JP2000056549A - Developing device and image forming device having the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image of an always stable density by regulating the amount by which a developer is supplied to a developer carrier. SOLUTION: In an image forming device having a developer container 4a storing a toner, a freely rotating developing sleeve 5 carrying the toner, an antenna member 8 provided within the developer container 4a in such a way as to be parallel to the direction of the axis of the developing sleeve 5 and adapted for detecting the amount of the toner in the developer container 4a, and a freely rotating agitating member 1 having a rotation axis parallel to the direction of the axis below the antenna member 8, the agitating member 1 satisfies a formula 0.15<=Δx/D<=0.4 where D is the diameter of the rotation space of the agitating member 1 and Δx is the difference between the maximum and minimum values of the distance between the agitating member 1 and the antenna member 8 when the agitating member 1 rotates about the rotation axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for forming an image by an electrophotographic method and an image forming apparatus provided with the developing device.

[0002]

2. Description of the Related Art As a conventional developing device, a developing device using a one-component magnetic toner (hereinafter simply referred to as toner) as a one-component magnetic developer as shown in FIG. 15 is known. Has been offered to.

[0003] Such a developing device, as shown in FIG.
Developing sleeve 105 as a non-magnetic developer carrier formed from a pipe of aluminum, stainless steel, or the like
A magnet 105a fixedly arranged in the developing sleeve 105 and having a plurality of magnetic poles in a circumferential direction as a magnetic field generating means; and an elastic blade formed of urethane rubber, silicone rubber or the like, and serving as a regulating member for regulating the amount of toner on the developing sleeve 105. 107a.

The developing sleeve 105 carries the toner on the surface of the developing sleeve 105 which has been processed to an appropriate surface roughness so that a predetermined toner can be conveyed, is fixed by a support plate 107b, and is pressed against the developing sleeve 105 by a predetermined pressure. The developing sleeve 10 is brought into contact with the elastic blade 107a.
5 is regulated.

The developer regulated on the elastic blade 107a and remaining on the developing sleeve 105
5 is rubbed between the elastic blade 107a and frictionally charged, is given an appropriate charge, and is subjected to development.

In this developing device, the developing sleeve 105 and the antenna member 10 are arranged by the antenna member 108 arranged in parallel to the axial direction of the developing sleeve 105.
8 by using an impedance change due to a change in toner amount between the antenna member 1 and the antenna member 1.
08 to detect the change in current induced in the developer container 104.
The amount of toner in a is estimated.

The developing sleeve 105 is supplied with a developing bias obtained by superimposing an AC bias from a DC power supply 119 on a DC bias from an AC power supply 118 via a sliding contact (not shown).

The comparator 123 includes a diode 12
2 and the capacitance of the capacitor 120 and the diode 12
By comparing the capacitance with the capacitance detected from the antenna member 108 via the antenna 1, it is possible to detect a state where the toner in the developer container does not have a certain amount, and the capacitor 1
Reference numeral 20 has the same capacitance as that of the antenna member 108 when the amount of toner in the developer container is not more than a predetermined amount.

The antenna member 108 is connected to the developer container 104.
a, which is arranged in parallel with the axial direction of the developing sleeve 105 and detects the amount of toner in the developer container 104a.
In particular, since a toner wall is easily formed between the lower portion of the developer container 104a and the antenna member 108 at the lower portion of the antenna member, the stirring member 116 is provided to smoothly supply the toner to the developing sleeve 105 while loosening the toner. It is supposed to.

As shown in FIG. 16, a rod member having a cross section perpendicular to the rotation axis and having a crank shape is used as the stirring member 116.
And rotatably supported in the direction shown in FIG.

The drive for rotating the stirring member 116 is generally utilized by lowering the rotation speed to an appropriate value by a gear train from a drive source of the developing sleeve 150, for example.

[0012]

However, as the particle size of the toner has been reduced in order to improve the reproducibility of one dot of an image and to improve the image quality, such a conventional developing device has been used for a while. In the meantime, the tendency that the image density becomes thin has been observed.

