JPH0443377A - developing device - Google Patents

Abstract

PURPOSE:To prevent the quality of a visible image from being deteriorated by using a toner carrier which carries toner by attracting electrostatically charged toner by a closed electric field and providing a vibration generating means for giving vibration to a toner layer thickness regulating member. CONSTITUTION:The toner is strongly triboelectrified by the friction of a toner supply roller 6 and a developing roller 5 and held on the surface of the roller 5 by the strong action of the fine closed electric field. Therefore, a large quantity of toner having high charge is carried on the roller 5. When the layer thickness of toner carried by the roller 5 is regulated by a doctor blade 8, the toner which is fully electrostatically charged is strongly held on the surface of the roller 5 by the fine closed electric field and only the toner which has a large quantity of electrostatic charging is carried to a developing area 9 more than in a conventional manner to visualize an electrostatic latent image. By impressing alternating voltage, namely, bias voltage periodically changed on the doctor blade 8 by a power source 50, the blade 8 vibrates with fine amplitude. Thus, the visible image of desired density is obtained, and unevenness is prevented from being formed in the image.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is directed to carrying toner on the surface of a toner carrying member and conveying the toner, regulating the layer thickness of the toner with a toner layer thickness regulating member, and then forming a latent image. The present invention relates to a developing device that visualizes an electrostatic latent image formed on a latent image carrier with toner carried on a toner carrier in a development area where a carrier and a toner carrier face each other.

[Conventional technology]

In an image forming apparatus such as an electronic copying machine, a laser printer, or a facsimile machine that obtains a recorded image by visualizing an electrostatic latent image formed on a latent image carrier, a toner to which an adjuvant is externally added as necessary, i.e. - It has been well known to employ a developing device of the above type using a component-based developer.

This type of developing device has the advantage that maintenance and management of the device can be simplified and the structure of the device can be made smaller, compared to a developing device using a two-component developer containing a carrier.

By the way, in a developing device using a -component developer,
In order to form a high-quality visible image with a predetermined density, the required amount of toner that is sufficiently charged to the required degree is transported to the development area.
It is necessary to visualize the latent image using such toner.

However, with conventional developing devices of this type, it is not easy to satisfy this requirement, and improvements have been desired for some time. That is, in a developing device using a conventional one-component developer, the amount of toner that can be deposited on the toner carrier and transported to the development area is usually 0.1 to 0.3 cm.
On the other hand, in the case of black toner, it is necessary to deposit approximately 0.4 to 0.5 .mu./d on the transfer paper, resulting in an insufficient amount of toner. In addition, when color toner is used, 0.6 to 1.2 cm is deposited on the toner carrier.
It is necessary to deposit approximately /d toner and convey it to the development area, making the toner amount shortage even more significant.

Therefore, in the past, the speed of the toner carrier was increased and the surface linear velocity of the toner carrier was set to about 3 to 4 times the surface linear velocity of the latent image carrier to increase the amount of toner transported to the development area. This prevented a decrease in the density of the visual image.

However, with this configuration, only the rear end side of the solid image formed on the latent image carrier in the direction of movement of the carrier has an abnormally high density compared to other parts, which is called "rear end toner side". This phenomenon occurs and the image quality deteriorates. This trailing edge toner shift phenomenon is a particularly serious problem in color development because, in the case of a color image, parts where the image density is abnormally high appear as different colors from other parts.

A developing device has also been proposed in which unevenness is formed on the surface of a toner carrier, and toner is filled and carried in these unevenness to increase the amount of toner conveyed to a developing area. Although the amount of toner that can be transported increases, the transported toner still contains a large amount of toner that is insufficiently charged.

This may reduce the quality of the visible image formed.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a developing device that can eliminate the above-mentioned conventional drawbacks while preventing deterioration in the quality of visible images.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a developing device of the type described at the beginning of W. As a toner carrier, a large number of minute closed electric fields are formed near the surface of the toner carrier, and the charged toner is attracted by the closed electric field. The present invention proposes a configuration in which a toner carrier carrying the toner is used and a vibration generating means for applying vibration to the toner layer thickness regulating member is provided.

Further, a regular charge pattern is formed on the surface of the toner carrier, and a minute closed electric field is formed by the pattern, increasing the surface linear velocity of the toner carrier to Vd (mm/5ee).
, the vibration frequency of the toner layer thickness regulating member is f (Hz)
) - When the pitch of the charge pattern in the rotational direction of the toner carrier is P.

