JPH09197814A - Developing device, process cartridge and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device, a process cartridge and an image forming device capable of stably, excellently forming a toner thin layer on a developing sleeve by an elastic blade, and preventing toner from sticking to an electrode plate on the nip downstream side of a developing blade, especially, even in the case of using the spherical toner whose surface smoothness is high. SOLUTION: The rubber elastic layer 16 is formed thinner on the nip part downstream side of the developing blade 7 in the rotating direction of the developing sleeve 5 than on the nip part upstream side, or the elastic layer 16 is not provided on the nip part downstream side, whereby a gap between an electrode layer 17 and the sleeve 5 is widened. Thus, flying force and attracting force for the toner 8 on the sleeve 5 by alternating electric field generated between the layer 17 and the sleeve 5 are mitigated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine or an electrophotographic printer, a developing apparatus used for the image forming apparatus, and a process cartridge.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus, an electrostatic latent image formed on an image bearing member is visualized as a toner image by a developing device. As such, various dry one-component developing devices have been proposed and put into practical use. However, it is difficult for any developing device to form a thin layer of toner, which is a one-component developer, on a developer carrier.

At the present time, however, it is required to improve the resolution and sharpness of an image, and development of a toner thin layer forming method and its apparatus is indispensable, and some measures are proposed for this. Has been done.

For example, as disclosed in Japanese Patent Laid-Open No. 54-43038, an elastic regulating blade made of rubber or metal is brought into contact with a developing sleeve as a developer carrying member, and the elastic regulating blade is brought into contact with the developing sleeve. By allowing the toner to pass through between the contact portions and regulating the toner, a thin layer of the toner is formed on the developing sleeve, and sufficient tribo is imparted to the toner by friction at the contact.

In this case, when the non-magnetic toner is regulated by the elastic regulation blade, a toner supply member for supplying the toner onto the developing sleeve is required separately. In the case of a magnetic toner, since the toner can be held on the developing sleeve by the magnetic force of the magnet in the developing sleeve, a toner supply member is not required, but in the case of a non-magnetic toner, the toner due to the magnetic force is used. This is because it cannot be held.

In order to solve this problem, Japanese Patent Laid-Open No. 58-1
As disclosed in Japanese Patent No. 16149, the developing device shown in FIG. 7 has been proposed. In the conventional developing device of this proposal, in the developing container 14 containing the non-magnetic toner 8 as a one-component developer, the developing sleeve 5 is located upstream of the contact portion between the elastic regulating blade 22 and the developing sleeve 5 in the rotational direction of the developing sleeve 5. An elastic roller 6 having a fur brush structure that comes into contact with the developing sleeve 5 at a position is installed so that the toner 8 remaining on the developing sleeve 5 that is not consumed for development is peeled off by the elastic roller 6 and a new toner is formed on the developing sleeve 5. The toner 8 is supplied.

With the above arrangement, a thin layer of the non-magnetic toner 8 can be satisfactorily formed on the developing sleeve 5, and the electrostatic latent image on the image carrier can be satisfactorily developed. It was

Regarding the contact direction of the elastic regulating blade, it is known that the reverse contact as shown in FIG. 7 is more preferable than the normal contact in the rotation direction of the developing sleeve. That is, in the case of normal contact, the number of developing operations increases and toner agglomerates between the developing sleeve and the elastic regulating blade, and the aggregated toner particles push up the elastic regulating blade with the rotation of the developing sleeve, so that a uniform thin film is formed. This is because the layer toner coat cannot be maintained and the particles are conveyed on the developing sleeve in an agglomerated state, which appears as an image defect. In order to eliminate this decrease, it is conceivable to increase the contact pressure of the elastic regulation blade with respect to the developing sleeve, but in that case, the elastic regulation blade and the toner are significantly damaged, and the elastic blade is fused with the toner. As for the toner, toner deterioration occurs.

On the other hand, in the case of reverse contact, the contact pressure of the elastic regulating blade is not increased and the elastic regulating blade is not pushed up by the agglomerated toner, so that a stable thin layer toner coat is always provided. It can be maintained.

