determined so that the developer transport directions are opposite to each other.
> and the area where the second auger 106 is arranged (hereinafter referred to as the second stirring path 108) are provided with an opening that communicates with the area where the second auger 106 is disposed.
The first stirring path 107 and the developer circulate. Further, a toner replenishment passage 109 that communicates with a toner box (not shown) is protruded from the downstream end of the first agitation passage 107, and the toner replenished from this replenishment passage 109 is transported by the first auger 105. The developer flows into the second storage stirring path 108 together with the developer, and is uniformly mixed with the developer before being circulated to the first stirring path 107.

In this embodiment, the openings provided at both ends of the partition plate 111 are from the first stirring path 101 to the second stirring path 1.
◇An opening 112 (hereinafter referred to as an outflow opening) through which the developer flows out to 8 has an opening width of 30 m, and an opening 113 (hereinafter referred to as an inflow opening) through which the developer flows from the second stirring path 108 to the first stirring path 107. ) is formed to have an opening width of 25s, and the opening width of the outflow opening 112 is designed to be larger than that of the inflow opening 113. Further, both of the openings are connected to the developing roll 102.
It is provided outside the developable area in the axial direction so as not to overlap the developable area (an area with width in the axial direction in which the electrostatic latent image on the photosensitive drum can be developed).

In addition, in this embodiment, each auger 105j06 is manufactured by copper molding of synthetic resin, and as shown in FIG. The base side is thicker than the tip side, and a plate-like member 110 is provided at the downstream side of each auger 105106 so as to face the inflow opening 113 or the outflow opening 112.
It is erected at 06a.

As mentioned in Suimei MA, the developer used in the FX Mike [] toning method has very poor fluidity compared to conventional developer. Therefore, in the developing device 100 of this embodiment, a paddle wheel 114 having a plurality of blades 114a parallel to the axial direction is provided between the developing roll 102 and the stirring means 103, and the rotation of the paddle wheel 114 is controlled by f1'. , the developer peeled off from the developing roll 102 is forcibly conveyed to the stirring means 103, while the stirring means 10
The developer mixed and stirred by 3 is continuously transferred to the developing roll 1.
02 is adopted.

Further, in the developing device 100 of this embodiment, the developing port 1
A back plate 115 is provided vertically from the top plate of the housing 101 on the back side of the housing 101 above the paddle wheel 114.

This is a measure to make the adsorption of the developer to the developing roll 102 uniform, and by vertically disposing this back plate 115, the adsorption area (the developer conveyed to the paddle wheel 114 is adsorbed to the developing roll 102). An auxiliary adsorption area is formed above the developing roll 102, and the developer scraped off from the developing roll 102 by the trimmer 104 is filled in this auxiliary adsorption area and flows clockwise. still,
This back plate 115 is formed integrally with the trimmer 104 and is fixed to the housing 101 with screws.

Furthermore, the FX microtoning method has a drawback in that in the developing area, the toyria that has been transferred breaks the restraint of magnetic force and is easily transferred to the photosensitive drum 70 side. A catch-up roll 116 is provided to catch the image and pull it back toward the developing device. The feed rolls 116 are arranged below the developing roll 102, that is, on the downstream side in the rotational direction of the photosensitive drum 70. The structure is similar to that of the developing roll 102, in which a rotatable cylindrical sleeve 118 is provided around a magnet member 111 having magnetic poles N' and S'. The carrier transferred to the top is adsorbed onto the sleeve 118.

This catch-up roll 116 extracts power from the rotating shaft 123 of the developer roll 102 and rotates in the opposite direction to the developer roll 102, but since it rotates at an extremely low rotation speed than the developer roll 102, the power transmission is limited. It is necessary to provide a deceleration mechanism in the process. However, when considering the space saving of the developing unit, it is not possible to set a large reduction ratio by using gears. are doing. Specifically, as shown in FIG. 21, an eccentric cam 120a is fixed to the rotating shaft 102a of the developing roll, and a rod 120 loosely fitted to the cam 120a is fixed.
One end of the catch-up roll 116 is fixed to the rotating shaft 116a of the catch-up roll, and as the cam 120a rotates, the end 120b swings to drive the catch-up roll 116 intermittently at low speed.