FIG. 17 is a graph showing the difference in toner center particle diameter.
6 is a graph showing a change in image density at the beginning of use. When the average particle diameter is 6 μm and when the average particle diameter is 8 μm, the image density at the beginning of use tends to be low, but the tendency is more remarkable when the central particle diameter is small, and when the central particle diameter is 8 μm or more. In some cases, regarding the low image density at the beginning of use,
I don't care much, but less than that, specifically 7μm
When the following toner particle size is used, it is considered that improvement is at a desirable level.

According to the study by the inventors, the cause of the decrease in image density at the beginning of use due to the small particle size toner is that the toner in the developer container 104a having a relatively small particle size at the beginning of use. Tends to gather near the developing sleeve 105, thereby broadening the tribo-distribution of the toner coated on the developing sleeve 105 (reducing the ratio of toner having an optimum tribo for developing), and developing ability. Was found to have declined.

Since the presence of toner having a small particle size in the developer container 104a poses a problem, it is a phenomenon that the smaller the central particle size of the toner becomes, the more easily the toner particle becomes more noticeable.

Further, it has been found that the above phenomenon becomes more remarkable as a pattern with less toner consumption is continuously printed (for example, solid black immediately after image formation is performed with continuous whitening becomes lighter). This is because the smaller the toner consumption, the larger the amount of fine powder near the developing sleeve 105.

To prevent this problem, it is conceivable to first adjust the particle diameter of the toner (cut the fine powder side at the time of manufacturing). However, the yield at the time of manufacturing the toner is extremely deteriorated, and the cost is increased. It cannot be a realistic hand throw.

Therefore, in order to prevent the fine powder in the toner in the developer container 104a from collecting near the developing sleeve 105, the antenna member 108 in the developer container 104a is minimized.
On the other hand, a method of preventing a large amount of new toner on the side opposite to the developing sleeve 105 from being carried into the vicinity of the developing sleeve 105 can be considered.

FIG. 18 shows a conventional crank type stirring member 11.
6 is a diagram illustrating the movement of toner in a developing device using No. 6; FIG. In the figure, supply of new toner to the developing sleeve 105 is performed through the lower part of the antenna member 108 as shown by an arrow C.

The magnet 10 inside the developing sleeve 105
The toner attracted onto the developing sleeve 105 by the magnetic force 5a is the arrow A or the arrow B except for the toner coated on the developing sleeve 105 by the developer regulating member 107a.
, The flow of toner from the upper portion of the antenna member 108 to the developing sleeve 105 side hardly occurs.

According to the study of the inventors, the space between the agitating member 116 and the antenna member 108 is larger than that of the toner supplied when the agitating member 116 is rotated and pushed in the rotational direction. At that time, the amount of toner flowing into the space was much larger, and it was also found that this large amount of flow caused the initial low density.

That is, in the configuration having the antenna member 116 as in the conventional developing device, the antenna member 11
A configuration is required in which the stirring member 116 provided below the toner supply 6 can optimally control toner supply to the developing sleeve 105 side.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a developing device which regulates the amount of developer supplied to a developer carrying member and always obtains an image having a stable density, and an image forming apparatus provided with the developing device. .

[0024]

According to the present invention, the object is to provide a developer as a one-component magnetic developer to a latent image formed on the latent image carrier. A developer container for housing the developer, a rotatable developer carrier for carrying the developer, and an axial direction of the developer carrier in the developer container. An image forming apparatus comprising: an antenna member provided in parallel with a member for detecting the amount of developer in a developer container; and a rotatable stirring member having a rotation axis parallel to the axial direction below the antenna member. When the stirring member has a diameter D of the rotation space of the stirring member and the difference between the maximum value and the minimum value of the distance to the antenna member when the stirring member makes one rotation around the rotation axis is Δx, 0.15 ≦ Δx / D ≦ 0.4 This is achieved by one invention.

According to the present application, according to the above object,
In the first aspect, the stirring member is also achieved by the second aspect in which the developer in the developer container is agitated when the developing device is performing the developing process.