Further, in order to stably maintain a thin layer of non-magnetic toner for a long period of time, as disclosed in JP-A-60-103371 and JP-A-62-27314, elasticity regulation is required. It is known to generate an alternating electric field in a space between a blade and a developing sleeve which is a developer carrying member.

[0011]

However, when the developing operation is repeated a large number of times with the above-mentioned configuration of the prior art, it is also used as a pressing member for the elastic regulating blade, which is located downstream of the nip between the developing sleeve and the elastic regulating blade. Due to the alternating electric field formed between the electrode plate as a conductive layer and the developing sleeve, a part of the toner on the developing sleeve regulated to a thin layer adheres to the electrode plate of the elastic regulation blade, and the toner deposited in due time. Since the toner is pulled back onto the developing sleeve, an image defect may occur in which the toner directly appears on the image.

Further, this phenomenon is excellent in transferability when transferring from an image carrier to a transfer material by a transfer means (not shown), and transfer residual toner remaining on the image carrier without being transferred is transferred to a blade or a fur. It is remarkably seen by using a toner having advantages such as less abrasion of the image bearing member due to high lubricity when cleaning by a cleaning means such as a brush, that is, a spherical toner having a smooth surface, Since the toner has high lubricity and is easily aggregated, the toner easily passes through the elasticity regulating blade, and the toner that has passed may adhere to the electrode plate of the elasticity regulating blade.

Therefore, the present invention stably and favorably forms a thin toner layer on the developing sleeve by the elastic regulating blade, and particularly when a spherical toner having a high surface smoothness is used, the nip of the elastic regulating blade is increased. An object of the present invention is to provide a developing device, a process cartridge, and an image forming apparatus in which toner does not adhere to the electrode plate on the downstream side.

[0014]

According to a first invention of the present application, the above object is to provide a developing container for containing a developer,
A rotating developer carrier extending into the opening of the developing container; an elastic regulating blade that is in contact with the developer carrier via the developer; and a developer carrier of the elastic regulating blade. A rotatable elastic roller provided in contact with the contact portion on the upstream side in the rotation direction of the developer carrier, wherein the elastic regulating blade is long at least at the contact portion with the developer carrier. In a developing device having a conductive layer across a rubber elastic layer in a direction, and forming an alternating electric field between the conductive layer and the developer carrying member, the rubber elastic layer of the elastic regulating blade includes the elastic regulating blade and the developing layer. This is achieved by forming the developer carrier at a position downstream of the contact part of the developer carrier in the rotational direction of the developer carrier so as to be thinner than the thickness of the contact part and having a predetermined gap with the developer carrier. It

According to the second invention of the present application,
The above-mentioned object is a developing container for accommodating a developer, a rotating developer carrying member extending to the opening of the developing container, and an elastic regulating blade that is in contact with the developer carrying member via the developer. A rotatable elastic roller provided in contact with an abutting portion of the elastic restriction blade with the developer carrying member, the rotatable elastic roller being provided in contact with an upstream side in the rotation direction of the developer carrying member. In the developing device, which comprises a conductive layer at least in a contact portion with the developer carrying member in the longitudinal direction via a rubber elastic layer, and forms an alternating electric field between the conductive layer and the developer carrying member, the elastic regulating blade. The rubber elastic layer is not provided on the downstream side in the rotation direction of the developer carrying member with respect to the contact portion between the elastic restriction blade and the developer carrying member, and the conductive layer is the developer carrying member. And reach by having a certain gap It is.

Further, according to the third invention of the present application, the object is according to the second invention, and the shape of the conductive layer in the portion of the elastic elasticity regulating blade where the rubber elastic layer is not provided is This is achieved by having an inclination in the direction away from the developer carrying member rather than the portion having the rubber elastic layer.

According to the fourth aspect of the present invention,
The above object is any one of the first to third inventions, wherein the developer is a non-magnetic one-component developer, the shape factor SF-1 is 100 to 180, and the shape factor SF-2 is 100 to 180. This is achieved by being 140.