Further, when disposing the catch-up roll 116, it is necessary to dispose the catch-up roll 116 so that its magnetic force does not extend to the developer transport path from the development area around the development roll 102 to the peeling area.

If there is a catch-up roll 1 in the developer transport path mentioned above,
When the magnetic force of sleeve 16 is lν, the developer is
This is because the developer that has peeled off from the developing device 2 and stagnates around the developing port 102 and has passed through the developing area overflows to the outside of the developing device. Therefore, in the developing device 100 of this embodiment, the magnetic force of S° is smaller than the magnetic force of 82, 600 Gauss,
The magnetic force of N° was set to 600 Gauss, which is smaller than the magnetic force of N1, and both magnetic poles were arranged so that S′ faced the photosensitive drum. In addition, the magnetic force of the developing nozzle roll 102 and the magnetic force of the catch-up roll 116 are sharply set so that the boundary where they balance and cancel each other out (hereinafter referred to as "magnetic force saturation boundary") is located outside the developer transport path. An up roll 116 is provided (see Fig. 22).In this embodiment, the sleeve diameter of the catch up hole 116 is 12ffil,
The outer peripheral surface of the developing roll 102 and the catch-up opening roll 11
The gap with the outer peripheral surface of No. 6 is 4 mm.

Furthermore, the housing 101 in which the above-mentioned elements are arranged is made of synthetic resin, and its bottom plate shape is arranged inside so that the developer with poor fluidity will not be transported and stagnate. It is molded to match the outer circumferential shape of the shaft. In particular, from the developer roll 102 to the paddle wheel 11
4, the bottom plate has a guide surface 124 that guides the developer adsorbed on the developing roll 102 to the peeling area, and a guide surface 125 that guides the peeled developer to the paddle boiler 114, and this guide surface 124 and the guide surface 125 is determined from the relationship between the magnetic forces of the peeling pole N1 and the attraction pole N2, the flow of the developer after being peeled off from the developing roll 102 is promoted. Developing roll 102 via member 128
A side block 12γ protrudes that abuts both ends of the housing 101, thereby allowing the developer in the housing 101 to flow into the developing device 1.
00 is prevented from leaking outside.

By the way, in a developing method using a two-component developer, by mixing and stirring toner and carrier in a developing device,
When the toner is charged to a predetermined amount, the electrostatic latent image on the "C" photosensitive drum can be developed. However, when the housing 101 is made of synthetic resin as described above, the housing 101
As the charge matrix increases, a so-called charge-up phenomenon occurs in which the toner is charged above a predetermined value, or toner charged to the opposite polarity is generated, making it impossible to fully utilize its developing ability. Therefore, in this embodiment, a thin plate (SUS) with excellent conductivity is installed inside the bottom plate of the housing 101.
, aluminum, etc.), and this rough plate is grounded outside the developing device, thereby reducing the charging capacity of the housing 101.

In this embodiment, as a method for supporting the rotating shafts of the augers 105, 106 and the paddle wheel 114 on the housing 101, as shown in FIG. In addition, a bearing portion 129 into which this stud 128 fits is provided at one end of the rotating shaft, and the stud 128 and bearing portion 129 are fitted to support one end of the rotating shaft.
The other end is supported by the housing 101 by interposing a bearing 130 between the rotating shaft and the housing 101 and fitting a fixing ring onto the rotating shaft. Therefore, the positioning of the rotating shaft only needs to be performed at the end of the shaft where the bearing 130 is fitted, making the fixing work easier compared to the conventional method of fitting bearings at both ends. Also, since the shaft end of the rotating shaft is not exposed outside the housing 101 on the stud side, the housing 10
There is no need to provide a cover on one side, and in this respect as well, the developing device has a simpler configuration than conventional developing devices. Incidentally, the reference numeral 131 indicates each auger 105, 106.
and a gear for transmitting power to the paddle wheel 114, so that it rotates at a rotation speed corresponding to each function.
The gear ratio is set.

V. In this section, the characteristics of the circulation of the developer inside the second developing device 100 whose structure was explained in the previous section will be explained, and other embodiments that can achieve the same circulation of the developer will also be explained. explain.