Further, according to the present application, the above object is to provide an image forming apparatus for recording an image formed by a series of image forming processes on a recording medium, which is provided with a developing device of the first invention. The invention is also achieved by the invention of (1).

According to the present application, the above object is achieved according to the third aspect of the present invention by the fourth aspect of the present invention which comprises a detachable process cartridge for holding the latent image carrier and the developing device of the first aspect. Is also achieved.

Further, according to the present application, the above object is achieved by any one of the third to fourth inventions, wherein the agitating member is provided in the developing container when the developing device is performing the developing process. This is also achieved by the fifth invention in which the agent is agitated.

That is, according to the first aspect of the present invention, the stirring member stirs the developer below the antenna member and regulates the space formed by the antenna member and the stirring member. The amount of the developer carried on the developer carrier passing below the antenna member is regulated to an appropriate amount.

In the second invention according to the present application, the stirring member stirs the developer below the antenna member when the developing device performs the developing process, and forms the stirring member by the antenna member and the stirring member. By regulating the space, the amount of the developer carried on the developer carrier passing below the antenna member is regulated to an appropriate amount.

Further, in the third invention according to the present application, the stirring member stirs the developer below the antenna member and regulates a space formed by the antenna member and the stirring member. The amount of the developer carried on the developer carrier passing below the antenna member is regulated to an appropriate amount.

In the fourth aspect of the present invention, the stirring member stirs the developer below the antenna member and regulates a space formed by the antenna member and the stirring member. The amount of the developer carried on the developer carrier passing below the antenna member is regulated to an appropriate amount.

Further, in the fifth invention according to the present application, the agitating member agitates the developer below the antenna member when the developing device performs the developing process, and is formed by the antenna member and the agitating member. By regulating the space, the amount of the developer carried on the developer carrier passing below the antenna member is regulated to an appropriate amount.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

(First Embodiment) FIG. 1 is a schematic sectional view showing a schematic configuration of an image forming apparatus 100 as an example of the first embodiment of the present invention.

In the image forming apparatus 100, as shown in FIG. 1, a photosensitive drum 11 serving as a cylindrical latent image carrier on which an electrostatic latent image is formed on an outer peripheral surface, and an outer peripheral surface of the photosensitive drum 11 are regulated to a specified potential. A developing device for forming an electrostatic latent image by exposing the outer peripheral surface charged to a specified potential by exposure, and a developing device for visualizing the electrostatic latent image with a developer 4, a roller-shaped transfer device 10 for transferring a visible image (visible image) formed on the outer peripheral surface to a transfer material 14 as a sheet-shaped recording medium, and a fixing device 15.

The photosensitive drum 11 rotates in one direction about a cylindrical shaft. After the surface of the photosensitive drum 11 is uniformly charged by the charging device 3, a latent image is formed by the exposure device 2. You.

The latent image formed on the photosensitive drum 11 is visualized by supplying a developer 9 by the developing device 4.

On the other hand, the transfer material 14 is fed by a feed roller 16 and is transferred to a photosensitive drum 1 by a registration roller (not shown).
The image is sent to the transfer device 10 in synchronization with the image on the first image.

The latent image on the photosensitive drum 11 visualized by the developer 9 as described above is transferred to the transfer material 1 by the transfer device 10.
4 is transferred.

The developer 9 transferred to the transfer material 14
Is transferred to a fixing device 15 together with the transfer material 14 and fixed by heat or pressure to become a recorded image.

On the other hand, the photosensitive drum 11 is not transferred after the transfer.
The remaining developer is removed by a cleaning device 12 having a blade 13.

Thereafter, the surface of the photosensitive drum 11 is charged again by the charging device 3, and the above-described steps are repeated.

FIG. 2 is a schematic sectional view showing a schematic structure of the developing device 4 provided in the image forming apparatus of the present embodiment.
FIG. 3 is a perspective view showing a stirring member provided in the developing device 4 of FIG.