Further, according to the fifth invention of the present application, the above-mentioned object is at least the above-mentioned first to fourth inventions.
The present invention is achieved by incorporating the developing device according to any one of the inventions 1 to 3 into a process cartridge that is attachable to and detachable from the image forming apparatus.

According to a sixth aspect of the present invention,
The above object is achieved by providing an image forming apparatus including at least the process cartridge of the fifth invention.

That is, in the first aspect of the present invention, the rubber elastic layer of the elastic regulating blade is located downstream of the contact portion between the elastic regulating blade and the developer carrying member in the rotational direction of the developer carrying member. Since it is formed thinner than the thickness of the contact portion and has a predetermined gap with the developer carrier, the alternating electric field strength generated on the downstream side of the contact portion between the elastic regulation blade and the developer carrier is reduced. The developer flying caused by the alternating electric field in the space is suppressed, and the developer adhesion to the conductive layer of the elastic regulation blade is reduced.

Further, in the second invention according to the present application, the rubber elastic layer of the elastic regulating blade is located on the downstream side of the contact portion between the elastic regulating blade and the developer carrying member in the rotational direction of the developer carrying member. Since it is not provided and has a predetermined gap with the developer carrying member, the alternating electric field strength generated at the downstream side of the contact portion between the elastic restriction blade and the developer carrying member is reduced, and the alternating electric field in that space is reduced. The developer flying caused by the electric field is suppressed, and the developer adhesion to the conductive layer of the elasticity regulating blade is reduced.

Further, in the third invention according to the present application, the conductive layer of the elastic elasticity regulating blade of the second invention, which is not provided with the rubber elastic layer, is more developed than the portion having the rubber elastic layer. Since the shape is inclined in the direction away from the carrier, the alternating electric field strength generated on the downstream side of the contact portion between the elastic regulation blade and the developer carrier is reduced as compared with the second invention, and the space in that space is reduced. It suppresses the developer flying due to the alternating electric field and reduces the developer adhesion to the conductive layer of the elasticity regulating blade.

According to a fourth invention of the present application, in any one of the first to third inventions, the developer is a non-magnetic one-component developer and has a shape factor S.
F-1 is 100 to 180, and shape factor SF-2 is 100 to 180.
Since it is 140, development with a developer having excellent transferability and less wear of the image carrier during cleaning is executed while reducing the adhesion of the developer to the conductive layer of the elastic regulation blade.

Further, in a fifth invention according to the present application, there is provided a process cartridge which is conjoined with at least the developing device according to any one of the first to fourth inventions and which is attachable to and detachable from the image forming apparatus. By doing so, it is possible to reduce the adhesion of the developer to the conductive layer of the elastic regulation blade, perform good development, and improve maintainability.

Further, in the sixth invention according to the present application, the image forming apparatus is provided with at least the process cartridge of the fifth invention, so that the adhesion of the developer to the conductive layer of the elasticity regulating blade is reduced. Good image formation is performed, and maintainability is improved.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS. FIG.
2 and FIG. 2 are cross-sectional views of the image forming apparatus and the developing device of this embodiment. In FIG. 1, a photosensitive drum 1 as an image carrier rotates in the direction of arrow A and is uniformly charged by a charging device 2 for charging the photosensitive drum 1 to write an electrostatic latent image on the photosensitive drum 1. An electrostatic latent image is formed on the surface by the laser light 3 which is the exposing means.

This electrostatic latent image is developed by a developing device 4 which is disposed close to the photosensitive drum 1 and which is detachable from the image forming apparatus as a process cartridge and visualized as a toner image. In the present embodiment, so-called reversal development is performed to form a toner image on the exposed portion.

The visualized toner image on the photosensitive drum 1 is transferred onto the paper 13 which is a recording medium by the transfer roller 9, and the transfer residual toner remaining on the photosensitive drum 1 without being transferred is scraped off by the cleaning blade 10. The photosensitive drum 1 which has been stored in the waste toner container 11 and cleaned has the above-described operation repeated to form an image.

On the other hand, the paper 13 on which the toner image has been transferred is fixed by the fixing device 12 and discharged outside the device to complete the printing operation.