1) Development area→Peeling area (hereinafter referred to as developer recovery path) The developer that has rubbed on the photosensitive drum 10 in the development area is transferred to the main development pole S2.
It is held by the sleeve 122 of the developing roll 102 by the magnetic field formed between the peeling pole N1 and the peeling pole N1, and is collected inside the developing device. At this time, in the developing device of the first embodiment, as described in the previous section, the placement position of the key 1/touch-up hole 116 is determined by the relationship with the magnetic force of the developing hole 102. The magnetic force of the catch-up roll 116 is not applied to the developer recovery path, and the developer is smoothly recovered inside the developing device.

And the developer collected inside the developing device is peeled off! fAN
However, in the developing device of the first embodiment, the guide surface 1 provided on the bottom plate of the housing 101
24 and the guide surface 125, the structure is such that the developer can be reliably peeled off from the developing nozzle 102.

At this time, the formation position of the guiding surface 125 is the point where the magnetic force suddenly drops between the peeling pole N1 and the attracting pole N2 due to the repelling magnetic field, that is, the point where the developer is actually peeled off from the developing port 102. P (hereinafter referred to as the peeling point), if the formation position of the guiding surface 125 is extremely close to the peeling pole N1, the peeled developer will not be regulated by the guiding surface 125 and will flow in a swirling manner. This causes the developer to stagnate around the developing roll 102 (Fig. 24(a)).
reference). In addition, if the formation position of the guiding surface 125 is extremely close to the peeling point, the peeled developer may be exposed to the developer hole 102.
Since a swirling flow occurs between the guide surface 124 and the guide surface 124, the developer becomes clogged in the recovery path (see FIG. 24(b)).

For these, the guiding surface 125, ? When formed at an appropriate position between the l+ separation point and the peeling pole N1, the guiding surface 125 prevents the swirling flow of the developer peeled off from the developing roll 102, so that the developer flows along the guiding surface 125. It is possible to avoid troubles such as the developer flowing smoothly and being absorbed by the developing roll 102 again, which has been collected, or the developer overflowing outside the developing device due to clogging of the developer recovery path (Fig. 24). (See (C)).

Furthermore, regarding the guide 124, the developing roll 102
If the gap between the developing roll 10 and the guide surface 124 is large, the developing roll 10
The magnetic force of No. 2 cannot completely hold the developer flowing through this gap, and developer flow similar to that shown in FIG. 24(b) occurs, resulting in developer clogging. Further, even if the above-mentioned gap is small, developer clogging also occurs. Therefore, the gap between the guide surface 124 and the developing roll 102 is
It needs to be determined based on the magnetic force of the developing port 102 acting on the developer recovery path and the fluidity of the developer.

In this embodiment, the angle between the separation pole 81 (950 Gauss) and the attraction pole N2 (500 Gauss) is 80'', and the angle between the separation point and separation pole N1 is 60'' from the ratio of the magnetic forces of both magnetic poles. It is thought that ゜.

Therefore, the angle between the guiding surface 125 and the peeling pole N1 was set to 30 degrees, and the gap between the developing roll 102 and the housing bottom plate was set to 2 to 31111 degrees. When samples of recorded images were collected using the developing device of the first embodiment manufactured according to these values, no white spots occurred in the recorded images, and the collected developer was reliably peeled off from the developing roll 102. It was confirmed that It was also confirmed that the developer did not overflow from the developing device and was smoothly collected into the developing device.

In the first embodiment, the shape of the bottom plate of the housing 101 is improved to actively flow the peeled developer and prevent it from being re-adsorbed onto the developing roll 102.
As shown in the figure, a rod-shaped member 135 parallel to the developing roll 102 may be disposed between the peeling area and the adsorption area. According to this, the peeled developer is removed from the developing roll 1.
Since the developer is prevented from flowing along the circumferential direction of 02, the developer does not jump over the repulsion magnetic field formed by the stripping pole N1 and the attracting pole N2 and move to the attracting area. Similar to the embodiment, re-adsorption of the developer can be prevented.

2) Peeling region→stirring means→adsorption region The developer peeled off from the developing roll 102 as described above is first conveyed to the stirring means 103 by the rotating paddle wheel 114.

