JPH07181804A - Developer regulating member, developing device, image forming device and process cartridge - Google Patents

Abstract

PURPOSE:To suppress the electric power consumption and power source cost by impression of a vibration voltage to a lower level at the time of impressing the vibration voltage between an electrode disposed on a developer regulating member pressed onto a developer carrying member and this developer carrying magnetic one-component developer on the developer one-component developer on the developer carrying member and the regulating member to move the developer back and forth so as to prevent the unequal electrostatic charge, unequal coating and opposite polarity electrostatic charge. CONSTITUTION:The width W in a direction perpendicular to the longitudinal direction of a blade of the electrode 4 for impressing the vibration voltage of an elastic blade to be pressed to a developing sleeve is set to be 0.3 to 2mm. As a result, the electrostatic capacity between the blade and the developing sleeve decreases and the current quantity flowing between the electrode 4a and the developing sleeve decreases at the time of impressing the vibration voltage and, therefore, the reduction of the power source cost is attained by the reduction of the electric power consumption and the miniaturization of the power source. The purpose is thus achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine or a page printer, a developing device used therein, a developer regulating member thereof, and a process cartridge incorporating the developing device. .

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic system such as a copying machine or a page printer, a latent image formed on a latent image carrier is developed and visualized as a toner image. A developing device using a magnetic one-component developer is known. An example of an image forming apparatus provided with a developing device using such a developer is shown in FIG.

As shown in the figure, the image forming apparatus has a photosensitive drum 1, and a charging roller 2 is in contact with the photosensitive drum 1. The charging roller 2 has a cored bar 2a covered with a conductive rubber layer 2b in which carbon is dispersed in rubber such as EPDM, and a contact plate 2c connected to a bias power source 14 is brought into contact with the cored bar 2a. There is. A DC voltage is applied to the core metal 2a of the charging roller 2 from the power source 14 via the contact plate 2c, and the surface of the photosensitive drum 1 is uniformly charged by the charging roller 2 to a predetermined potential.

Next, a laser beam 9 facing the time-series electric pixel signals of the image information is output from the illustrated laser scanner to the uniformly charged photosensitive drum 1, and the laser beam 9 is applied to the surface of the photosensitive drum 1. And is sequentially main-scanned in the drum generatrix direction, an electrostatic latent image of image information is formed on the surface of the photosensitive drum 1. The electrostatic latent image is moved to the developing section facing the developing device 5A as the photosensitive drum 1 rotates, is developed by the magnetic toner 6 of the magnetic one-component developer in the developing section, and is visualized as a toner image.

The developing device 5A includes a developing container 5 containing a magnetic toner 6, and an opening of the developing container 5 facing the photosensitive drum 1 is a conductive developing sleeve 3 as a developer carrier.
Have. The magnet 1 is provided inside the developing sleeve 3.
2 is arranged, the magnet 12 holds the toner 6 on the developing sleeve 3, and conveys the toner 6 from the container 5 to the developing portion facing the photosensitive drum 1. The toner on the developing sleeve 3 is regulated by the elastic blade 4 which is a developer regulating member during the conveyance, and is applied on the developing sleeve 3 as a uniform thin toner layer.

The developing sleeve 3 has a developing bias power source 15
Is supplied to the photosensitive drum 1 under the application of a predetermined developing bias to the developing sleeve 3 by the power supply 15 to develop the latent image on the photosensitive drum 1. Toner image. The toner that has not contributed to the development is returned to the developing container 5 by the rotation of the developing sleeve 3 and is collected in the container.

A transfer material 11 is supplied from an unillustrated cassette to an image transfer portion where the photosensitive drum 1 and the transfer roller 10 face each other, and is applied to the transfer roller 10 in the process of passing between the photosensitive drum 1 and the transfer roller 10. The toner image on the photosensitive drum 1 is transferred onto the transfer material 11 by a transfer voltage having a polarity opposite to that of the generated toner.

The transfer material 11 on which the toner image is transferred is then conveyed to a fixing device (not shown), where the toner image is heat-fixed on the transfer material 11 to form a permanent image, and then the transfer material 11 is ejected outside the image forming apparatus. To be done. After the transfer of the toner image, the surface of the photosensitive drum 1 is cleaned and removed by the cleaning blade 7 to remove the transfer residual toner and other contaminants to normalize the surface, and is then subjected to image formation again.