Next, the developing device 4 in the apparatus of this embodiment as described above will be described in more detail with reference to FIG.

In FIG. 2, reference numeral 14 denotes a developing container containing a non-magnetic toner 8 as a one-component developer, which is the main developing device 4
Is provided with a developing sleeve 5 as a developer carrying member, which is located at an opening extending in the longitudinal direction in the developing container 14 and is opposed to the photosensitive drum 1, and develops an electrostatic latent image on the photosensitive drum 1. To visualize it.

In the developing device 4, the developing sleeve 5 has a substantially semi-peripheral surface on the right side shown in the drawing at the opening portion.
4 is provided laterally with the left substantially half peripheral surface exposed to the outside of the developing container 14. The surface exposed to the outside of the developing container 14 is
The photosensitive drum 1 located on the left side of the developing container 14 is opposed to the photosensitive drum 1 with a slight interval. The developing sleeve 5 is rotationally driven in the direction of arrow B, and the surface thereof has appropriate irregularities for increasing the probability of rubbing with the toner 8 and favorably carrying the toner 8.

An elastic regulating blade 7 is provided at an upper position thereof so that it is supported by the pressing plate 15 and the vicinity of the tip on the free end side is brought into surface contact with the outer peripheral surface of the developing sleeve 5. The contact direction is a so-called counter (reverse) direction in which the front end side is located upstream in the rotation direction of the developing sleeve 5 with respect to the contact portion.

The elastic regulating blade 7 has a conductive layer 17 via a rubber elastic layer 16 at least at a portion in contact with the developing sleeve 5. In this embodiment, the rubber elastic layer 16 has a repulsive elasticity. 20% or more of urethane rubber, silicone rubber or the like is used, and a thin metal plate of stainless steel or phosphor bronze having spring elasticity is provided as the conductive layer 17. In other words, this thin metal plate maintains the pressure contact force of the elastic regulating blade 7 with respect to the developing sleeve 5, and also serves as an electrode when an alternating electric field is formed between the thin metal plate and the developing sleeve 5 in the present invention.

A power source 18 capable of applying AC (alternating) and DC voltages is connected to the metal thin plate as the electrode, and is controlled so as to form a predetermined alternating electric field with the developing sleeve 5. .

The developing sleeve 5 and the elastic regulating blade 7
The method of applying the alternating electric field formed in between and the effect thereof will be described in detail later.

The elastic roller 6 is rotatably supported in contact with the contact portion of the elastic regulating blade 7 with the surface of the developing sleeve 5 on the upstream side in the rotating direction of the developing sleeve.

In the main developing device 4 as described above, the toner 8 in the developing container 14 is stirred by the stirring member 19 during the developing operation.
The toner is sent in the direction of the elastic roller 6 as the arrow C rotates. Further, the toner 8 is carried to the vicinity of the developing sleeve 5 by the elastic roller 6 rotating in the direction of the arrow D, and the toner 8 carried on the elastic roller 6 at the contact portion between the developing sleeve 5 and the elastic roller 6. Is frictionally charged by being rubbed against the developing sleeve 5, and adheres to the developing sleeve 5.

Then, with the rotation of the developing sleeve 5 in the direction of arrow B, an AC voltage (blade AC bias) superposed with DC by the power source 18 is sent under pressure contact with the elastic regulating blade 7, where appropriate. After being subjected to tribo (amount of triboelectric charge), a thin layer is formed on the developing sleeve 5, and then the developing sleeve 5 is conveyed to a developing portion which is a portion facing the photosensitive drum 1.

The undeveloped toner that has not been consumed in the developing section is rotated by the developing sleeve 5 and the developing sleeve 5 is rotated.
Collected from the bottom of A seal member 2 is provided in this recovery portion.
0 is provided to allow passage of undeveloped toner into the developing container 14 and prevent the toner 8 in the developing container 14 from leaking from the lower portion of the developing sleeve 5.