This paddle wheel 103 also plays the role of supplying developer to the developing port 102, but since its purpose is to smoothly convey developer with poor fluidity, the following points are considered in terms of its function: It is necessary to determine its shape with consideration given to the following. First and foremost, the developer must have such a conveying ability that the developer peeled off from the developing roll 102 does not stagnate around the developing roll 102 . The second method is to supply the developer substantially uniformly to the developing roll 102, and to apply the blades of the paddle wheel to the surface of the developing roll 102.
The purpose is to prevent the white stripe pattern corresponding to 14a from occurring. Furthermore, as a third, mutually adjacent blades 1
The purpose is to ensure that the developer flowing into the spaces 14a (hereinafter referred to as pockets) is replaced.

In view of the above three points, the inventors of the present application have developed the paddle wheel 114.
I searched for a shape, and at that time, I directed my thinking as follows. That is, regarding the first point to note, the amount of developer that can be conveyed per unit time by the paddle wheel 114 (pocket volume and wheel (determined by the number of rotations), while for the second point to note, the thickness of the blade 114a is made thinner and the number of rotations is increased.

Furthermore, the third point to keep in mind is to make the opening width larger than the depth of the pocket. Based on this policy, various paddle wheels were prototyped and experiments were carried out to collect sample recorded images. As a result, the number of rotations of the paddle wheel 114 was set to be 1.5 times or more than that of the developing aperture wheel 102.
When the opening width of the pocket (Fig. 26, reference numeral B in the figure) is 2-8 of its depth (reference mark A in the figure), and the thickness of the blade 114a is 2M or less, a good recorded image with no density unevenness is obtained. It was confirmed that the developer was collected from the developing port 102 and the developer was supplied to the developing roll 102 smoothly.

Therefore, in the first embodiment, the rotation speed of the paddle wheel 114 is 250 rpm, the number of blades is 6, the outer diameter is φ16, and the depth of the pocket is 3. 5! IrIR, vane 114a
The wall thickness was 1#.

In FIG. 26, the blades 114a of the paddle wheel are erected in a radial pattern, but from the viewpoint of making it easier to dispense the developer from the pocket, it is necessary to slightly change the blades as shown in the embodiment shown in FIG. The blades 114a may be provided upright with a relief angle (30° in the figure), and even in this case, smooth circulation of the developer can be obtained as in the first embodiment.

The developer transported to the stirring means 103 in this way is
First, the first O is conveyed in the ring direction by 105 and flows into the outflow opening 1 together with the replenishment toner that has flowed into the inside of the developing device.
12 to the second stirring path 108 . Next, the toner is conveyed in the axial direction within the second stirring path 108 by the second auger 106, during which time it is uniformly mixed with the replenishment toner and the toner content is increased to a predetermined value. Furthermore, a second stirring path 10
8 through the inflow opening 113 to the first stirring path 10
7 and is fed to the paddle wheel 114 by the first auger 105.

At this time, according to the developing device of the first embodiment, the outflow opening 1
12 has a wider opening width than the inflow opening 113, and the maximum amount of developer that can flow into the first stirring path 107 per unit time can flow out from the first stirring path 107. The maximum amount of developer is large. Therefore, the developer flows out more easily in the first stirring path 107 compared to its inflow.
This eliminates the disadvantage that more developer is likely to accumulate on the downstream side than on the upstream side of 07, and the supply of developer to the paddle wheel 114, that is, the supply of developer to the developing nozzle 102, becomes uniform in the axial direction. It is something that will be done.

In addition, since the inflow opening 113 and the outflow opening 112 are opened outside the developable area of the developing roll 102 in the axial direction, as described in the previous section, the inflow or outflow of the developer Even if the amount of developer deposited is uneven on both ends of the first stirring path 107, it will not affect the development of the static N latent image.

By adjusting the radius and position of the openings 112 and 113 formed in the partition plate 111 of the stirring means 103 in this way, poor conveyance of the developer between the first stirring path 107 and the second stirring path 108 can be prevented. Although it is possible to sufficiently prevent m degrees of unevenness in the recorded image, in addition, in the developing device of the first embodiment, by improving each toning gas 105106, the difference between each stirring path 107 and 108 is improved. The developer is actively transported.

That is, as described in the previous section, the outflow opening 112
The plate-shaped member 110 is provided upright on the rotating shaft 105a of the first auger 105, which faces the inflow opening 113, and the rotating shaft 106a of the second auger 106, which faces the inflow opening 113. As a result, the developer that has reached the downstream end of each of the stirring paths 107 and 108 receives a lateral pressing force from the plate-like member 110 as the augers 105 and 106 rotate, so that it passes through each of the openings 112 and 113. The developed developer is transported smoothly, and density unevenness in recorded images is prevented.