The conventional developing device will be described in more detail. The magnetic toner 6 is conveyed by the magnetic force of the magnet 12 shown in FIG. 8 from the upstream on the right side to the downstream on the left side as the developing sleeve 3 rotates. On the way, it is regulated by the elastic blade 4 which is in contact with the developing sleeve 3, and is uniformly applied in a thin layer on the developing sleeve 3.

The toner 6 applied and carried on the developing sleeve 3 is rubbed with the surface of the developing sleeve 3 and the elastic blade 4 to be triboelectrically charged in the course of being conveyed, and a latent image on the photosensitive drum 1 is obtained. Is used for development.

However, when the toner strongly charged by the above-mentioned frictional charging approaches the developing sleeve 3 and the elastic blade 4, a large electrostatic mirroring force works between them.
Adhere to their surface. Further, the toner adhering to the surface of the developing sleeve or the elastic blade has various physical attraction forces in addition to the electrostatic mirror image force, and cannot be easily peeled off from the surface. Therefore, as shown in FIG. 9, the surfaces of the developing sleeve 3 and the elastic blade 4 are covered with several layers of toner 6,
The toner supplied later hindered contact with the developing sleeve 3 and the elastic blade 4.

When an image having a low printing rate is continuously developed particularly in a low humidity environment, the toner covering the developing sleeve 3 is more strongly charged, resulting in uneven charging of the toner and uneven coating. There was a case where a corresponding uneven image defect occurred.

Further, in the above-described state, not only the charging efficiency of the toner is lowered, but also the frictional electrification between the toners is increased, so that the toner is charged to the opposite polarity (reversed toner).
However, as a result, the image density is lowered and the "fog" in the non-image area is increased, which is a factor of impairing the image quality.

Further, when a part of the toner 6 on the developing sleeve 3 is used for the development, the toner newly carried and charged on the portion of the developing sleeve 3 used for the development and the toner not used for the development. There is a difference in the amount of charge between the toner carried as it is and further charged, and due to the difference in the amount of charge of the toner, the effect of the previous image appears when developing next time (called "ghost") Phenomenon) may occur.

In addition, the developing sleeve 3 and the elastic blade 4
If a foreign matter is caught between the toner and the toner, the application of the toner 6 may be disturbed, but heretofore, there has been no method for effectively alleviating the toner application disturbance.

Therefore, as a measure against these problems, a method has been proposed in which an electrode is provided on the elastic blade 4 and a bias voltage is applied to the electrode. A developing device adopting this method will be described with reference to FIGS.

Elastic blade 4 of the developing device shown in FIG.
Is provided with an electrode 4a made of a conductive material such as carbon-dispersed nylon on the surface of an elastic blade body 4b made of an insulating material such as urethane, and the entire surface of the body 4b, or at least the surface of the body 4b on the developing sleeve 3 side. Is covered with a high resistance layer 4c such as urethane resin. The elastic blade 4 is in contact with the developing sleeve 3 in the direction opposite to the rotating direction.

A bias power source 16 is connected to the electrode 4a so that a predetermined blade bias voltage can be applied. The high resistance layer 4c of the elastic blade 4 is the electrode 4a.
It is provided to prevent leakage between the developing sleeve 3 and the developing sleeve 3.

As described above, the elastic blade 4 is applied with an alternating electric field by the blade bias from the power source 16 between the electrode 4a and the developing sleeve 3, and the charged toner in the meantime is subjected to the alternating electric field. The power according to strength works. When the force due to the alternating electric field exceeds the electrostatic mirroring force acting between the strongly charged toner and the elastic blade 4 or the developing sleeve 3, the alternating electric field E is reversed from the direction of FIG. 11 to the direction of FIG. Then, in the direction from the developing sleeve 3 to the elastic blade 4, the toner layer covering the elastic blade 4 is peeled off, and the toner layer is transferred and removed as the developing sleeve 3 rotates. Therefore, the adverse effect of the contact of the new toner with the developing sleeve 3 and the elastic blade 4 caused by the toner layer and the frictional charging between the toners is eliminated, and the reversal toner is reduced while the charging efficiency of the toner is improved.

Particularly, on the downstream side from the sliding portion between the elastic blade 4 and the developing sleeve 3, the toner 6 reciprocates according to the alternating electric field, as shown in FIG. In this downstream region,
Not only is the toner layer covering the elastic blade 4 or the developing sleeve 3 peeled off, but also the toner flies back and forth, so that the toner layer formed by the overcharged toner layer and the magnetic force is loosened and sufficiently stirred. . Due to this stirring effect, the uneven charging of the toner 6 is almost eliminated. Further, uneven coating caused by foreign matter sandwiched between the elastic blade 4 and the developing sleeve 3 is also alleviated by the stirring effect.

