JPH05158337A - Developing device - Google Patents

Abstract

(57) [Summary] [Objective] The toner layer regulation member has a uniform and stable pressure contact force with respect to the toner image carrier so that the toner layer has a uniform layer thickness in the same width direction. The toner can be stably formed, and the toner scattering from the end portion of the toner layer regulating member in the same width direction can be effectively prevented. [Structure] Doctor plate 8 which is a toner layer regulating member
Is a flexible plate made of metal or the like, and the central portion in the rotation direction of the developing roller 5 is projected to the surface side of the developing roller 2 and the curvature of the width direction end portion is the central portion in the same direction. In the state of being bent so as to become larger than the curvature of the fixing roller 9a, 9b, the two end edges in the same direction are pressed against the surface of the developing roller 2.
Is fixed to a fixed position of the casing of the developing device 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as a copying machine, a facsimile machine, a printer, or the like, and more specifically, to a layer thickness of toner on the surface of a toner carrier which is rotationally driven. In a developing device for visualizing a latent image formed on a latent image bearing member by toner carried on a toner bearing member in a developing area after being regulated to a predetermined thickness by a toner layer regulating member that is pressed against the surface, The present invention relates to stable formation of the toner layer.

[0002]

2. Description of the Related Art Conventionally, as a toner layer regulating member in a developing device of this type, as shown in FIG. Part of which is constituted by a regulation roller 90 which is rotationally driven so that the surfaces thereof move in the same direction (for example, see JP-A-59-125567),
As shown in FIG. 11 (b), one composed of a flexible thinning blade member 90 having one end fixed to the developing roller 5 so that the free end is in pressure contact (for example, Japanese Patent Laid-Open No.
No. -43038) is known.

[0003]

However, in the former toner layer regulating member, the pressure contact force of the regulating roller 90 against the developing roller 5 is uniform in the axial direction due to the presence of axial deflection due to the weight of the regulating roller 90. Since it is difficult to adjust the thickness, and the pressure contact force becomes non-uniform in the axial direction, there is a problem that the toner layer thickness after regulation becomes non-uniform in the axial direction, resulting in uneven density of a developed image. Further, in the latter toner layer regulating member, since it is a plate-shaped member, unevenness of the pressure contact force in the axial direction of the developing roller 5 due to its own weight unlike the above-mentioned regulation roller 90 does not occur, but it penetrates into the pressure contact portion. Due to the toner layer thickness on the developing roller 5 coming in, the pressure contact force with respect to the developing roller 5 is likely to change, which causes a problem that the toner layer thickness after regulation fluctuates, resulting in uneven density of a developed image. It was Further, since the widthwise both end edges of the free end are not restrained at all, the pressure contact force at the widthwise end tends to be smaller than that at the center in the same direction, and the toner from the end tends to be less. There was also a problem that scattering was likely to occur.

The present invention has been made in view of the above problems, and a first object of the present invention is to make a pressure contact force of a toner layer regulating member against a toner image bearing member a width perpendicular to a moving direction of the surface of the toner bearing member. It is an object of the present invention to provide a developing device capable of stably forming a toner layer having a uniform layer thickness in the same width direction with a uniform pressure contact force in the same direction.
A second object of the present invention is to provide a developing device that can effectively prevent toner scattering from the end portion of the toner layer regulating member in the same width direction.

[0005]

In order to achieve the above object, the present invention is to carry and carry toner on the surface of a toner carrier which is rotationally driven, and to press the layer thickness of the toner against the surface. After the toner image is regulated by the toner layer regulating member, the latent image formed on the latent image carrier is visualized by the toner carried on the toner carrier in the developing area where the latent image carrier and the toner carrier face each other. In a developing device for image formation, the toner layer regulating member is bent so that the central portion of the flexible plate-shaped member in the moving direction of the surface of the toner carrier projects toward the surface of the toner carrier. In this state, both end edges in the same direction are fixed at fixed positions. Here, the plate-shaped member is bent so that the curvature of the end portion in the width direction orthogonal to the moving direction of the surface of the toner carrier is larger than the curvature of the central portion in the same direction. It is desirable to fix it. Further, as the toner image carrier, there can be used one in which a large number of minute closed electric fields are formed in the vicinity of the surface and the charged electric field is attracted and carried by the closed electric fields.

