JPH041677A - Developing device - Google Patents

Abstract

PURPOSE:To suppress such a defect as toner scattering while preventing the quality of a visible image from deteriorating by charging electrostatic chargers selectively on the surface of a toner carrier and setting the ratio of the linear speed of a toner carrier and the linear speed of a latent image carrier to a specific value. CONSTITUTION:On the surface of a developing roller 5, the surface of a dielectric 11 and conductive surface 12 are both present having extremely small area, e.g. at a 0.1 - 1.0 mm pitch P of the dielectric. The dielectric 11 of the developing roller 5 is charged electrostatically by friction against a toner supply roller 6 to the negative polarity and then a large potential difference is generated between the respective conductive surfaces 12 and the surface of the dielectric 11 to produce closed electric fields between them, so that much toner having high electrostatic charges are carried on the developing roller 5. Then, the ratio vd/vp is set to 1.2 - 2.5, where vd is the linear speed of the developing roller 5 and vp is the linear speed of a photosensitive body 1. Consequently, while the scattering of the toner and toner filming are suppressed the visible image of high quality which is free from ground staining and has specific density can be obtained.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention supplies toner to a rotationally driven toner carrier, carries the toner on the surface of the carrier, and conveys the toner to the latent image carrier. In the development area where the toner carrier and the toner carrier face each other, the electrostatic latent image formed on the latent image carrier, which moves in the forward direction of the movement direction of the toner carrier surface, is transferred by the toner carried on the toner carrier. This invention relates to a developing device for visualizing images.

[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 auxiliary agent is externally added as necessary, that is, - It has been well known to employ the above-mentioned type of developing device 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, it is necessary to transport a large amount of sufficiently charged toner to a developing area, and use the toner to turn the latent image into a visible image.6 However, conventional methods of this type Depending on the developing device, it is not easy to satisfy this requirement, and improvement has been desired for some time. That is, in a conventional developing device using a one-component developer, the amount of toner that can be deposited on a toner carrier is usually about 0.1 to 0.3 .mu./d.

In the case of black toner, it is necessary to deposit approximately 0.4 to 0.5 .mu./d of toner on the transfer paper, resulting in an insufficient amount of toner. Furthermore, when color toner is used, it is necessary to deposit approximately 0.6 to 1.2 .mu./d of toner on the toner carrier, and the shortage of toner becomes even more significant.

Therefore, in the past, the speed of the toner carrier was increased, and its linear velocity was set to about 3 to 4 times the linear velocity of the latent image carrier, increasing the amount of toner conveyed to the development area and reducing the density of the visible image. was prevented.

However, with this configuration, the linear velocity of the toner carrier increases, which not only makes the toner more likely to scatter, but also increases the stress acting on the toner, which can easily cause fatigue.Moreover, the toner forms a thin film on the toner carrier over time. Toner filming, where the toner sticks to the surface, also tends to occur. Further, especially when contact development is performed, the horizontal line image of the latent image carrier becomes thinner than the vertical line image, and there is a risk that the image quality will deteriorate. Furthermore, in high-speed image forming apparatuses, it is necessary to increase the speed of the latent image carrier, but in this case, the linear velocity of the toner carrier must be increased even further, which makes it difficult for such image forming apparatuses to It was difficult to employ a developing device.

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 uses a toner carrier as a toner carrier in a developing device of the type mentioned above, which selectively retains an electric charge on its surface to form a minute closed electric field near the surface of the carrier. , using a toner carrier that attracts the charged toner by this closed electric field and carries the toner on its surface, and when the linear velocity of the toner carrier is vd and the linear velocity of the latent image carrier is vp, vp is satisfied. We propose a configuration in which each linear velocity is set.

Further, as a toner carrier, a dielectric surface and a conductive surface to which a ground or bias voltage is applied are exposed on the surface, and the dielectric is
It is advantageous to use a toner carrier which extends in a lattice shape at an angle between It is.

Further, as the toner carrier, a toner carrier in which a dielectric layer is further laminated on the dielectric material and the conductive surface can also be used.