The collected undeveloped toner on the developing sleeve 5 is peeled off from the surface of the developing sleeve 5 at the contact portion between the elastic roller 6 and the developing sleeve 5. Most of the peeled toner is transported as the elastic roller 6 is rotated and mixed with the toner 8 in the developing container 14, and the charged electric charge of the toner is dispersed. At the same time, new toner is supplied onto the developing sleeve 5 by the rotation of the elastic roller 6, and the above-described operation is repeated.

In the developing section, the latent image on the photosensitive drum 1 has a power source 21 between the developing sleeve 5 and the photosensitive drum 1.
AC voltage (development AC
A toner image is developed by the electric field generated by the bias.

Next, specific examples of each component in the developing device 4 in this embodiment will be described below.

The developing sleeve 5 has a surface roughness Rz (JIS10) obtained by subjecting an aluminum sleeve surface having a diameter of 16 mm to a standard blast treatment with glass beads (# 600).
The point average roughness (according to JIS B0601) is set to about 3 μm, and it is opposed to the photosensitive drum 1 so that the gap between the photosensitive drum 1 and the photosensitive drum 1 is 300 μm. It was rotated at / s.

Toner 8 is a non-magnetic one-component developer,
As described above, the transferability is excellent, and when the transfer residual toner that has not been transferred and remains on the photosensitive drum 1 is cleaned by a cleaning unit such as a blade or a fur brush, the lubricating property is high, so that the photosensitive drum 1 is less worn. A toner having advantages such as, for example, a toner having a spherical shape and a smooth surface is used. Specifically, as a shape factor, SF-1 is 100 to 180, and SF-2
Is 100 to 140. This SF-
1 and SF-2 are Hitachi FE-SEM (S-80
0) was used to randomly sample 100 toner images, and the image information was introduced into an image analysis device (Luxex3) manufactured by Nikole Co. through an interface for analysis, and the value calculated by the following formula was defined. ing.

SF-1 = (MXLNG)^Two/ AREA ×
π / 4 × 100 SF-2 = (PERI) / AREA × π / 4 × 100 (AREA: toner projected area, MXLNG: absolute maximum
Length, PERI: Perimeter)

The shape factor SF-1 of this toner shows the degree of sphere, and as it increases from 100, it gradually changes from a spherical shape to an irregular shape. SF-2 indicates the degree of unevenness, and as the value increases from 100, the unevenness of the toner surface becomes more remarkable.

As a method for producing a toner, in addition to the production method by a so-called crushing method within the range of the above shape factor, JP-A-36-10231 and JP-A-59-78 are available.
No. 56, a method of directly producing a toner by using the suspension polymerization method, or a dispersion polymerization of directly producing a toner by using an aqueous organic solvent in which a monomer is soluble and the obtained polymer is insoluble. The toner can be produced by a method or an emulsion polymerization method typified by a soap-free polymerization method in which a toner is directly polymerized in the presence of a water-soluble polar polymerization initiator.

In this embodiment, the toner shape factor S
F-1 to 100-180, SF-2 to 100-140
The suspension polymerization method under normal pressure or under pressure can be used to obtain a fine particle toner having a sharp particle size distribution and a particle size distribution of 4 to 8 μm. Acrylate, salicylic acid metal compound as a charge control agent, saturated polyester as a polar resin, and a colorant are added, and a weight average particle diameter of 7 μm
m colored suspended particles were produced.

Then, 1.5 wt% of hydrophobic silica is added to this.
% By external addition, a toner 8 having a negative polarity, which is excellent in transferability as described above and has less wear during cleaning of the photosensitive drum 1, was manufactured.

The elastic roller 6 has a foam skeletal sponge structure or a fur brush structure in which fibers such as rayon and nylon are planted on a core metal, and the toner 8 is supplied to the developing sleeve 5 and the undeveloped toner is peeled off. This is preferable, and in the present embodiment, the elastic roller 6 having a diameter of 12 mm in which pre-urethane foam is provided on the cored bar is used. The contact width of the elastic roller 6 with the developing sleeve 5 is 1
-8 mm is effective, and it is preferable that the abutting portion has a relative speed with respect to the developing sleeve 5. In the present embodiment, the abutting width is set to 3 mm, and the developing speed is set as the peripheral speed of the elastic roller 6. At some times, it was rotationally driven at a predetermined timing by a driving means (not shown) so as to be 50 mm / s (the relative speed to the developing sleeve 5 was 130 mm / s).