A feature of the present invention lies in the shape of the stirring member 1 disposed below the antenna member 8 for detecting the remaining amount of toner in the developer container.

A developer container 4a for containing the developer, a developing sleeve 5 as a rotatable developer carrier for holding the developer, and a developer sleeve 4a are provided in the developer container 4a in parallel with the axial direction of the developing sleeve 5. An antenna member 8 for detecting the amount of the developer in the developer container 4a, and a rotatable stirring member 1 having a rotation axis parallel to the axial direction below the antenna member 8 are provided.

The stirring member 1 has a diameter D of the rotation space of the stirring member 1, and calculates the difference between the maximum value and the minimum value of the distance from the antenna member 8 when the stirring member 1 makes one rotation around the rotation axis. When Δx is set, 0.15 ≦ Δx / D ≦ 0.4.

The stirring member 1 has a shape in which both ends are bent in a cross section perpendicular to the axial direction, and rotates in the direction shown in FIG. 2 around the center of the shape as the center of rotation. With respect to the developer container 4a, for example, a shape like a constricted portion 1a is provided at both ends in the axial direction, and the constricted portion 1a is provided on a bearing portion (not shown) provided on the developer container 4a side. ) May be arranged rotatably by inserting it into the bracket, but it is not necessary to be limited to this. In addition, the stirring member 1
Is preferably a non-magnetic sheet metal or resin molded product.

The developing sleeve 5 is a φ16 non-magnetic aluminum sleeve, the surface of which is coated with a resin layer containing conductive particles.

The developing sleeve 5 has a magnet roll 5a, which is fixedly arranged in the developing sleeve 5 and has a magnetic field generating means having four magnetic poles in the circumferential direction.

The regulating blade 7a is made of silicone rubber having a JIS hardness of about 40 ° and has a contact force on the developing sleeve 5 of 30 to 40 gf / cm (a contact load per 1 cm with respect to the axial direction of the developing sleeve 5). It is arranged to be.

As the toner, a negatively chargeable magnetic one-component toner is used. The components are 100 parts by weight of a styrene n-butyl acrylate copolymer as a binder resin, 80 parts by weight of magnetic particles, and a monoazo iron complex. 2 parts of a negative charge control agent and 3 parts of a low molecular weight polypropylene as a wax are melt-kneaded with a biaxial extruder heated to 140 ° C., and the cooled kneaded material is coarsely pulverized by a hammer mill, and the coarsely pulverized material is jet-milled. Finely pulverized, the obtained finely pulverized material is subjected to air classification to obtain a classified powder having a weight average diameter of 5.0 μm. 1.0 part by weight of hydrophobic silica fine powder is mixed with a classified product having an average particle size of 5.0 μm using a Henschel mixer to obtain a developer. The weight average particle size is in the range of 3.5 to 7.0 μm (mainly 6 to 7.0 μm).
μm) is used.

A bias power supply (not shown) in which an AC bias is superimposed on a DC bias is connected between the photosensitive drum 11 and the developing sleeve 5a so as to apply an appropriate developing bias.

For example, when the gap between the photosensitive drum 11 and the developing sleeve 5 is about 300 μm, the developing bias applied to the developing sleeve 5 is DC voltage: −5.
00 V, AC voltage: rectangular wave Vpp 1600, frequency 22
00 Hz is applied.

After the photosensitive drum 11 is charged to Vd = −600 V by the charging device 3 on the photosensitive drum 11, the portion exposed by the exposure device 2 becomes Vl = −150 V, and the portion exposed to Vl is inverted. Developed.

According to the present embodiment, by effectively controlling the supply of the toner to the developing sleeve 5 side, the developer container 4 on the side opposite to the developing sleeve 5 with respect to the antenna member 8 is formed.
It is possible to prevent a phenomenon in which the image density at the beginning of use becomes thin (hereinafter referred to as an initial image density thinning phenomenon) due to a large amount of new toner flowing in the area a.