[0006]

In the developing device of the present invention, the toner layer regulating member is bent so that the central portion of the flexible plate member in the moving direction of the surface of the toner carrier protrudes toward the surface of the toner carrier. Both edges in the same direction are fixed in a fixed state in a fixed state, and the central portion is pressed against the surface of the toner carrier to regulate the toner layer thickness. Since both edge portions of the plate member are fixed at fixed positions, a drag force from the toner carrying member side is applied as a load to the central portion of the both ends supporting beam. The maximum amount of deflection Ymax when a concentrated load is applied to the central portion of such a double-ended support beam is generated in this central portion and is expressed by the following equation (1). On the other hand, the conventional thinning blade 90 has a mechanism in which a reaction force from the toner carrier side is applied as a load to the free end portion. The maximum amount of deflection Yma when a concentrated load is applied to the free end of such a cantilever
x is generated at this free end and is expressed by the following equation (2). However, in the above equations, W is the concentrated load, l is the length of the beam,
E is Young's modulus and Iz is the second moment of area. As is clear from the comparison between the two expressions (1) and (2), if the conditions are the same, the maximum deflection amount Ymax of the both-end support beam is only 1/64 of the maximum deflection amount Ymax of the cantilever beam. .. For this reason, the toner layer regulating member of the present invention has a small amount of bending due to the drag force from the toner carrier side even when the plate-shaped member made of the same material as the conventional thinning blade is used. Therefore, even when this drag changes due to the fluctuation of the amount of toner coming into the pressure contact portion with the toner carrier, the change in the amount of deflection, that is, the toner passage path in the toner layer regulating member, the toner carrier, and the pressure contact portion. The change in height is much smaller than before. Therefore, even if the amount of toner that enters the pressure contact portion between the toner layer regulation member and the toner carrier fluctuates, the toner layer is regulated to a constant thickness and the toner layer is much more stable than ever before. Can be formed.

Further, the plate-shaped member is bent so that the curvature of the end portion in the width direction orthogonal to the moving direction of the surface of the toner carrier is larger than the curvature of the central portion in the same direction. When the portions are fixed, the pressure contact force with respect to the toner carrier at the widthwise end portions does not become smaller than that at the widthwise center portion.

Further, when the toner image carrier is one in which a large number of minute closed electric fields are formed in the vicinity of the surface and the charged toner is attracted and carried by the closed electric field, the toner is charged by the closed electric field. It carries in a large amount of stored toner to the pressure contact part with the toner layer regulation member and passes only the sufficiently charged toner there, so it stabilizes a good toner layer that does not contain reverse-charged toner or low-charged toner. Can be formed. Further, since the toner image carrier sucks the toner by the closed electric field, it is possible to effectively prevent the toner scattering from the end portion in the width direction.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic view showing an example of a developing device according to the present invention. First, the overall configuration and action will be clarified.
In FIG. 1, a drum-shaped photoconductor 1 which is an example of a latent image carrier is driven in the direction of arrow A, and a developing device 2 is provided facing this. In the toner container 3 of the developing device 2, a non-magnetic toner 4 in which an auxiliary agent is mixed if necessary,
That is, a non-magnetic one-component developer is contained. The low volume specific low efficiency of the toner is, for example, about 10 ⁷ to 10 ¹² Ωcm. The developing roller 5 is supported on the side plate of the toner container 3 with a part thereof exposed from the opening of the container, and the roller 5 faces the photoconductor 1 in the counterclockwise direction (arrow Y direction) in the drawing. It is driven to rotate. The developing roller 5 is one example of the configuration of the toner carrier, but a belt-shaped toner carrier can be used instead of the roller 5. A toner supply roller 6, which is an example of a toner supply member, is supported on the front and rear side plates of the toner container 3, and the roller 6 is rotationally driven counterclockwise, for example, while being in contact with the developing roller 5.

The toner 4 in the toner container 3 is carried to a toner supply roller 6 while being stirred by an agitator 7 which rotates in a clockwise direction, and then is supplied to a developing roller 5 by this roller 6. At the time of this supply, the toner is triboelectrically charged to a predetermined positive or negative polarity (negative in this example), electrostatically adheres to the peripheral surface of the developing roller 5, and is carried on the developing roller 5. The configuration and operation related to this will be described in detail later.

The toner supplied and carried on the peripheral surface of the developing roller as described above is conveyed by the rotation of the roller 5,
The thickness is regulated by the doctor plate 8 as a toner layer thickness regulating member. The structure and operation of the doctor plate 8 will be described in detail later.
Next, this toner is conveyed to the developing area 9 where the photoconductor 1 and the developing roller 5 face each other, where it is electrostatically transferred to the electrostatic latent image formed on the photoconductor 1, and the latent image is visualized. To do.
In the developing area 9, the moving directions of both the closest portion of the photosensitive member 1 and the developing roller 5 are the same forward direction.