Furthermore, in order to circulate the developer within the stirring means 103 as described above, in the developing device of the first embodiment, the augers 105, 1
By improving the shape of the spiral blades 105b and 106b of No. 06, it is possible to eliminate density unevenness caused by poor stirring of the developer.

As shown in the previous section, the cross-sectional shape of the spiral blades 105b and 106b is thicker on the rotating shaft side and thinner on the tip side, so that the spiral blades 105b and 106b press the developer when rotating.
One surface (developer pressing surface) of 106b is the rotating shaft 105a, 1
It stands upright at an angle to 06a. Therefore, as the A-gagers 105 and 106 rotate, a lateral pressing force is applied to the developer in addition to an axial pressing force, and the developer is moved horizontally by the spiral blades 105b and 106b. The mixture is dispensed, and its agitation is promoted.

In addition, when the developer pressing surface is erected at an angle with respect to the rotation axis in this way, as the angle between the developer pressing surface and the rotation axis becomes smaller, the ability to convey the developer in the axial direction does not decrease. Your abilities will improve. Therefore, in order to improve the stirring ability and maintain the conveying ability, it is necessary to take measures such as increasing the rotational speed of the augers 105 and 106.

In the first embodiment, the ratio between the conveyance capacity and the adjacent stirring capacity was approximately 4:1, and the rotational speed of the augers 105 and 106 was set to 232 rpm, which was slightly higher than that of the conventional product.

In addition, each auger 105106 of the first embodiment described in the previous section
was manufactured by injection molding of synthetic resin, but SUS
It is also possible to manufacture it from metals such as. FIG. 28 shows a second embodiment of a metal auger, with a rotating shaft 105a
It is manufactured by winding a spiral blade 105b (106b) around (106a), but by setting the lead of one turn of the spiral blade large and increasing its twist, the developer can be The pressing surface is erected at an angle with respect to the rotation axis. However, if the lead is set to a large value (4), the developer conveyance capacity in the axial direction inevitably decreases, so in the auger of this second embodiment, the two spiral blades 105b are arranged alternately with respect to the rotating shaft 105a. We are trying to maintain the wrapping and conveying ability. Furthermore, according to this metal auger, the lead is set large and the developer conveyance speed is increased, while the developer conveyance ability and agitation ability are compatible, so the rotation speed can be lowered. This leads to a reduction in noise, and the impact on the developer is reduced, making it possible to extend the life of the developer.

In addition, for synthetic resin augers, the plate-shaped member 1 is made by injection molding.
10 was installed upright on the rotating shaft 105a (106a),
When using such a metal auger, it is possible to fix a plate-like member prepared as a separate member to the rotating shaft by welding. However, considering the time and effort involved in fixing the fixing work, as shown in FIG.
a is provided at the end of the plate member 110, and this fixed leg 110a
It is preferable to wrap it around the rotating shaft 105a and install it upright (see FIG. 30).

The developer circulated in the stirring means 103 as described above is uniformly supplied in the axial direction of the paddle wheel 114, and is conveyed to the developing roll 102 by the paddle wheel 114.

3) Attraction area→Development area (hereinafter referred to as developer supply path) The developer conveyed to the development roll 102 is attracted to the surface of the sleeve 122 by the magnetic force of the attraction pole N2, forming a magnetic brush, and is also connected to the attraction pole N2. The developer is transported along the developer supply path as the sleeve 122 rotates while being held by the magnetic field formed between the transport pole S3 and the developer supply path.

A trimmer 104 is provided in the middle of the developer supply path between the transport pole S3 and the transport pole N3, so that the transported developer is trimmed by the height of the magnetic brush. 104 and the sleeve 122,
It is transported to the development area with a constant layer thickness.

On the other hand, the developer scraped off by the trimmer 104 descends from the housing 101 along the vertically disposed rear plate 115 and flows to the suction area. However, a part of the developer that has descended along the back plate 115 is affected by the rotation of the developing roll 102 and is moved along the developing roll 102 to the trimmer 10.
It flows in 4 directions! 1'.