FIGS. 4 and 5 show the positional relationship between the stirring member 1 and the antenna member 8 in this embodiment. FIG. 4 shows that the stirring member 1 makes one rotation about the rotation axis of the stirring member 1. In this case, FIG. 5 is a schematic side view showing a state where the stirring member 1 is farthest from the antenna member 8, and FIG.
Is a schematic side view showing a state in which the antenna is closest to the antenna member 8.

When the stirring member 1 has this shape, the maximum distance from the antenna member 8 to the stirring member 1 is Xmax in the state shown in FIG. 4, and the arc S is formed by the rotation of the stirring member 1. The diameter of the rotating space is D, and as shown in FIG.
Is closer to the antenna member 8, and the minimum distance from the antenna member 8 to the stirring member 1 is Xmin.

On the other hand, FIGS. 6 and 7 show the positional relationship between the agitating member 116 having the same crank shape as the conventional example and the antenna member 8. After one rotation around the axis, FIG.
7 shows a state where the stirring member 116 is farthest from the antenna member 8, and FIG. 7 shows a state where the stirring member 116 is closest to the antenna member 8.

According to the stirring member 1 of this embodiment, as shown in FIGS. 6 and 7, a conventional crank-shaped stirring member 1 is used.
It can be seen that the maximum value Xmax of the distance from the antenna member to the stirring member is smaller than the maximum value X16.

That is, the effect of the present invention is to prevent a large amount of new toner from flowing by forming a stirring shape that keeps the distance from the antenna member to the stirring member small.

Next, the results of further studies by the inventors on other stirring member shapes that can keep the distance from the antenna member to the stirring member small will be described.

For convenience of explanation in the future, Xmax and Xmin
Δx, and the state (form) of the distance from the antenna member to the stirring member is represented by Δx / D.

The Δx / D value indicates the ratio of the change in the distance from the antenna member to the stirring member (the swing width of the rotation space due to the rotation of the stirring member) with respect to the diameter of the rotation space of the stirring member. The shape of the stirring member is close to a circle, and when the value is 0, the shape is a perfect circle. Also, it is considered that the smaller the value is, the higher the effect of preventing the inflow of toner is, so that the phenomenon of low initial image density is likely to occur.

However, if the Δx / D value is too small, the toner supply force to the developing sleeve side is reduced, which may cause a phenomenon of fading in which a part of a black-and-white image is missing.

The following is a result of a study conducted by the inventors on an appropriate stirring member shape which does not cause any adverse effect as a measure for reducing the initial concentration.

As shown in FIG. 8, the initial image density thinning phenomenon was examined for several types of agitating members having different cross-sectional shapes perpendicular to the axial direction of the agitating member (hereinafter, referred to as agitating shapes).

The stirring shape a was a shape obtained by cutting a part of a circle on four planes, the stirring shape b was a square, and the stirring shape C was a regular triangle. In each case, a molded resin product was used.

The stirring shape d is the same shape as the stirring member 1 in this embodiment, and the stirring shape e is a flat plate shape. These are formed by processing non-magnetic SUS. The developing device and the image forming device used in this experiment are the same as those described above. The detailed experimental conditions are as follows.

(Experimental Conditions) Experimental environment: temperature 23 ° C., humidity 60% Process speed of image forming apparatus: 80 mm / sec Diameter of antenna member: φ2.0 Distance between lower part of antenna member and rotation center of stirring member: 6.0 m
m Stirring member rotation space diameter (D): 6.5 mm Rotation speed of stirring member: 35 rpm (Experimental method) First, in a developing device incorporating each stirring member,
In order to increase the amount of fine powder near the developing sleeve and make the initial image density light, ten blank images are output. 2. Next, in order to confirm the effect on the initial low density, one black sheet is taken out and the image density is measured. The density was measured using a Macbeth reflection densitometer (manufactured by Macbeth). 3. In order to judge the effect based on the amount of fine powder that is directly responsible for the low density, 10 solid white images are output again, and then a toner sample on the developing sleeve is collected. Measure. The particle size of the toner was measured using a coal tar multi-riser (manufactured by Coal Tar) 3.2.
Those having a particle size of μm or less are judged to be fine powder, and the ratio is calculated. In the toner used in this experiment, the content of fine powder having a particle size of 3.2 μm or less at the time of production was about 13%. 4. Thereafter, 30 solid black sheets are taken out, and the presence / absence of fading and the degree thereof are determined by referring to a sample to determine the presence / absence of fading.