Next, the developing sleeve 5 and the elastic regulating blade 7
The method of applying the alternating electric field formed between and the effect will be described in detail.

As described above, the developing sleeve 5 and the elastic regulating blade 7 are connected to the power sources 21 and 18 capable of applying the AC (alternating) voltage and the DC voltage, respectively, and serve as the developing bias during the developing operation. From No. 21, a peak-to-peak voltage of 2000 V and a frequency of 2000 Hz are applied in a rectangular wave as an AC (alternating) component to the developing sleeve 5.
-400V is applied as a DC component. As a result, so-called reversal development is performed in which the toner 8 having a negative polarity is developed with respect to the latent image potential portion of -150 V in the exposed portion of the photosensitive drum 1 (the potential of the non-exposed portion is -600 V).

The blade bias applied to the electrode layer 17 of the elasticity regulating blade 7 is a DC component of -400 V, which is the same as the developing bias, and an AC (alternating) component is a rectangular wave having the same phase as the developing bias and a peak-to-peak voltage of 1400.
V and a frequency of 2000 Hz are applied.

Here, the rubber elastic layer 16 is the developing sleeve 5
In terms of preventing leakage between the conductive layer 17 and the conductive layer 17, it is of course possible to have a resistance of a predetermined value or more, and the volume resistance is 10 ¹⁰ Ω · c.
m or more.

However, even when the elasticity regulating blade as described above is used, the toner 8 on the developing sleeve 5 may adhere to the downstream side of the nip portion of the elasticity regulating blade 7 by repeating the image forming operation.

Therefore, in the present invention, as shown in FIG. 3 or 4, for example, the rubber elastic layer 16 on the downstream side of the nip portion with respect to the rotating direction of the developing sleeve 5 of the developing blade 7 is compared to the upstream side of the nip portion. The thickness of the developing sleeve 5 is made thin or the rubber elastic layer 16 is not provided on the downstream side of the nip portion to widen the gap between the electrode layer 17 and the developing sleeve 5, thereby developing the developing sleeve of the alternating electric field generated therebetween. The flying force and suction force on the toner 8 on the toner 5 are alleviated.

Table 1 shows the results of a comparative examination of the effects of the elastic restriction blades shown in FIGS. 3 and 4 of the present embodiment with respect to the conventional elastic restriction blade.

As an evaluation method, a character pattern (the pattern is not particularly limited) having an image ratio of about 4% with respect to the printable area is formed, and a developing sleeve is formed after forming a predetermined number of images. 5 and the state of adhesion of the toner on the downstream side of the nip portion of the elasticity regulating blade 7 were observed, and it was judged by the presence or absence of an image defect due to the adhered toner on the formed image.

[0061]

[Table 1]

As can be seen from the results in Table 1, toner adhesion was recognized in the conventional elastic regulation blade from the early stage of image formation, and after several tens of sheets of image formation, the adhered toner was gradually separated from the elastic regulation blade to cause image defects. Is appearing.

On the other hand, the elastic regulating blade 7 of the type in which the rubber elastic layer on the downstream side of the nip portion is gradually thinned
In the case of image formation up to 1000 sheets, toner adhesion to the downstream side of the nip portion was slight, and an image defect due to the toner adhesion did not occur.

Further, in the case of the type in which the rubber elastic layer was not provided on the downstream side of the nip portion, toner adhesion was not recognized even in repeated image formation, and of course no image defect due to it was generated.

Further, the electric field strength E (V / m) between the developing sleeve 5 and the elasticity regulating blade 7 is about 2 × 10 ⁵ (V / m) depending on the bias applied to the elasticity regulating blade 7 in the conventional example. m) to 9 × 10 ⁵ (V / m), but the effect of the present invention can be sufficiently obtained by adopting the optimum configuration shown in this embodiment for the electric field strength in these ranges. Can be demonstrated.