As a result, the back plate 115, the trimmer 104 and the developing port
In the auxiliary adsorption area surrounded by the roller 102, a special developer flow is formed in which the developer scraped off by the trimmer 104 is filled with slight pressure and circulates in the opposite direction to the rotating direction of the developing roll 102. Zareru.

For this reason, the developer flowing in the auxiliary suction area is pressed (squeezed) against the developing roll 102 on the upstream side of the reamers 1 to 104, and is adsorbed to the developing nozzle roll 102 again. The developer is adsorbed substantially evenly over the entire outer circumferential surface of the sleeve 122, making it possible to prevent density unevenness in the recorded image due to insufficient adsorption of the developer.

At this time, as for the vertical length of the back plate 115, according to experiments by the inventors of the present invention, the lowest end of the back plate 115 is the adsorption electrode N2.
It is understood that if the developer is located between the poles and the transport pole S3 (within the angle θ in FIG. 31), the density unevenness of the recorded image will be reduced and the developer flow as described above will be formed. ing. When the lowermost end of the back plate 115 coincides with the center between the two poles (the position at angle θ/2 in FIG. 102 was confirmed to be adsorbed.

By the way, as described in the previous section, the side blocks 127 protruding from the housing 101 are in contact with both ends of the developing roll 102 in the axial direction via the sealing members 126. However, when using a developer with poor fluidity, Due to the shape of this side block 127, the developing roll 10
A problem has arisen in that the adsorption of the developer at both ends of 2 is not stable.

According to the inventors' experiments and observations using a conventional developer, this is because the developer scraped off by the trimmer 104 at both ends of the developing roll 102 rubs against the side blocks 127. This is because the flow of developer near the block 127 tends to be stagnant. Therefore, in the developing device of the first embodiment, in order to solve the above problems, the first
As shown in FIG. 9, the end of the side block 127 is cut out diagonally, so that the developer that comes into sliding contact with the side block 127 is diffused toward the inner wall of the housing 101.

As a result, the developer in the vicinity of the side block 127 can now flow smoothly, and a recorded image can be formed with a uniform density over the entire area in the axial direction.

The developer uniformly adsorbed onto the developing roll 102 in the above manner is removed by the trimmer 104 disposed between the transport pole S3 and the transport pole N3, so that the height of the magnetic brush is increased. However, since the developer magnetic brush lies along the lines of magnetic force between the poles, the height of the magnetic brush on the transport pole N3 is not necessarily the same as that between the trimmer 104 and the developing roll 102. does not match the gap. Therefore, from the viewpoint of more accurately controlling the height of the magnetic brush by pA, as shown in FIG. It is preferable that after the height of the spike is regulated at step 104, it is regulated again using the second trimmer 104'.

The developer whose layer thickness has been regulated in this way enters the development area and develops the second latent image formed on the photosensitive drum 70, completing one cycle of developer circulation in the second developing device 100. ends.

In the first embodiment, a sealing member is provided between the developing roll 102 and the tracking roll 123 to prevent floating toner from adhering to the tracking roll 123. However, as shown in FIG. A similar effect can be obtained by providing a fan 123a inside the developer roll 123 and blowing weak air in the direction of the developing roll 102 as the fan 123a rotates.

According to this method, it is also possible to reduce costs by eliminating the need for a sealing member.

■． Summary As described above, the second developing device of this embodiment has various structural features that correspond to poor fluidity of the developer used in the FX microtoning method, and meets the basic functions required of the developing device. In other words, it is possible to smoothly collect the developer from the development area, stir the developer, and supply the developer to the development area, and also eliminates unevenness in water flow caused by poor fluidity of the developer, and improves the electrostatic potential. A toner image that faithfully corresponds to the image can be formed on the photosensitive drum.

Further, using the second developing device 100 configured in this way, F
By performing development using the X microtoning method, the digital color copying machine of this embodiment can produce a high-quality second toner image without disturbing the first toner image formed by the first developing device 80. These toner images can be formed on the photosensitive drum 70, and by collectively transferring these toner images onto a recording sheet, a high-quality recorded image can be obtained by a superposition development method.