The results are shown in the table of FIG.
As shown in FIG. 9, it can be seen that as the value of Δx decreases, the amount of fine powder that causes the initial image density thinning phenomenon also occurs, and the image density increases accordingly. However, in the stirring member having the shape of Δx of 0.12, a slight fading phenomenon was observed. Therefore, in order to prevent the fading phenomenon from occurring, it is desirable to set the value of Δx to 0.1 S or more.

Further analysis will be made on the phenomenon of low initial image density. FIG. 10 is a graph showing the relationship between the fine powder amount and the initial image density, and FIG. 11 is a graph showing the relationship between Δx / D and the fine powder amount.

First, as shown in FIG.
%, The image density suddenly decreases. Therefore, considering the performance stability, the amount of fine powder is 20%.
The following suppressed stirring shapes are preferred. As shown in FIG. 11, when examining the shape for suppressing the amount of fine powder to 20% or less,
It is understood that the value of x is preferably 0.4 or less.

Therefore, the optimum shape of the stirring member capable of reducing the initial image density without a problem is 0.15 ≦ Δx / D ≦ 0.
It turned out to be 4.

The shape of the stirring member applied to the present embodiment is not limited to the shape shown in FIG. 8, but may be a shape satisfying 0.15 ≦ Δx / D ≦ 0.4 from the state when rotated. Needless to say, they all fit.

Therefore, according to the present embodiment, the stirring member 1
Stirs the toner below the antenna member 8 and regulates the space formed by the antenna member 8 and the stirring member 1 so that the amount of toner carried on the developing sleeve 5 under the antenna member 8 can be adjusted by an appropriate amount. , The amount of toner carried on the developing sleeve 5 is stabilized, a large amount of toner is prevented from accumulating in the vicinity of the developing sleeve 5, and an image having a stable density is always obtained from the start of use. Can be.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. 13 or FIG. The same components as those of the image forming apparatus according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

This embodiment is characterized in that, in the image forming apparatus of the first embodiment, the developing device 4 is
Integrated type cartridge 6 as a detachable process cartridge holding cleaning device 12 and charging device 3
(Hereinafter referred to as cartridge 6).

FIG. 13 is a diagram showing the cartridge 6. FIG.
It is a figure showing the situation when it is inserted into the 00 main body.

In the present embodiment, since the developing device 4, the photosensitive drum 11, the cleaning device 12, and the charging device 3 are integrated to form an integrated cartridge, when the toner 109 is used up, the other devices almost end their lives at the same time. It is designed to be. Therefore, there is an advantage that the user can always obtain a stable image while the toner in the cartridge 6 is present, and since it is of the integral type, it can be easily replaced.

By using the stirring member of the present invention for the developing device in the cartridge, it is possible to obtain an advantage that a stable concentration can be obtained from the beginning, in addition to the inherent advantages of the integrated cartridge.

Therefore, according to the present embodiment, the stirring member 1
Stirs the toner below the antenna member 8 and regulates the space formed by the antenna member 8 and the stirring member 1 so that the amount of toner carried on the developing sleeve 5 under the antenna member 8 can be adjusted by an appropriate amount. , The amount of toner carried on the developing sleeve 5 is stabilized, a large amount of toner is prevented from accumulating in the vicinity of the developing sleeve 5, and an image having a stable density is always obtained from the start of use. Can be.

According to the present embodiment, the image forming apparatus 1
By providing the detachable cartridge 6 that holds the developing device 4, the photosensitive drum 11, the cleaning device 12, and the charging device 3, the maintenance such as toner replacement and repair can be easily performed.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIG. 14 of the accompanying drawings.
The same components as those of the image forming apparatus according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The feature of this embodiment is that, in the image forming apparatus of the first embodiment, the operation of the stirring member 1 is limited only to the time when the developing device is performing the developing process (during the developing operation).