It is advantageous to configure the structure so that the following relationship is satisfied.

〔Example〕

An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of a developing device according to the present invention, and first the overall structure and operation thereof will be explained.

In FIG. 1, a drum-shaped photoreceptor 1, which is an example of a latent image carrier, is driven in six directions of arrows, and a developing device 2 is provided opposite to it. In the toner container 3 of the developing device 2, there is a non-magnetic toner 4 mixed with an auxiliary agent as needed.
That is, a non-magnetic one-component developer is accommodated therein. The specific volume resistivity of the toner is, for example, about 10 7 to 10 12 Ω1.

A developing roller 5 is supported on the front and rear side plates of the toner container 3 with a portion exposed from the opening of the container.
is facing the photoreceptor 1 in the counterclockwise direction (arrow Y
direction). Although the developing roller 5 constitutes an example of a configuration of a toner carrier, a belt-shaped toner carrier may be used instead of the roller 5. Further, 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 rotated, for example, in a counterclockwise direction while being in contact with the developing roller 5.

The toner 4 in the toner container 3 is conveyed to a toner supply roller 6 while being stirred by an agitator rotating clockwise, and then supplied to a developing roller 5 by this roller 6. During this supply, the toner has a predetermined polarity (positive or negative).
In this example, it is frictionally charged to a negative polarity, electrostatically adheres to the surface of the developing roller 5, and is carried by the developing roller 5. The configuration and operation related to this will be explained in detail later.

The toner supplied and carried on the circumferential surface of the developing roller 5 as described above is conveyed by the rotation of the roller 5, and is leveled by the doctor blade 8, which is an example of a toner layer thickness regulating member, to regulate its thickness.

Next, this toner is conveyed to a developing area 9 where the photoreceptor 1 and the developing roller 5 face each other, where it is electrostatically transferred to the electrostatic latent image formed on the photoreceptor 1, converting the latent image into a visible image. become The moving direction of the closest portion of the photoreceptor 1 and the developing roller 5 in the developing area 9 is the same forward direction.

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

The above-mentioned configuration itself is the same as that of a conventional developing device, and in such a conventional developing device, it was difficult to convey a large amount of sufficiently charged toner to a developing area.

In the developing device shown therein, the developing roller 5
As shown schematically and enlarged in Figs. 2 to 4,
A conductive base consisting of a conductive roller 10 made of aluminum, for example, and a groove 100 formed on the surface of the roller 10.
The surface of the developing roller 5 has a conductive surface 12 on the surface of the conductive roller and the surface of the dielectric 11 embedded in the groove 100 in a regular pattern as shown in FIG. The surface is exposed to the surface and has a smooth surface (see also FIG. 6). The planar shape of the groove 100, that is, the surface shape of the dielectric 11 exposed to the outside, can be set as appropriate as will be explained later, but in the examples shown in FIGS. It forms a shape and extends in the directions of arrows Z and W (X in FIG. 3 is the axial direction of the developing roller,
Y indicates the rotation direction of the developing roller 5, that is, the circumferential direction). The width Wl of such dielectric 11 and conductive surface 12.

W2 is minute, for example, about 30 to 500 μm, and covers the entire conductive surface 12 with respect to the entire surface area of the developing roller 5.
The area ratio is, for example, 20 to 80%, especially 30 to 6
On the surface of the developing roller 5, the surface of the dielectric material 11 and the conductive surface 12 coexist in a very small area, such that the surface area of the developing roller 5 is about 0%. The surface of the dielectric 11 and the conductive surface 12 may be exposed to the surface of the developing roller 5 in an irregular manner.

In addition, in FIG. 3, the surface of the dielectric 11 and the conductive surface 1
2 and 2, a horizontal line is attached to the dielectric 11 (the same applies to FIGS. 7 and 8).

Each of the above-mentioned numerical values is appropriately selected each time in consideration of the particle size of the toner, the electric field strength of a minute closed electric field, etc., which will be described later, and the values shown above are merely examples.

Further, a direct current voltage, an alternating voltage (alternating current, pulse voltage, etc.),
Alternatively, a superimposed voltage of both may be applied to improve the quality of the visible image, and it is also possible to configure the conductive roller 10 to be directly grounded. In the example, the same applies to the toner supply roller 6 to which a superimposed voltage of DC and alternating voltage is applied by the power supply 50.

In this example, the dielectric 11 is selected from a material that is triboelectrically charged to a polarity opposite to that of the toner, that is, to a positive polarity.