As a matter of course, if the alternating electric field is controlled to be constantly applied during the rotation of the developing sleeve 3, the toner layer covering the elastic blade 4 or the developing sleeve 3 is not formed, and the above-mentioned problem occurs. Absent. Further electrode 4a
When a voltage in which a DC voltage and an AC voltage are superimposed is applied to the toner 6, not only the toner 6 reciprocates between the elastic blade 4 and the developing sleeve 3, but also the charge corresponding to the DC component of the bias applied to the electrode 4a It is injected into the toner on the developing sleeve, and the toner is charged. As a result, it becomes possible to set the charge amount of the toner to a predetermined value,
It has become possible to stably obtain high-quality images free from ghosts, fog, and uneven density.

[0022]

However, the width of the electrode 4a (the length in the direction perpendicular to the longitudinal direction of the elastic blade 4, the longitudinal direction of the elastic blade 4 being the same as the axial direction of the developing sleeve 3), is If it is large, the electrostatic capacitance between the electrode 4a and the developing sleeve 3 will be large, and a large amount of current will flow when the alternating electric field is applied, resulting in large power consumption. Also, since a large current flows, the power supply 1
6 also requires a larger capacity, which is a factor of increasing the product cost of the developing device.

Further, when the width of the electrode 4a is small, it is difficult to position the electrode 4a with respect to the elastic blade 4, which deteriorates the productivity of the developing device.

Further, since the toner charged by the elastic blade 4 and the developing sleeve 3 contains a hygroscopic substance such as carbon or silica as its component, the toner is charged depending on the use environment, especially the humidity of the environment. There was a property that the amount changed. Specifically, an excess charge occurs in a low humidity environment, and an insufficient charge occurs in a high humidity environment, which causes a decrease in concentration.

Therefore, the solution by applying a bias to the elastic blade 4 has an excellent effect on ghost, fog, or uneven density, but when used for a long time under an environment other than the normal environment. In particular, the density was lowered in the latter half, and this point was not sufficient.

An object of the present invention is to apply an oscillating voltage between the developer carrying member and the electrode provided on the developer carrying member which is in contact with the developer carrying member so that the developer carrying member and the carrying member can be restrained. When the developer layer of the above magnetic one-component developer is peeled off and reciprocally moved to prevent uneven charging of the developer, uneven coating of the developer, and opposite polarity charging, the power consumption and power source cost due to the application of the oscillating voltage are kept low. It is an object of the present invention to provide a developer regulating member capable of achieving the above, a developing device including the developer regulating member, a process cartridge incorporating the developing device, and an image forming apparatus.

Another object of the present invention is to stabilize the electrostatic charge of the developer irrespective of the environment in which it is used, to reliably eliminate the excessive charge or insufficient charge of the developer, and to prevent unevenness and fog from forming the density. It is possible to obtain a sufficiently high quality image.

[0028]

The above object is achieved by a developer regulating member, a developing device, an image forming apparatus and a process cartridge according to the present invention. In summary, the present invention, by controlling the magnetic one-component developer carried on the developer carrying member and conveyed to the developing section facing the latent image carrying member, by contacting the developer carrying member and regulating it, In a developer regulating member made of an elastic body that applies a developer layer having a predetermined layer thickness on the developer carrying member, the developer regulating member has an electrode facing the developer carrying member, and the width of the electrode. 0.3mm or more 2m
The developer regulating member is characterized in that it is m or less.
According to the present invention, the volume resistivity of the elastic body of the developer regulating member changes depending on the humidity of the environment.

A developing device according to the present invention comprises the above-mentioned developer regulating member, and an image forming device comprises the developing device.
An oscillating electric field is applied between the developer regulating member and the developer carrying member. The process cartridge according to the present invention,
In a process cartridge that includes at least a developing device and is attachable to and detachable from a main body of an image forming apparatus, the developing device includes the above developing device.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic structural view showing an embodiment of an image forming apparatus of the present invention, and FIG. 2 is an enlarged view of a main part of the developing device. The image forming apparatus of this embodiment is characterized by the developing device 5A, and in particular, the elastic blade 4 is provided with the width of the electrode 4a controlled within a predetermined range. Other configurations of the present embodiment are basically the same as those of the image forming apparatus shown in FIG. 10, and the same reference numerals as those shown in FIG. 10 in FIGS. 1 and 2 denote the same members.