The toner that has passed through the developing area 9 without being used for development is returned to the toner supply roller 6 while being carried by the developing roller 5. Further, the visible image formed on the photoconductor 1 is transferred to a transfer paper (not shown) and fixed on the transfer paper by a fixing device.

Now, the doctor plate 8 will be described. FIG. 1C is a perspective view showing the positional relationship between the doctor plate 8 and the developing roller 2, and FIG. 1B is a top view when the doctor plate 8 is viewed from the side. The doctor plate 8 is a flexible plate made of metal, plastic, rubber, glass fiber, carbon graphite or the like, and has a central portion in the rotation direction of the developing roller 5 as shown in FIGS. Is bent so as to project toward the surface side of the developing roller 2, and both end edges in the same direction are fixed members 9a and 9b (FIG. 1) so that the central portion presses against the surface of the developing roller 2.
(See (a)), the developing device 2 is fixed to a fixed position in the casing. In the illustrated example, the developing roller 5 is bent so that the curvature of the end portion in the width direction orthogonal to the moving direction of the surface of the developing roller 5 is larger than the curvature of the central portion in the same direction.

The central portion of the doctor plate 8 is in pressure contact with the developing roller 5, and the thickness of the toner layer carried into this pressure contact portion is regulated. The both end edges are fixed by the fixing members 9a and 9b in a state where the center portion in the width direction is bent so as to project toward the developing roller 5, and the developing roller 5 has a mechanism for supporting both ends. The displacement of the central part due to the fluctuation of the drag force received from the
(See (b)). Therefore, it is possible to stably form a thin toner layer. Further, as shown in the figure, when the end portion in the width direction orthogonal to the moving direction of the surface of the developing roller 5 is bent so as to be larger than the curvature in the center portion in the same direction, the toner is applied at the end portion in the width direction. Since the pressure contact force with respect to the carrier does not become smaller than that in the central portion in the width direction, it is possible to effectively prevent toner scattering from the end portion.

As the developing roller 5, it is possible to use one in which a large number of minute closed electric fields are formed in the vicinity of the surface, and the closed electric fields attract and carry the charged toner. For example, as shown schematically in FIGS. 2 to 4, a conductive base body made of a conductive roller 10 made of aluminum or the like and a groove 100 formed on the surface of the roller 10 are embedded and fixed. The developing roller 5 is provided with a conductive member 12, and the surface of the developing roller 5 is a conductive surface 12 which is a conductive roller surface and a groove 1.
As shown in FIG. 3, the surface of the dielectric member 11 buried in the semiconductor device 00 is regulatedly exposed, and the surface can be formed to be smooth (see also FIG. 6). The planar shape of the groove 100, that is, the surface shape of the dielectric layer 11 exposed to the outside can be appropriately set as described later, but in the example of FIGS. 3 and 4, the dielectric layer 11 forms an iris shape on the surface of the developing roller 5. And extends in the directions of arrows Z and W (X in FIG. 3 indicates the axial direction of the developing roller, and Y indicates the rotating direction of the developing roller 5, that is, the circumferential direction). The widths W1 and W2 of the dielectric member 11 and the conductive surface 12 are as small as about 30 to 500 μm, and the area ratio of the total conductive surface 12 to the total surface area of the developing roller 5 is, for example, 20 to 80.
%, Especially about 30 to 60%. As described above, the surface of the developing roller 5 includes the surface of the dielectric 11 and the conductive surface 12 in a very small area. The surface of the dielectric 11 and the conductive surface 12 may be exposed on the surface of the developing roller 5 in an irregular state.

In FIG. 3, a horizontal line is added to the dielectric 11 in order to make it easier to identify the surface 11 of the dielectric 11 (the same applies to FIGS. 7 and 8).

The numerical values shown above are the toner particle size and
It is appropriately selected in each case in consideration of the electric field strength of a minute electric field, which will be described later, and the values shown above are merely examples.

Further, a DC voltage, an alternating voltage (AC, pulse voltage, etc.), or a superimposed voltage of the both is applied to the conductive roller 10 of the developing roller 5 as needed to enhance the quality of a visible image. Alternatively, the conductive roller 10
Although it is possible to directly ground the above, the power supply 50 applies a superimposed voltage of direct current and alternating voltage in the example of FIG. The same applies to the toner supply roller 6. In this example, as the dielectric 11, a material having a polarity opposite to the counter electrode property of the toner, that is, a material that is triboelectrically charged to the positive polarity is selected.