On the other hand, the toner supply roller 6 in contact with the developing roller 5 contacts the dielectric material 11 of the developing roller 5 to frictionally charge it to a polarity opposite to that of the toner (positive polarity), and to make the toner negative polarity. Constructed from a triboelectrically charged material. In the example shown in FIGS. 1 and 2, the toner supply roller 6 is composed of a conductor core member 14 and a cylindrical foam 15 laminated around the core member 14, and while this foam 15 is elastically deformed, the developing roller It is in pressure contact with 5. When such a toner supply roller 6 is used, the foam 15 may be made of a material that triboelectrically charges the dielectric 11 to a negative polarity as described above. Instead of the foam 15, a material known per se, such as a fur brush, can also be used.

A more detailed explanation of the operation of the above configuration is as follows.

As previously explained with reference to FIG. 1, the portion of the developer roller that has passed through the development area 9 moves to and comes into contact with the toner supply roller 6.

Here, it is supported on the developing roller 5. The toner that has not been subjected to development is mechanically and electrically scraped off by the toner supply roller 6. At the same time, the dielectric 1 of the developing roller 5
1 comes into contact with the toner supply roller 6, and is charged to a positive polarity opposite to that of the toner due to the friction. At this time, even if an electrostatic afterimage remains on the dielectric 11 on the peripheral surface of the developing roller that has passed through the developing area 9 due to the influence of the electrostatic latent image on the photoreceptor 1, due to friction with the toner supply roller 6, It is possible to initialize the developing roller 5 by charging the dielectric 11 to a nearly saturated state, making the amount of charge uniform, and eliminating afterimages.

On the other hand, as schematically shown in FIG. 2, the toner 4 conveyed to the developing roller 5 while contacting the surface of the toner supplying roller 6 is triboelectrically charged to a negative polarity by friction with the toner supplying roller 6, and the developing roller At this time, due to the friction between the developing roller 5 and the dielectric material 11, the developing roller 5 is triboelectrically charged even more strongly to a negative polarity.

At this time, the dielectric body 11 of the developing roller 5 is positively charged due to friction with the toner supply roller 6, and a large number of conductive surfaces 12 with minute areas are present adjacent to this dielectric body 11. 12 and the surface of the dielectric 11 coexist. In this state, a positive charge is selectively retained on the dielectric 11 on the surface of the developing roller 5, and the surface of the developing roller 5 has a shape corresponding to the surface shape of the dielectric 11. A charge pattern is formed.

Therefore, as shown in FIG.
A large potential difference is created between the surfaces of 1, and a closed electric field is formed between them. That is, in the vicinity of the surface of the developing roller 5, countless minute closed electric fields (microfields) are formed by the above-mentioned charge pattern. Let me explain in more detail.

When considering the lines of electric force that represent the state of the electric field, lines of electric force E are formed in the space near the surface of the developing roller 5 as shown by many arc-shaped lines in FIG. The line exits the developing roller 5 and returns to the same developing roller 5, creating a closed electric field near the surface of the developing roller 5. In this way, an electric field with 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 in a small area, the strength of each small closed electric field becomes very strong due to the so-called edge effect or fringing effect (marginal electric field effect). Due to this 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 large amount in a state where it is difficult to separate. At this time, the toner is strongly triboelectrically charged due to the friction between the toner supply roller 6 and the developing roller 5, and is held by the action of a minute closed electric field applied to the surface of the developing roller 5. A large amount of highly charged toner is supported. Moreover, when the layer thickness of the toner carried on the developing roller 5 is regulated by the doctor blade 8, the sufficiently charged toner is strongly held on the surface of the developing roller 5 by a minute closed electric field. Even if toner with a small amount of charge is mixed, this is removed by the contact pressure with the doctor blade 8, and in the end, only the toner with a large amount of charge is conveyed to the developing area 9 in a larger amount than before, as described above. Visualize the electrostatic latent image. The electric field between the developing roller 5 and the photoreceptor 1 in the developing area 9 has a large electrode effect, and the toner on the developing roller 5 tends to adhere to the photoreceptor 1, so that the developing operation is performed efficiently. .

In the vicinity of the surface of the developing roller 5 that has passed the toner supply roller 6, as schematically shown in FIG. It is conceivable that 1. In any case, since a closed electric field exists, its strength is increased and a large amount of toner can be supported. - For example, in order to prevent background smearing and increase the sharpness of visible images, 0, 6 to 2.0
It is possible to convey a large amount of toner to the developing area 9, such as 1/d, preferably 0.8 to 1.2 2/d.