As shown in FIGS. 1 and 2, in the developing device 5A of the present embodiment, the elastic blade 4 has a conductive material such as carbon-dispersed nylon on the surface of the elastic blade body 4b made of an insulating material such as urethane. The electrode 4a made of a material is provided, and the entire surface of the body 4b, or at least the body 4b
The surface on the side of the developing sleeve 3 is covered with a high resistance layer 4c such as urethane resin. The entire elastic blade 4 is attached to the developing container 5 by a supporting member 4d, and is in contact with the developing sleeve 3 in the direction opposite to the rotating direction. The contact of the elastic blade 4 may be in the forward direction which is the same as the rotation direction of the developing sleeve 3.

A blade bias power source 16 is connected to the electrode 4a provided on the elastic blade 4. In order to uniformly supply the vibration voltage applied by the power source 16 in the longitudinal direction of the elastic blade 4 (the same direction as the axial direction of the developing sleeve 3), as shown in the plan view of FIG.
The electrode 4 a has a predetermined width w in the direction perpendicular to the longitudinal direction of the elastic blade 4 and is provided over the longitudinal direction of the elastic blade 4. According to the invention, the width w of this electrode 4a is 0.
It is set to 3 mm or more and 2 mm or less.

In this embodiment, as the magnetic toner 6 which is a magnetic one-component developer, a negatively chargeable toner having a particle diameter of about 6 μm is used, and a developing bias is applied to the developing sleeve 3 as follows: DC voltage: Vdc = -400V AC voltage: Square wave Amplitude Vac = 1.6 kVpp Frequency = 1800 Hz was applied. A DC bias: Vdc = -600V, an AC voltage: a sine wave, an amplitude Vac = 800Vpp, and a frequency = 1800Hz were applied as a blade bias to the electrode 4a so as to be in reverse phase with respect to the developing sleeve.

According to this, the toner 6 in the toner layer on the developing sleeve 3 reciprocates between the elastic blade 4 and the developing sleeve 3 and is agitated. Therefore, uneven charging of toner, uneven coating, and charging of opposite polarity are prevented.

When the width of the electrode 4a is 1 mm, the current I flowing between the electrode 4a and the developing sleeve 3 is I = (Vpp × πfC) / 2 ^1/2, where C is the electrode 4a. The capacitance between the developing sleeves 3 is represented by C = ε × (L × w / r) (where ε: dielectric constant, L: length of electrode 4a, w: electrode 4).
Width of a, r: thickness of toner layer) In this embodiment, ε = 8.85 × 10 ⁻¹² F · m ⁻¹ L = 216 mm and w = 1 mm r = 100 μm. When this is calculated, the electrode 4a and the developing sleeve 3
The current flowing between the two is I≈180 μA.

On the other hand, for example, the width of the electrode 4a is 10 m.
In the case of m, the current flowing between the electrode 4a and the developing sleeve 3 is I≈1.8 mA, which is larger than that in the case where the width of the electrode 4a is 1 mm.

As described above, according to the present invention, since the width of the electrode 4a provided on the elastic blade 4 is set to 2 mm or less, the electrode 4a and the developing sleeve 3 are different from the case where the width of the electrode 4a is wide. Capacitance between and can be kept small. Therefore, the amount of current flowing between the electrode 4a and the developing sleeve 3 can be suppressed to be small, the power supply 16 can be made small, and the cost can be reduced.

In the above, even if the width w of the electrode 4a is set to 2 mm or more, the width of the sliding portion between the developing sleeve 3 and the elastic blade 4 is about 2 mm. Therefore, the stirring effect is large despite the increase in power consumption. I won't. Even if the width w of the electrode 4a is 0.3 mm or less, it is difficult to position the electrode 4a with respect to the elastic blade 4, and the productivity of the developing device is deteriorated and the manufacturing cost is increased.

From the above, in the present invention, the width of the electrode 4a provided on the elastic blade 4 is set to 0.3 mm or more and 2 mm or less. This makes it possible to reduce the manufacturing cost while suppressing the power consumption due to the application of the blade bias to the electrode 4a.