When such a developing roller 5 is used, the toner supply roller 6 in contact with the developing roller 5 comes into contact with the dielectric 11 of the developing roller 5 and has a polarity opposite to the charging polarity of the toner ( It is composed of a material that is positively charged) and is negatively charged with the toner. In the example shown in FIGS. 1 and 2, the toner supply roller 6 includes a conductor core member 14 and a cylindrical foam body 15 laminated around the core member 14.
The foam 15 is elastically deformed and is in pressure contact with the developing roller 5. When such a toner supply roller 6 is used, the foam 15 may be made of a material that frictionally charges the dielectric 11 to the positive polarity as described above. Instead of the foam 15, a fur brush or the like known per se may be used.

The more detailed operation of the above configuration will be described below. As explained above with reference to FIG.
The portion of the developing roller that has passed the developing area 9 moves to the toner supply roller 6 and comes into contact with the roller 6. Here, the toner not carried by the development carried on the developing roller 5 is mechanically and electrically scraped off by the toner supply roller 6. At the same time, the dielectric 11 of the developing roller 5
The toner is brought into contact with the toner supply roller 6, and the friction thereof charges the toner to a positive polarity opposite to the charging polarity of the toner. At that time, even if an electrostatic afterimage due to the effect of the electrostatic latent image on the photoconductor 1 remains on the dielectric 11 on the peripheral surface of the developing roller that has passed through the developing region 9, the dielectric due to friction with the toner supply roller 6 Body 11
Is charged to almost saturation, and the amount of charge is made uniform,
The developing roller 5 can be initialized by eliminating the afterimage.

On the other hand, the toner 4 carried to the developing roller 5 while being in contact with the peripheral surface of the toner supply roller 6 is negatively charged by friction with the toner supply roller 6, as schematically shown in FIG. And supplied to the developing roller 5,
At this time, due to the friction of the developing roller 5 with the dielectric 11, the toner is further strongly negatively charged with negative polarity. At this time, the dielectric 11 of the developing roller 5 is positively charged by friction with the toner supply roller 6, and a large number of conductive surfaces 12 having a minute area are present adjacent to the dielectric 11 and the conductive surface 12 is present. 12 and the surface of the dielectric 11 are mixed. In this state,
A positive charge is selectively retained at the dielectric 11 on the surface of the developing roller 5, and a charge pattern corresponding to the surface shape of the dielectric 11 is formed on the surface of the developing roller 5. ing.

For this reason, as shown in FIG.
A large potential difference is generated between the surface of the dielectric 11 and the surface of the dielectric 11, and a closed electric field E is formed between them. That is, the developing roller 5
A charge pattern corresponding to the surface shape of the dielectric 11 is formed near the surface of the dielectric material 11. That is, innumerable minute closed electric fields (microfields) are formed in the vicinity of the surface of the developing roller 5 by the charge pattern described above. More specifically, when the electric line force representing the state of the electric field is considered, the electric line force E is formed in the space near the surface of the developing roller 5 as shown by a large number of arc-shaped lines in FIG. , The electric linear force is emitted from the developing roller 5 and is the same developing roller 5.
Then, a closed electric field is formed near the surface of the roller 5. Thus, an electric field having a large electric field gradient is formed near the surface of the developing roller.

Since the surface of the dielectric 11 and the conductive surface 12 are adjacent to each other with a minute area, the strength of each minute electric field becomes very strong due to the so-called edge effect or fringing effect (peripheral electric field effect). Due to the closed electric field, the negatively charged toner is strongly attracted to the surface of the dielectric 11 and is held on the developing roller 5 in a state in which a large amount of toner is difficult to separate. At this time, the toner is strongly triboelectrically charged by the friction between the toner supply roller 6 and the developing roller 5, and is held on the surface of the developing roller 5 by the action of a strong minute closed electric field.
A large amount of toner having a high charge is carried on the top. Moreover, when the layer thickness of the toner carried on the developing roller 5 is regulated by the doctor plate 8, the sufficiently charged toner is strongly held on the surface of the developing roller 5 by the minute closed electric field. Even if a small amount of toner is mixed, this is removed by the contact pressure with the doctor plate 8, and eventually only the toner having a large charge amount is
The electrostatic latent image is visualized as described above by being transported to the developing area 9 in a larger amount than before. The electric field between the developing roller 5 and the photoconductor 1 in the developing area 9 has a large electrode effect, and the toner on the developing roller 5 easily adheres to the photoconductor 1, so that the developing operation is efficiently performed. ..