[Effects of the Invention] As explained above, according to the development assembly number of the present invention,
Structural features to deal with poor developer fluidity are installed in various parts of the device, including the supply of developer to the developer carrier, the separation of developer from the developer carrier, and the separation of developer and replenishment toner. Since the developer flows smoothly in the developing device through mixing and agitation, the electrostatic latent image formed on the latent image carrier can be faithfully developed in accordance with the potential level, resulting in high quality. It is possible to obtain recorded images.

In addition, by configuring a multicolor image forming apparatus using the overlapping development method using this developing device, even when the second and subsequent developing means are an FX microtoning magnetic brush development method, the first development It is possible to form second and third toner images with uniform density without disturbing the first toner image formed by the method, and it is possible to obtain high-quality multicolor recorded images using the overlapping development method. It is.

Further, according to the developing device of the present invention, the circulation of the developer is performed smoothly even in the developing device having a horizontal structure, and it is possible to form a high-quality toner image with no uneven depth. In configuring this, it becomes possible to save space for installing a developing device around the latent image carrier, and a multicolor image forming apparatus using the overlapping development method can be configured more compactly.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a developing device according to claim 1 of the present invention, FIG. 2 is a schematic configuration diagram showing another developing device that can expect the same effects as the developing device according to claim 1, and FIG. The figure is a schematic configuration diagram showing a developing device according to claims 2 and 3 of the present invention, FIG. 4 is a schematic configuration diagram showing an auger in the developing device according to claim 4 of the present invention, and FIG. FIG. 6 is a schematic diagram showing the auger in the developing device according to claim 5, FIG. 6 is a schematic diagram showing the developing @ position according to claim 7, and FIGS. 7 and 8 are the developing device according to claim 7. FIG. 9 is a perspective view showing a first embodiment of an electrophotographic copying machine to which the developing device of the present invention can be applied, and FIG. FIG. 9 is a schematic diagram of the electrophotographic copying machine, FIGS. 11 and 12 are block diagrams showing an outline of the circuit configuration of the electrophotographic copying machine according to the first embodiment, and FIG. 13 is a schematic diagram of the electrophotographic copying machine according to the first embodiment. FIG. 14 is an explanatory diagram showing the image forming process of the electrophotographic copying machine according to the first embodiment, and FIG. 15 is an enlarged sectional view showing the main parts of the electrophotographic copying machine according to the first embodiment. 16 and 17 are enlarged views showing the main parts of the beam tract mechanism; FIG. 18 is a sectional view showing the first embodiment of the second developing device to which the present invention is applied; FIG. 19 20 shows a plan view of the second developing device according to the first embodiment, FIG. 20 is a side view (partially a sectional view) showing the auger of the second developing device, and FIG. 21 shows a catch of the second developing device. Fig. 22 is an enlarged view of the main parts showing the arrangement position of the kick-up roll in the second developing device, and Fig. 23 is a method of supporting the auger in the second developing device. - Enlarged view of main parts, Part 2
4(a) and 4(bHc) are explanatory views explaining the flow direction of the developer peeled off from the developing roll, respectively. FIG. 25 is a sectional view showing another embodiment of the second developing device, and FIG. 27 is a sectional view showing another embodiment of the paddle wheel of the developing device; FIG. 28 is a sectional view showing a second embodiment of the auger of the second developing device; FIG. 29 Figure 30 shows an example of making a plate-like member from a piece of metal, and Figure 30 shows the second example.
A perspective view showing a state in which the plate member shown in FIG. 9 is attached to an auger,
FIG. 31 is an explanatory diagram showing the vertically installed state of the back plate in the second developing device, FIG. 32 is an enlarged sectional view showing an example in which a second trimmer is added to the second developing device, and FIG. 33 is an explanatory diagram showing the vertically installed state of the back plate in the second developing device. A third perspective view showing an example of the tracking roll in the device.
Figure 4 is a schematic cross-sectional view showing a conventional developing device using the magnetic brush developing method, Figure 35 is a schematic configuration diagram showing an example of the overlapping developing method, and Figure 36 shows one of the problems with the conventional developing device. FIG. 31 is a front view showing an auger in a conventional developing device. [Description of symbols] 101: Housing 102: Developing roll (developer carrier) 103: Wi stirring means 1◇4: Trimmer (trimming plate) 105: First auger 1o6: Second auger 110: Plate member 111: Partition Plate 114: Paddle wheel 115: Back plate 116: Catch-up roll