Embodiment 2 FIG. 4 is a schematic diagram showing another embodiment of the developing device of the present invention. In this embodiment, the elastic blade 4 is formed by embedding the electrode 4a in the blade body 4b, and covering the surface of at least the developing sleeve 3 side of the body 4b with the high resistance layer 4c. In this example, hydrin rubber was used for the main body 4b. The other structure of this embodiment is basically the same as that of the first embodiment, and the same reference numerals as those shown in FIGS. 1 and 2 in FIG. 4 denote the same members.

As shown in FIG. 5, the hydrin rubber used for the elastic blade body 4b is used in an environment (external environment).
Has the property that its resistance value (volume resistivity) changes depending on the difference. That is, hydrin rubber has a high resistance value in a low humidity environment and a low resistance value in a high humidity environment.

In this embodiment, when the same developing bias and blade bias as in Embodiment 1 are applied, the interface between the elastic blade 4 and the developing sleeve 3 is equivalent to the circuit shown in FIG. Is considered to be.

Here, the distance between the electrode 4a of the elastic blade 4 and the resistance layer 4c is 1 mm, and the thickness of the resistance layer 4c is 50 μm.
m, the thickness of the thin toner layer is 100 μm, and other conditions are the same as in Example 1, the maximum voltage Vmax applied between the electrode 4a and the developing sleeve 3 is 15 ° C./10.
In a low temperature and low humidity environment (L / L) of% RH, Vmax (L / L) ≈2.1 × 10 ⁶ V / cm, and in a high temperature and high humidity environment (H / H) of 32.5 ° C./85% RH, Vmax (H / H) ≈1.97 × 10 ⁷ V / cm.

The proper range of the maximum value Emax of the voltage that can obtain a sufficient stirring effect and the withstanding pressure of the elastic blade 4 is 10 ⁶ V / cm <Emax <10 ⁸ V / cm, and under the conditions of this embodiment, The maximum voltage Vmax applied between the electrode 4a and the developing sleeve 3 is sufficiently within the above appropriate range.

In the present invention, since the oscillating voltage applied to the elastic blade 4 is controlled to a constant voltage, when the maximum voltage applied between the electrode 4a and the developing sleeve 3 is large, the toner layer surface layer on the developing sleeve 3 is not covered. The applied charge is increased, and when the maximum voltage applied between the electrode 4a and the developing sleeve 3 is small, the charge applied to the surface layer of the toner layer on the developing sleeve 3 is suppressed.

Therefore, from the elastic blade 4 to the developing sleeve 3
The electric charge given to the toner on the surface layer of the upper toner layer is suppressed in the low humidity environment and increased in the high humidity environment. Therefore, the toner can be charged to an appropriate charge amount without causing excessive toner charging in a low humidity environment and insufficient charging in a high humidity environment.

That is, according to this embodiment, it is possible to apply an appropriate charge to the toner regardless of the difference in environment, and as a result, it is possible to obtain a good image in which the image density does not decrease even when used for a long time. It has become possible.

The material of the elastic blade body 4b is not limited to hydrin rubber as long as it has appropriate environmental variability of resistance value. For example, urethane, NBR, or EPDM in which carbon or the like is dispersed to adjust the resistance can be used.

The polarity of the DC component of the bias applied to the electrode 4a may be either positive or negative. The AC component may have any waveform such as a sine wave, a rectangular wave, and a triangular wave, and a pulse wave may also be used. In short, any waveform having a vibration component may be used.

The position of the electrode 4a is determined by the elastic blade body 4
It suffices that the elastic blade main body 4b is inserted between the developing sleeve 3 and the electrode 4a, such as being provided not only in the inside of b but on the back surface of the elastic blade 4.

Embodiment 3 FIG. 7 is a schematic diagram showing still another embodiment of the developing device of the present invention. In this embodiment, the developing device 5A is integrated with the photosensitive drum 1, the primary charging roller 2, the cleaning blade 7, etc., and is detachably installed as a process cartridge 20 in the image forming apparatus main body. In FIG. 7, reference numeral 8
Is a waste toner box for collecting the toner collected by cleaning the surface of the photosensitive drum 1 with the cleaning blade 7, and the waste toner box 8 is also the process cartridge 20.
Be integrated into.

The construction of the developing device 5A itself is the same as that of the first embodiment, and the same reference numerals as those shown in FIG. 2 in FIG. 7 indicate the same members.

Also in this embodiment, the elastic blade body 4
For b, use a material whose resistance value changes depending on the humidity of the environment,
A blade bias having a vibration component may be applied to the elastic blade 4 while controlling the constant voltage.