In a conventional general image forming apparatus,
Since the stirring member in the developing device is driven by the drive from the main motor in the main body of the image forming apparatus, the stirring member is moved while the main motor is driven.

Incidentally, the phenomenon of low initial concentration, which is a problem in the present invention, is a phenomenon in which fine particles in the toner tend to collect near the developing sleeve as the stirring member continues to move. Accordingly, in the developing device or the image forming apparatus using the stirring member of the present invention, it is more effective to stop the movement of the stirring member as much as possible except for the developing operation in order to prevent the initial density from becoming low.

FIG. 14 is a timing chart that best illustrates the features of this embodiment.

In the present embodiment, the on / off of the driving of the stirring member
The off timing is matched with the on / off timing of the developing bias.

In the present embodiment, it is necessary to make the drive of the stirring member 1 independent of the drive system of the main motor (not shown). For example, a method in which a drive unit of the stirring member 1 is made independent by providing a clutch, a method in which a drive source dedicated to the stirring member is provided, and the like are included, but the present invention is not limited thereto.

Thus, according to the present embodiment, the stirring member 1
Stirs the toner below the antenna member 8 and regulates the space formed by the antenna member 8 and the stirring member 1 so that the amount of toner carried on the developing sleeve 5 under the antenna member 8 can be adjusted by an appropriate amount. , The amount of toner carried on the developing sleeve 5 is stabilized, a large amount of toner is prevented from accumulating in the vicinity of the developing sleeve 5, and an image having a stable density is always obtained from the start of use. Can be.

According to the present embodiment, the stirring member 1 is
Since the toner in the developer container 4a is agitated during the developing process of the developing device, the amount of the developer supplied to the developing sleeve 5 from below the antenna member can be further regulated, and The amount of toner carried on the sleeve 5 is stabilized, so that a large amount of toner is prevented from collecting near the developing sleeve 5, and an image having a stable density can be always obtained from the start of use.

[0093]

As described above, according to the first aspect of the present invention, the stirring member stirs the developer below the antenna member, and the space formed by the antenna member and the stirring member. By regulating, the amount of the developer carried on the developer carrying member under the antenna member is set to be regulated appropriately, so that the amount of the developer carried on the developer carrying member is stabilized, A large amount of developer is prevented from accumulating in the vicinity of the developer carrier, and an image having a stable density can be always obtained from the start of use.

According to the second invention of the present application,
The stirring member stirs the developer below the antenna member when the developing device performs the developing process, and regulates a space formed by the antenna member and the stirring member. Since the amount of the developer carried on the carrier is set to be regulated to an appropriate amount, the amount of the developer carried on the developer carrier is stabilized, and a large amount of the developer is accumulated near the developer carrier. Thus, an image with a stable density can always be obtained from the start of use.

Further, according to the third aspect of the present invention, the stirring member stirs the developer below the antenna member and regulates the space formed by the antenna member and the stirring member, thereby providing the antenna with the antenna. Since the amount of the developer carried on the developer carrying member under the member is set to be regulated to an appropriate amount, the amount of the developer carried on the developer carrying member is stabilized, and the amount of the developer carried on the developer carrying member becomes stable near the developer carrying member. It is possible to prevent the developer from being accumulated in a large amount, and to obtain an image having a stable density from the beginning of use.

According to the fourth invention of the present application,
The stirring member stirs the developer below the antenna member and regulates a space formed by the antenna member and the stirring member, so that the amount of the developer carried on the developer carrying member below the antenna member is reduced. It is set to regulate to an appropriate amount, so the amount of developer carried on the developer carrier is stable, preventing a large amount of developer from accumulating near the developer carrier, and a stable concentration from the beginning of use. Image can be obtained.