In the example shown in FIG. 1, contact development is performed in the development area 9, but the latent image may be visualized by a non-contact development method, and in either method, the developing roller 5 is applied with a DC voltage as described above. By applying a bias of an alternating voltage (for example, a pulse voltage), the toner can be favorably transferred toward the electrostatic latent image on the photoreceptor 1. Further, in the above-mentioned example, the dielectric 11 was charged to the opposite polarity to that of the toner, but it is also possible to charge the dielectric 11 to the same polarity as that of the toner, so that a large amount of toner adheres to the conductive surface 12 in particular. .

As described above, since a large amount of sufficiently charged toner can be carried on the developing roller 5 and transported to the developing area 9, there is no need to increase the linear speed of the developing roller as in the conventional case, and the line speed on the surface of the developing roller 5 is reduced. The speed is brought close to the linear velocity of the surface of the photoreceptor 1,
Alternatively, even if these are set equal, the amount of toner conveyed to the development area 9 will not be insufficient, and it is possible to prevent insufficient density of the visible image.

By setting the surface linear speeds of the photoreceptor 1 and the developing roller 5 in this manner, it is possible to suppress or prevent the toner shift at the trailing edge described above, and the quality of the visible image can be further improved.

Note that the shape of the dielectric 11 exposed on the surface of the developing roller can be appropriately formed other than the fleur-de-lis shape shown in FIG.
As shown in the figure, each dielectric body 11 is extended parallel to the axial direction It is also possible to extend the body 11 in the rotational direction (circumferential direction) Y of the developing roller 5 and in the axial direction X to form a lattice shape, and in these embodiments, a charge pattern corresponding to each pattern is formed on the developing roller 5. , which creates a minute closed electric field. Of course, patterns of various types of dielectric material 11 and conductive surface 12 can be formed on the surface of the developing roller, as long as a minute closed electric field supporting a large amount of toner can be formed.

By the way, as mentioned above, if the surface linear velocity of the developing roller 5 is brought closer to the surface linear velocity of the photoreceptor 1 or set equal to the surface linear velocity, an advantage can be obtained that the trailing edge toner deviation phenomenon can be prevented, but on the other hand, New problems may arise.

In the example shown in FIG. 2, a large amount of toner adheres to the surface of the dielectric 11 of the developing roller 5 as described above, and
When toner 1 and toner 4 are charged to the same polarity, a large amount of toner adheres to the conductive surface 12. That is, it is difficult to completely and uniformly adhere the toner onto the developing roller 5, and the toner adheres unevenly corresponding to the charge pattern on the surface of the developing roller. Therefore, if a developing operation is performed while rotating the developing roller 5 at the same linear speed as the photoreceptor 1 or at a linear speed close to the surface linear speed of the photoreceptor 1, the visible image formed on the photoreceptor will be , there is a possibility that extremely small "marks" may be formed corresponding to uneven adhesion of toner on the developing roller 5.

Such a problem is less likely to occur if the dielectric material 11 and conductive surface 12 exposed on the surface of the developing roller 5 are arranged irregularly, but in order to reduce the manufacturing cost of the developing roller 5 and increase the precision of the parts, it is necessary to use a conductive roller. It is desirable to form a groove 100 on the surface of the groove 10 by knurling, for example, and to bury the dielectric 11 therein. However, when the developing roller is manufactured by such a method, the grooves 100, that is, the dielectric material 11, appear regularly on the surface of the developing roller 5, as shown in FIGS. 3, 7, and 8. Therefore, the charge pattern corresponding to extremely minute knurling appears as "unevenness" on the solid image surface of the visible image. In this way, when the surface of the dielectric 11 or the conductive surface 12 appears regularly, the marks are particularly likely to appear in the visible image.

Therefore, in the illustrated embodiment, the aforementioned doctor blade 8
The blade 8 controls the layer thickness of the toner before it is supplied to the developing area 9 for development, and the blade 8 smoothes the toner on the developing roller 5 to form the visible image described above. It is designed to prevent unevenness. To explain more specifically, the doctor blade 8 is shown in FIGS. 1 and 9.
As shown in the figure, its base end is fixed to the toner container 3,
The free end is in pressure contact with the surface of the developing roller 5 via toner, and is made of a conductive and elastic plate material such as aluminum or stainless steel. A power source 50 is connected to such a blade 8, and an alternating voltage is applied by the power source 50. In this example, the power source 50 has the function of applying a bias voltage to the developing roller 5, so a DC voltage is also applied to the doctor blade 8 in addition to an alternating voltage (for example, a pulse voltage).
and the conductive roller 10 of the developing roller 5 have the same potential.