Claims (8)

[Claims] (1) A developer carrier that has multiple magnetic poles and attracts developer according to the magnetic field formed between each magnetic pole, and peels off the developer after conveying the developer along a predetermined path including the development area. 1 and a stirring means 2 for mixing and stirring the developer peeled off from the developer carrier 1 and the replenishment toner and supplying the agitated developer to the developer carrier 1. A guide surface 11 having a predetermined gap with the developer carrier 1 is provided along the developer conveyance path 6 on the downstream side of the area, and after being conveyed along this guide surface 11. A developing device characterized in that a guide surface 12 for guiding the developer peeled off from the developer carrier 1 to the stirring means 2 is provided so as to intersect with one end of the guide surface. (2) A developer carrier that has multiple magnetic poles and attracts developer according to the magnetic field formed between each magnetic pole, and peels off the developer after conveying the developer along a predetermined path including the development area. 1 and a first screw auger 21 which can transport the developer in the axial direction by rotation, are provided behind the developer carrier 1, and a partition plate 13 having openings 14 and 15 formed at both ends allows the It has one or more screw augers 22 separated from the first screw auger 21, and mixes and stirs the developer peeled off from the developer carrier 1 and replenishment toner, and carries the developer after stirring. In the developing device, the agitating means 2 is located at the downstream side of the first screw auger 21 in the developer conveying direction among the openings 14 and 15 provided at both ends of the partition plate 13. A developing device characterized in that, where the opening width of the opening 14 is A and the opening width of the opening 15 located on the upstream side is B, the opening width is formed so as to satisfy the relationship A>B. (3) The developing device according to claim 2, wherein the openings 14 and 15 provided in the partition plate 13 are opened outside the developable area of the developer carrier 1. (4) A developer carrier that has a plurality of magnetic poles and attracts developer according to the magnetic field formed between each magnetic pole, and peels off the developer after conveying the developer along a predetermined path including the development area. 1 and a first screw auger 21 which can transport the developer in the axial direction by rotation, are provided behind the developer carrier 1, and a partition plate 13 having openings 14 and 15 formed at both ends allows the It has one or more screw augers 22 separated from the first screw auger 21, and mixes and stirs the developer peeled off from the developer carrier 1 and replenishment toner, and converts the agitated developer into a developer. In a developing device including a stirring means 2 for supplying the carrier 1, at least the first screw auger 21 rotates so as to face the partition plate opening 14 located on the downstream side in the developer conveyance direction. Plate member 23 erected on shaft 21a
A developing device comprising: (5) A developer carrier that has multiple magnetic poles and attracts developer according to the magnetic field formed between each magnetic pole, and peels off the developer after conveying the developer along a predetermined path including the development area. 1 and one or more screw augers capable of conveying the developer in the axial direction by a spiral blade 21b provided on the rotating shaft 21a, and mixes and stirs the developer peeled off from the developer carrier 1 and replenishment toner. In the developing device, each screw auger of the stirring means 2 has a developer pressing surface of the spiral blade 21b facing the rotating shaft 21a. A developing device characterized by being erected at an angle. (6) The developing device according to claim 5, wherein a plurality of spiral blades 21b are wound alternately around the rotating shaft 21a, thereby making the developer pressing surface of the spiral blade 21b stand upright. (7) A developer carrier that has a plurality of magnetic poles and attracts developer according to the magnetic field formed between each magnetic pole, and peels off the developer after conveying the developer along a predetermined path including the development area. 1, a stirring means 2 for mixing and stirring the developer peeled off from the developer carrier 1 and replenishment toner, and supplying the agitated developer to the developer carrier 1; A trimming plate 3 is arranged to maintain a gap and equalizes the layer thickness of the developer being conveyed, and a trimming plate 3 is provided with a predetermined interval from the developer carrier 1 and the trimming plate 3 in the axial direction thereof. A developing device characterized in that it is provided with a back plate 4 which is arranged in parallel and together with these back plates 4 forms an auxiliary adsorption area in which the developer peeled off from the developer carrier 1 by the trimming plate 3 is filled and flows. Device. (8) The developing device according to claim 7, wherein the trimming plate 3 and the back plate 4 are integrally constructed.