Therefore, it becomes possible to provide the process cartridge 20 having a small size and a simple structure as a process cartridge which is not affected by long-term use or use environment.

In the process cartridge 20 described above, the developing device 5A is integrated with the photosensitive drum 1, the primary charging roller 2, the cleaning blade 7 and the like, but the invention is not limited to this, and at least the developing device is provided to form an image. It suffices if it can be attached to and detached from the apparatus body.

[0056]

As described above, according to the present invention, an electrode is provided on the developer regulating member which is in contact with the developer carrying member, and an oscillating voltage is applied between the electrode and the developer carrying member so as to develop these members. When the developer layer of the magnetic one-component developer on the agent carrier and the regulating member is peeled off and reciprocated to prevent uneven charging of the developer, uneven coating of the developer, and opposite polarity charging, the width of the electrode is set to 0. Since it is set to 3 mm or more and 2 mm or less, the capacitance between the electrode and the developer carrier is reduced while suppressing the manufacturing cost.
By reducing the amount of current flowing between the electrode and the developer carrier,
It becomes possible to use a smaller power source, and power consumption and power source cost can be kept low.

Further, a material whose volume resistivity changes with the humidity of the environment is used for the developer regulating member, and the above-mentioned oscillating voltage is applied to this regulating member while controlling the constant voltage.
By eliminating the uneven charging of the developer, uneven coating, and opposite polarity charging, the developer can be favorably charged, and a high-quality image having sufficient density without unevenness or fog can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is an enlarged view showing a main part of a developing device included in the image forming apparatus of FIG.

FIG. 3 is a plan view showing an elastic blade provided in the developing device of FIG.

FIG. 4 is a schematic configuration diagram showing another embodiment of the developing device according to the present invention.

5 is a graph showing changes in resistance value of hydrin rubber used for the elastic blade provided in the developing device of FIG. 4 depending on the environment.

6 is an explanatory diagram showing an electrically equivalent circuit of an interface between the elastic blade of the developing device of FIG. 4 and the developing sleeve.

FIG. 7 is a schematic configuration diagram showing a process cartridge including a developing device according to still another embodiment of the present invention.

FIG. 8 is a schematic configuration diagram showing a conventional image forming apparatus.

9 is an explanatory diagram showing a state of toner in the vicinity of a sliding portion of an elastic blade and a developing sleeve of a developing device included in the image forming apparatus of FIG.

FIG. 10 is a schematic configuration diagram showing an image forming apparatus including another conventional developing device.

11 is an explanatory diagram showing a force acting on the toner when an electric field due to a blade bias is directed from the elastic blade toward the developing sleeve in a sliding portion between the elastic blade and the developing sleeve of the developing device in FIG.

FIG. 12 is an explanatory diagram showing a force acting on the toner when an electric field due to the blade bias is directed from the developing sleeve toward the elastic blade.

FIG. 13 is an explanatory view showing how the toner reciprocates on the downstream side of the rubbing portion.

[Explanation of symbols]

 1 Photosensitive Drum 3 Developing Sleeve 4 Elastic Blade 4a Electrode 4b Blade Body 4c High Resistance Layer 5A Developing Device 6 Magnetic Toner 12 Magnets 15 and 16 Bias Power Supply

(72) Inventor Junichi Kato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Koichi Suwa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masashi Ojima 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroshi Sato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. ( 72) Inventor Satoshi Inami 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tetsuya Sano 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Invention Mr. Seiji Yamaguchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (6)

[Claims] 1. A magnetic one-component developer carried on a developer carrying member and conveyed to a developing section facing the latent image carrying member is brought into contact with the developer carrying member to regulate the magnetic one-component developer. In a developer regulating member made of an elastic body for applying a developer layer having a predetermined layer thickness on a developer carrier, the developer regulating member has an electrode facing the developer carrier, and the width of the electrode is 0. A developer regulating member having a size of 3 mm or more and 2 mm or less. 2. The developer regulating member according to claim 1, wherein the elastic body of the developer regulating member has a volume resistivity that varies depending on the humidity of the environment. 3. A developing device comprising the developer regulating member according to claim 1 or 2. 4. An image forming apparatus comprising the developing device according to claim 3, wherein an oscillating electric field is applied between the developer regulating member and the developer carrying member. 5. The constant voltage control of the oscillating electric field.
Image forming device. 6. A process cartridge which includes at least a developing device and is detachable from an image forming device, wherein the developing device is the developing device according to claim 3.