As described above, by applying an alternating voltage, that is, a periodically changing bias, to the doctor blade 8, the blade 8 vibrates with a minute amplitude.

The blade 8 is designed to ensure that such minute vibrations occur.
It is desirable to set the thickness to 0.5 mm or less.

The doctor blade 8 regulates the layer thickness of the developing roller by sweeping away the excessive toner adhered to the developing roller, and forms a toner layer necessary for development on the developing roller. During this operation, the blade 8 By vibrating as described above, the toner on the developing roller can be efficiently leveled.

That is, a large amount of toner that has adhered to the dielectric material 11 (or the conductive surface 12) can be spread over the entire surface of the developing roller 5, and the adhesion state can be made uniform.

The toner homogenized in this manner is transported to the development area 9 where the electrostatic latent image is made visible, so that unevenness corresponding to the aforementioned charge pattern does not appear on the solid image surface of the visible image. . In this way, it is possible to bring the surface linear velocity of the developing roller 5 close to the surface linear velocity of the photoreceptor 1 or to set them to the same linear velocity without any trouble, thereby obtaining a high-quality visible image.

By vibrating the blade 8, it is possible to prevent toner from sticking, and good images can be stably obtained over a long period of time.

In addition to the doctor blade 8 shown in FIGS. 1 and 9, various types of toner layer thickness regulating members can be used. For example, as shown in FIG. 10, an elastic support member made of a conductor such as metal can be used. A doctor blade 108 having a regulating part 8b made of synthetic resin, for example, at the tip of the doctor blade 108, or an eleventh
As shown in the figure, a doctor blade 208 made of a metal elastic plate curved along the circumferential surface of the developing roller 5, and a twelfth
As shown in the figure, a toner layer thickness regulating member consisting of a roller 308 that contacts the developing roller 5 while rotating in an appropriate direction can be used as appropriate. It is possible to make these vibrate by applying .

Furthermore, in the above-mentioned example, an electric current G50 that applies an alternating voltage to the toner layer thickness regulating member is used as the vibration generating means for applying vibration to the toner layer thickness regulating member. These vibration generating means can also reliably apply vibration to the roller 308 shown in FIG. 12.

Incidentally, the toner layer thickness regulating member particularly shown in FIGS. 9, 10, and 12 comes into almost linear contact with the developing roller 5 via the toner. 5, it may be difficult to level the toner uniformly depending on how the frequency of the vibration is set.

That is, as shown in FIGS. 3, 7, and 8, the surface linear velocity of the developing roller 5 is Vd (m/5ee), and the conductive surface 1 is
2 and the dielectric 11, the pitch in the developing roller rotation direction Y is set to P, and the toner layer thickness regulating members 8, 108, 30
8 vibrates in the normal direction of the developing roller (when the power source 50 is used, the frequency of its alternating voltage) is f (
Hz), when f<Vd/P, the time it takes for one pattern on the developing roller to pass through the toner layer thickness regulating member is longer than the vibration cycle of the toner layer thickness regulating member 8, 108, 308. becomes short, making it impossible to even out the toner adhering to the developing roller in accordance with the charge pattern on the developing roller. For this reason, the pattern on the surface of the developing roller appears in the solid portion of the visible image.

Therefore, in such a case, set f≧Va/P,
It is preferable to shorten the vibration period of the toner layer thickness regulating member. In this way, while one charge pattern on the developing roller passes through the toner layer forming section, the regulating members 8, 108,
Since the roller 308 undergoes one or more minute vibrations, uneven adhesion of toner on the developing roller can be reliably eliminated.

Next, a more specific embodiment of the apparatus shown in FIG. 1 will be described.

An organic photoreceptor is used as the drum-shaped photoreceptor 1, a negative latent image with a negative polarity is formed on its surface, and this is subjected to negative-positive development using negatively charged toner.

The gap between the developing roller 5 and the photoreceptor 1 is 0.12 mm, and the surface linear velocity of both is 150 m/sec.

A DC superimposed pulse bias voltage is applied to the developing roller 5, toner supply roller 6, and doctor blade 8 by a power source 5o, and its waveform has a voltage part of +100V and a voltage part of -7V.
It consists of a voltage part of 00V.