Further, according to the fifth aspect of the present invention, the stirring member is formed by the antenna member and the stirring member while stirring the developer below the antenna member when the developing device performs the developing process. Is regulated so as to regulate the amount of developer carried on the developer carrier by passing under the antenna member to an appropriate amount.
The amount of the developer carried on the developer carrier is stabilized, and it is possible to prevent a large amount of developer from being accumulated near the developer carrier, and to obtain an image having a stable density at all times from the start of use.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view illustrating a schematic configuration of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a schematic configuration of a developing device provided in the image forming apparatus of FIG.

FIG. 3 is a perspective view of a stirring member provided in the developing device of FIG. 2;

FIG. 4 is a diagram illustrating a state in which a stirring member and an antenna member according to the first embodiment of the present invention are farthest from each other.

FIG. 5 is a diagram illustrating a state in which the stirring member and the antenna member according to the first embodiment of the present invention are closest to each other.

FIG. 6 is a diagram showing a state in which a stirring member and an antenna member in the related art are farthest from each other.

FIG. 7 is a diagram illustrating a state in which a conventional stirring member and an antenna member are closest to each other.

FIG. 8 is a cross-sectional view perpendicular to the axial direction of a stirring member studied in an experiment in the first embodiment of the present invention.

FIG. 9 is a table showing the results of an experiment performed with the stirring member of FIG. 9;

FIG. 10 is a graph showing a relationship between a fine powder amount of a developer and an initial image density in an experiment in the first embodiment of the present invention.

FIG. 11 shows Δ in an experiment in the first embodiment of the present invention.
It is a graph which shows the relationship between x / D and fine powder amount.

FIG. 12 is a schematic sectional view illustrating a schematic configuration of an image forming apparatus according to a second embodiment of the present invention.

13 is a schematic cross-sectional view illustrating a schematic configuration of a process cartridge provided in the image forming apparatus of FIG.

FIG. 14 is a timing chart showing the operation timing of the stirring member according to the third embodiment of the present invention.

FIG. 15 is a schematic sectional view showing a schematic configuration of a conventional developing device.

16 is a diagram illustrating a stirring member provided in the developing device of FIG.

17 is a graph showing a change in toner particle diameter and an initial image density in the developing device of FIG.

FIG. 18 is a diagram illustrating movement of a developer in a developer container in a conventional developing device.

[Explanation of symbols]

 Reference Signs List 1 stirring member 4 developing device 4a developer container 5 developing sleeve (developer carrier) 6 integrated cartridge (process cartridge) 8 antenna member 9 toner (developer) 100 image forming apparatus

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsutoshi Ando 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Ken Sunahara 3-30-2 Shimomaruko 3-chome, Ota-ku, Tokyo 2H077 AA35 AB01 BA09 DA15 DA42 DA58 DB02 EA13 GA04

Claims (5)

[Claims] A developing device for visualizing the latent image by applying a developer, which is a one-component magnetic developer, to the latent image formed on the latent image carrier by the developer carrier. A developer container for storing the developer, a rotatable developer carrier for carrying the developer, and an amount of the developer in the developer container provided in the developer container in parallel to the axial direction of the developer carrier. In an image forming apparatus having an antenna member for detecting the rotation and a rotatable stirring member having a rotation axis parallel to the axial direction below the antenna member, the stirring member has a diameter of the rotation space of the stirring member of D. When the difference between the maximum value and the minimum value of the distance from the antenna member when the stirring member makes one rotation around the rotation axis is Δx, 0.15 ≦ Δx / D ≦
0.4. 2. The developing device according to claim 1, wherein the stirring member stirs the developer in the developer container when the developing device is performing a developing process. 3. An image forming apparatus for recording an image formed by a series of image forming processes on a recording medium, comprising the developing device according to claim 1. 4. The image forming apparatus according to claim 3, further comprising a detachable process cartridge for holding the latent image carrier and the developing device according to claim 1. 5. The image forming apparatus according to claim 3, wherein the stirring member stirs the developer in the developer container when the developing device is performing the developing process. apparatus.