In the vicinity of the surface of the developing roller 5 which has passed through the toner supply roller 6, as shown schematically in FIG. 5, only a small closed electric field is formed over the entire surface and an electric field which is not a closed electric field. May be mixed in the closed electric field,
In any case, since the closed electric field exists, its strength is increased and a large amount of toner can be carried.

In the example of FIG. 1, contact development is carried out in the development area 9, but the latent image may be visualized by a non-contact development method. By applying a bias of a voltage and an alternating voltage (for example, a pulse voltage), the toner is transferred to the photoreceptor 1.
Can be satisfactorily transferred to the electrostatic latent image of. Further, in the above-mentioned example, the dielectric 11 was charged to the opposite polarity to the toner, but the dielectric 11 may be charged to the same polarity as the charging polarity of the toner, and particularly a large amount of toner may be attached to the conductive surface 12.

As described above, since a large amount of sufficiently charged toner can be carried on the developing roller 5 and conveyed to the developing area 9, it is not necessary to increase the linear velocity of the developing roller as in the conventional case, and the developing roller 5 can be prevented. Even if the linear velocity of the surface is made close to the linear velocity of the individual filling of the photoconductor 1 or these are set equal,
The amount of toner conveyed to the developing area 9 is not insufficient, and insufficient density of the visible image can be prevented. If the surface linear velocities of the photoconductor 1 and the developing roller 5 are set in this way, it is possible to suppress or prevent the above-mentioned trailing edge toner deviation and further improve the quality of the visible image.

The shape of the dielectric 11 exposed on the surface of the developing roller can be appropriately formed other than the iris shape shown in FIG.
For example, as shown in FIG.
Of the conductive surface 12 extending parallel to the axial direction X of the
Are arranged to form a stripe shape, or as shown in FIG. 8, each dielectric 11 is formed in the rotation direction (circumferential direction) Y of the developing roller 5.
It is also possible to extend it in the axial direction X and form it on a grid. In these examples, charge patterns corresponding to these patterns are also formed on the surface of the developing roller 2 and thereby a minute closed electric field is formed. It Of course, in addition to this, a pattern of the dielectric 11 and the conductive surface 12 of each form can be formed on the surface of the developing roller, and the point is that a minute closed electric field that carries a large amount of toner can be formed.

When the developing roller 5 that forms a large number of minute closed electric fields on the surface is used as described above, the following actions and effects can be exhibited by using the doctor plate 8 together. Figure 9 shows the doctor plate 8
And FIG. 10 is an enlarged view of the pressure contact portion between the developing roller 5 and the developing roller 5, as viewed from the front. In FIG. 10, the toner layer thickness is regulated by the pressure contact portion by the pressure contact force P applied to the developing roller 5 by the doctor plate 8, the friction coefficient μ between the toner and the doctor plate 8, and the toner suction by the minute closed electric field of the developing roller 5. It is done with a balance of strength.
That is, only the toner that is charged to such an extent that the electrostatic force between the toner attracted to the closed electric field and the developing roller 5 overcomes the frictional force μ · P, passes through the pressure contact portion, and is exposed above the developing roller 5. Two to three toner layers are formed. The reversely charged toner and the lowly charged toner cannot pass through the pressure contact portion because the toner suction force due to the closed electric field is defeated by the friction force and is scraped off from the surface of the developing roller 5. Here, since the toner attraction force due to the closed electric field is larger than the adhesion force of the conventional non-magnetic one-component toner to the normal developing roller, a conventional thin layer blade (see FIG. 11B). Then, the toner layer regulation force tends to be insufficient. On the other hand, since the doctor plate 8 of the present embodiment has both ends supported by the mechanism of the both ends supporting beam and the both edges are fixed in the bent state as described above, a sufficient restricting force can be exerted. Further, for example, as shown in FIG. 10, when the toner pool B is formed on the upstream side in the rotation direction of the lower image roller 5 with respect to the pressure contact portion, and the drag force on the doctor plate 8 is increased, the both ends support burr is also formed as described above. Since the mechanism is a mechanism, the displacement of the central portion of the doctor plate 8 that constitutes the pressure contact portion is minute, so that the pressure contact force to the developing roller 5 side increases in accordance with the increase in this drag force. Therefore, it is most suitable as a toner regulating member used for the developing roller 5 of this type, in which such toner accumulation easily occurs due to the presence of low-charged toner and the like. The reference numeral 20 in FIG. 9 indicates that
It is an inversion prevention member that prevents the inversion of the doctor plate 8.