The conductive roller 10 of the developing roller 5 is made of an aluminum pipe, and has a groove width of 0.15n+ and depth of 0.1n on its surface.
The positive grooves 100 are formed by square groove knurling into a fleur-de-lis shape as shown in FIG. 4
It was set to 5°. After applying a fluororesin thereon, the surface was cut to expose the conductive surface 12 and the surface of the dielectric 11.

At this time, the pattern pitch P in the rotational direction of the developing roller 5
is 0.42 nm, so Vd/P is approximately 357 (Sat)
It is.

As the doctor blade 8, a stainless steel blade with a thickness of 0.1 mm was used. If the frequency of the pulse bias applied thereto is 3ee7 or more, the toner layer after passing through the doctor blade can be made uniform and smooth, but this bias is preferably SoO& or more and 800 Hz or less. In this state, no unevenness corresponding to the charge pattern of the developing roller appears in the solid portion of the visible image.

A high-quality visible image with no toner bias at the rear edge can be obtained.

Note that the developing roller 5 may be one in which a dielectric layer of a predetermined thickness is further laminated on the surface thereof, and even when such a developing roller is used, the thickness of the dielectric 11 and the dielectric layer thereon is the same as that of the dielectric layer. Therefore, if the dielectric layer on the surface is charged by the toner supply roller 6, a potential difference is created on the surface of the developing roller according to the difference in capacitance. , many small closed electric fields can be formed near the surface.

Further, in the above embodiment, the toner supply roller 6 was used as a charging means for charging the dielectric 11 or the dielectric layer laminated thereon to a predetermined polarity, but other independent frictional charging members or corona dischargers may be used. Any suitable charging means known per se may be used, such as an electric appliance or a member that injects charge in contact with the toner carrier.

Even when the toner carrier is formed of a belt, it can be configured in the same manner as each of the configurations of the developing roller described above.

Furthermore, in the above embodiments, a developing device using a single-component non-magnetic toner developer particularly suitable for color development was shown.
The present invention can also be applied to a developing device that uses a one-component developer made of magnetic toner to which an auxiliary agent is externally added as necessary.

〔Effect of the invention〕

According to the configuration described in claim 1, a required amount of sufficiently charged toner can be conveyed to the development area, and a visible image with a desired density can be formed. Moreover, it is possible to prevent a problem in which unevenness corresponding to the charge pattern on the surface of the toner carrier is formed in a visible image.

According to the configuration described in claim 2, it is possible to more reliably prevent the problem of uneven visible images.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a developing device, FIG. 2 is an explanatory diagram schematically showing the dielectric of the developing roller and toner particles in an enlarged manner, and FIG. 3 is an enlarged plan view of the surface of the developing roller. , FIG. 4 is an enlarged sectional view taken along line IV-■ in FIG. FIG. 7 is a perspective view schematically showing an enlarged part of a dielectric material and a conductive surface appearing on the surface of the dielectric material, and FIG. 7 and FIG. FIG. 9 is an enlarged view of the doctor blade in pressure contact with the developing roller, schematically showing the dielectric material, and FIGS. 10 to 12 are other views of the toner layer regulating member. Give an example. This is a diagram similar to FIG. 9. 2...Developing device 4...Toner 8.108,
208, 308... Toner layer thickness regulating member 9... Development area 11... Dielectric material 12...
Conductive Surface Agent Patent Attorney Norio Hoshino

Claims (2)

[Claims] (1) After carrying and conveying toner on the surface of a rotationally driven toner carrier and regulating the layer thickness of the toner by a toner layer thickness regulating member, the latent image carrier and the toner carrier face each other. In a developing device that visualizes an electrostatic latent image formed on a latent image carrier in a developing region with toner carried on a toner carrier, the toner carrier has a large number of particles near its surface. A toner carrier is used in which a minute closed electric field is formed, the charged toner is sucked by the closed electric field, and the toner is supported, and a vibration generating means is provided to vibrate the toner layer thickness regulating member. A developing device. (2) A regular charge pattern is formed on the surface of the toner carrier, a minute closed electric field is formed by the pattern, and the surface linear velocity of the toner carrier is set to V_d (mm/sec) by a toner layer thickness regulating member. The vibration frequency of is f (Hz), and the pitch of the charge pattern in the rotational direction of the toner carrier is P.
The developing device according to claim 1, which satisfies the following relationship: f≧V_d/P, where (mm).