As described above, by using the elasticity regulating blade having the structure according to the present invention, the elasticity regulating blade is developed in the developing device using the non-magnetic one-component developer or at least the image forming apparatus using the same. Even if a bias with a different amplitude from that of the developing sleeve is applied to the elastic regulating blade while being in contact with the sleeve in the counter direction, the elastic regulating blade is downstream of the nip portion with the developing sleeve without damaging the toner coating. It is possible to avoid the toner adhesion to the side, and the defect caused by it is not generated.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, the shape of the electrode plate as a conductive layer which doubles as the contact member for the elastic regulating blade to the developing sleeve is different from that of the first embodiment. The electrode plate is bent in the direction opposite to the side where the developing sleeve is located at the boundary of the plate.

In other words, in the present embodiment, the electrode plate of the elastic regulating blade is formed so as to be as far away from the developing sleeve as possible, so that the influence of the alternating electric field generated between the elastic regulating blade and the developing sleeve is small even when developing. It is characterized in that the toner on the sleeve is not affected.

By applying the configuration of this embodiment, the first
The same effect as the embodiment of

Although there is a slight difference in shape between FIG. 4 and FIG. 5 in this embodiment, there is no restriction on the shape as long as it can make contact with the developing sleeve with a predetermined pressure contact force. Any shape may be adopted as long as it is within the range specified in this embodiment.

Further, by adopting the shape of this embodiment, unlike the conventional example, the degree of freedom in designing the cartridge structure having the developing device is increased, and the size can be further reduced.

Further, in the first and second embodiments, the process cartridge is composed of the developing device which can be attached to and detached from the main body of the image forming apparatus, but it is fixed in the main body of the image forming apparatus and only the toner is replenished. The developing device, the photosensitive drum, the cleaning blade, the waste toner container, and the charging device may be integrally formed to be used as a process cartridge that can be attached to and detached from the main body of the image forming apparatus.

[0074]

As described above, the first embodiment according to the present application is described.
In the invention, the rubber elastic layer of the elastic regulation blade is formed to be thinner than the thickness of the contact portion on the downstream side in the rotation direction of the developer carrier relative to the contact portion of the elastic regulation blade and the developer carrier. Since there is a predetermined gap with the agent carrier, the strength of the alternating electric field generated on the downstream side of the contact portion between the elastic regulation blade and the developer carrier is reduced, and the developer flying due to the alternating electric field in the space is reduced. Can be suppressed and the adhesion of the developer to the conductive layer of the elastic regulation blade can be reduced. As a result, a stable developer coating can always be realized without causing the image disturbance caused by the excessive adhesion of the developer to the elastic regulation blade.

Further, in the second invention according to the present application, the rubber elastic layer of the elastic regulating blade is located on the downstream side of the contact portion between the elastic regulating blade and the developer carrying body in the rotation direction of the developer carrying body. Since it is not provided and has a predetermined gap with the developer carrying member, the alternating electric field strength generated at the downstream side of the contact portion between the elastic restriction blade and the developer carrying member is reduced, and the alternating electric field in that space is reduced. It is possible to suppress the developer flying due to the electric field and reduce the developer adhesion to the conductive layer of the elasticity regulating blade. As a result, a stable developer coating can always be realized without causing the image disturbance caused by the excessive adhesion of the developer to the elastic regulation blade.

Further, in the third invention according to the present application, the conductive layer of the elastic elasticity regulating blade of the second invention, which is not provided with the rubber elastic layer, is more developed than the portion having the rubber elastic layer. Since the shape is inclined in the direction away from the carrier, the alternating electric field strength generated on the downstream side of the contact portion between the elastic regulation blade and the developer carrier is reduced as compared with the second invention, and the space in that space is reduced. It is possible to suppress the flying of the developer due to the alternating electric field and reduce the adhesion of the developer to the conductive layer of the elasticity regulating blade. As a result, a stable developer coating can always be realized without causing the image disturbance caused by the excessive adhesion of the developer to the elastic regulation blade.