[0029]

According to the developing device of the first to third aspects, since the toner layer regulating member is composed of a plate-like member, the pressure contact force of the toner layer regulating member with respect to the toner image carrier is determined by the surface of the toner carrier. Can be made uniform in the width direction orthogonal to the moving direction of. Also, since this plate-shaped member has a mechanism of supporting burrs at both ends, the amount of bending due to the reaction force from the toner carrier side is smaller than that of the conventional thinning blade, and it penetrates into the pressure contact portion with the toner carrier. Even when it changes due to fluctuations in the amount of toner coming in, the change in height of the toner passage path at the toner layer regulating member, the toner carrier, and the pressure contact portion is much smaller than before, so As a result, a much more stable toner layer can be formed.

In particular, according to the developing device of the second aspect, in the plate member, the curvature of the end portion in the width direction orthogonal to the moving direction of the surface of the toner carrier is larger than the curvature of the central portion in the same direction. The above-mentioned both ends are fixed in a state of being bent so that the pressure contact force with respect to the toner carrier at the widthwise ends is not smaller than that at the widthwise central part. It is possible to effectively prevent the toner from scattering from the end portion in the same width direction of the regulation member.

Further, according to the developing device of the third aspect, as the toner image bearing member, a member in which a large number of minute closed electric fields are formed in the vicinity of the surface and the charged toner is attracted and carried by the closed electric field is used. In this case, a large amount of the toner charged by the closed electric field is carried into the pressure contact portion with the toner layer regulating member, and only the sufficiently charged toner is allowed to pass therethrough, so that the reversely charged toner or the low charging toner is charged. A good toner layer containing no toner can be stably formed. Further, since the toner image carrier sucks the toner by the closed electric field, it is possible to effectively prevent the toner scattering from the end portion in the width direction.

[Brief description of drawings]

FIG. 1A is a front view showing a schematic configuration of a developing device according to an embodiment, FIG. 1B is a perspective view showing a pressure contact state between a doctor plate and a developing roller of the developing device, and FIG. 1C is the doctor. The top view which looked at the plate sideways.

FIG. 2 is a front view showing a pressure contact state between a developing roller and a toner supply roller which can be used in the developing device.

FIG. 3 is an explanatory view for explaining a surface shape of the developing roller.

FIG. 4 is a partial cross-sectional view of a surface layer portion of the developing roller.

FIG. 5 is an explanatory diagram for explaining an electric field near the surface of the developing roller.

FIG. 6 is a perspective view of the developing roller.

FIG. 7 is an explanatory diagram illustrating a surface shape of a developing roller according to a modification.

FIG. 8 is an explanatory diagram illustrating a surface shape of a developing roller according to another modification.

9 is a front view showing a state where the developing roller and the doctor plate of FIG. 2 are pressed against each other.

FIG. 10 is an enlarged view of a pressure contact portion between the developing roller and the doctor plate.

11A and 11B are front views showing a toner regulating member according to a conventional example, respectively.

[Explanation of symbols]

2 developing device, 4 toner 5 developing roller, 6 toner supply roller 8 doctor plate, 9 photoconductors 9a, 9b fixing member, 10 conductive roller 11 dielectric

Front page continuation (72) Inventor Naoki Iwata 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Yuichi Ueno 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company

Claims (3)

[Claims] 1. A latent image carrier and the toner after the toner is carried on the surface of a toner carrier which is rotationally driven and conveyed, and the layer thickness of the toner is regulated by a toner layer regulating member which is in pressure contact with the surface. In a developing device that visualizes a latent image formed on a latent image bearing member by toner carried on a toner bearing member in a developing area where the bearing members face each other, A plate-shaped member provided with is bent in such a manner that the central portion in the moving direction of the surface of the toner carrier protrudes toward the surface of the toner carrier, and both edge parts in the same direction are fixed in place. A developing device. 2. The plate-shaped member is bent so that the curvature of the end portion in the width direction orthogonal to the moving direction of the surface of the toner carrier is larger than the curvature of the central portion in the same direction. The part is fixed.
Developing device. 3. The toner image carrier, wherein a large number of minute closed electric fields are formed in the vicinity of the surface of the toner image carrier, and the charged electric field is attracted and carried by the closed electric field. 2 developing device.