According to a fourth invention of the present application, in any one of the first to third inventions, the developer is a non-magnetic one-component developer, and the shape factor S
F-1 is 100 to 180, and shape factor SF-2 is 100 to 180.
Since it is 140, it is possible to perform development with a developer that is excellent in transferability and that causes less wear of the image bearing member during cleaning, while reducing developer adhesion to the conductive layer of the elastic regulation blade.

Further, in the fifth invention according to the present application, there is provided a process cartridge which comprises at least the developing device according to any one of the first to fourth inventions and which is attachable to and detachable from the image forming apparatus. By doing so, it is possible to reduce the adhesion of the developer to the conductive layer of the elastic regulation blade, perform good development, and improve the maintainability.

Further, in the sixth invention of the present application, the image forming apparatus is provided with at least the process cartridge of the fifth invention to reduce the adhesion of the developer to the conductive layer of the elasticity regulating blade. Thus, good and stable image formation can be performed, and maintainability can be improved.

[Brief description of drawings]

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

FIG. 2 is a schematic cross-sectional view of the developing device according to the first embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of the elasticity regulating blade of the first embodiment according to the present invention.

FIG. 4 is a schematic cross-sectional view of the elasticity regulating blade of the first embodiment according to the present invention.

FIG. 5 is a schematic sectional view of an elasticity regulating blade of a second embodiment according to the present invention.

FIG. 6 is a schematic sectional view of an elasticity regulating blade of a second embodiment according to the present invention.

FIG. 7 is a schematic cross-sectional view of a conventional non-magnetic one-component developing device.

[Explanation of symbols]

 4 Developing Device 5 Developing Sleeve (Developer Carrier) 6 Elastic Roller 7 Elasticity Regulation Blade 8 Toner (Developer) 14 Developing Container 16 Rubber Elastic Layer 17 Conductive Layer

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masahide Kinoshita 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (6)

[Claims] 1. A developer container containing a developer, a rotating developer carrier extending into an opening of the developer container, and an elastic regulating blade abutting against the developer carrier via the developer. And a rotatable elastic roller provided in contact with an abutment portion of the elastic restriction blade with the developer carrying member on the upstream side in the rotation direction of the developer carrying member. In a developing device in which a conductive layer is provided through a rubber elastic layer at least in a contact portion with the developer carrying member through a rubber elastic layer, and an alternating electric field is formed between the conductive layer and the developer carrying member, the elastic regulation The rubber elastic layer of the blade is formed to be thinner than the thickness at the contact portion on the downstream side in the rotation direction of the developer bearing member from the contact portion between the elastic regulation blade and the developer bearing member. Must have a certain clearance from the body Developing device. 2. A developer container containing a developer, a rotating developer carrier extending into an opening of the developer container, and an elastic regulating blade abutting against the developer carrier via the developer. And a rotatable elastic roller provided in contact with an abutment portion of the elastic restriction blade with the developer carrying member on the upstream side in the rotation direction of the developer carrying member. In a developing device in which a conductive layer is provided through a rubber elastic layer at least in a contact portion with the developer carrying member through a rubber elastic layer, and an alternating electric field is formed between the conductive layer and the developer carrying member, the elastic regulation The rubber elastic layer of the blade is not provided on the downstream side in the rotation direction of the developer carrying member with respect to the contact portion between the elasticity regulating blade and the developer carrying member, and the conductive layer is the developer carrying member. Characterized by having a predetermined gap with the body Developing device. 3. The shape of the conductive layer in a portion of the elastic-elasticity regulating blade where the rubber elastic layer is not provided is inclined in a direction away from the developer carrying member as compared with the portion having the rubber elastic layer. The developing device according to claim 2. 4. The developer according to claim 1, wherein the developer is a non-magnetic one-component developer, the shape factor SF-1 is 100 to 180, and the shape factor SF-2 is 100 to 140. The developing device as described in 1 above. 5. A process cartridge, comprising at least the developing device according to any one of claims 1 to 4, which is attached to and detachable from an image forming apparatus. 6. An image forming apparatus comprising at least the process cartridge according to claim 5.