〔Example〕

Embodiments of the present invention will be described in detail below 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 belt-shaped photoreceptor 1, which is an example of a latent image carrier, is driven in six directions indicated by arrows, and a developing device 2 is provided opposite to the belt-shaped photoreceptor 1. 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>Ω.

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 opposed to the photoreceptor 1 and rotated counterclockwise in the figure. 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 moved at a linear velocity of, for example, about 100 wrn/sec (the surface of the toner supply roller It is rotated counterclockwise at a circumferential speed (peripheral speed).

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 is frictionally charged to a predetermined polarity (in this example, a positive polarity opposite to the electrostatic latent image on the photoreceptor 1), electrostatically adheres to the circumferential surface of the developing roller 5, and is carried on the developing roller 5. be done. The configuration and operation related to this will be explained in detail later.

As described above, the toner supplied and supported on the surface of the developing roller 5 is conveyed by the rotation of the roller 5 and smoothed by the doctor blade 8, which is an example of a one-layer thickness regulating member.
Regulated to have a uniform thickness.

This toner is then 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 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 moving direction of the developing roller surface in the developing area 9 and the moving direction of the photoreceptor surface are forward directions. As can be seen from FIG. 1, the forward direction means that the photoreceptor 1 and the developing roller 5 move in the same direction at the closest point in the developing area 9. When the developing roller rotates counterclockwise and the photoreceptor 1 moves in the direction opposite to arrow A, or when the developing roller 5 moves clockwise and the photoreceptor moves in the direction of arrow A, the directions of movement of both are as follows. It will be "in the opposite direction".

This relationship holds true even when the photoreceptor is a drum or the toner carrier is a belt.

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

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 or the like, and a groove 100 formed on the surface of the roller lO.
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. (or irregularly) and its surface is smooth. Although 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, in the examples shown in FIGS. 3 and 4, the dielectric 11 extends in a grid pattern on the surface of the developing roller 5. ing. The pitch P of the dielectric 11, that is, the groove 100 is, for example, 0.1 to 1.0 m.
m, preferably about 0.2 to 0.4++w, and the ratio of the total area of the conductive surface 12 to the total surface area of the developing roller 5 is, for example, about 20 to 80%, preferably about 30 to 60%. In this way, on the surface of the developing roller 5, the surface of the dielectric 11 and the conductive surface 12 coexist in a small area.

The above-mentioned numerical values are appropriately selected each time so as to increase the electric field strength of the closed electric field, which will be described later, so that an optimum amount of toner can be deposited on the developing roller 5.

Furthermore, a bias voltage such as direct current, alternating current, direct current superimposed alternating current, or pulse voltage may be applied to the conductive roller 10 of the developing roller 5 as necessary to improve the quality of the visible image. It is also possible to configure the conductive roller 10 to be directly grounded. The same applies to the toner supply roller 6.

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

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 triboelectrically charge it to a polarity opposite to that of the toner (negative polarity), and to make the toner positive 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 this foam 15 is elastically deformed during development. It is in pressure contact with the roller 5. When such a toner supply roller 6 is used, the foam 15 is used.

As described above, the dielectric 11 may be made of a material that is triboelectrically charged to a negative polarity. 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, the toner carried on the developing roller 5 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 negative 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, Since the dielectric material 11 is charged almost to a saturated state and the amount of charge becomes uniform, there is no afterimage and the developing roller 5 is initialized.

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 supply roller 6 is triboelectrically charged to a positive polarity due to friction with the toner supply 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 more strongly to a positive polarity, and is electrostatically attached to the surface of the developing roller 5.

At this time, the dielectric body 11 of the developing roller 5 is negatively 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, negative charges are selectively held on the dielectric material 1 on the surface of the developing roller 5.

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, countless minute closed electric fields (microfields) are formed near the surface of the developing roller 5. To explain in more detail, when considering electric lines of force representing the state of the electric field, in the space near the surface of the developing roller 5.

As shown in Figure 5 by many arc-shaped lines, the electric force, I
XE is formed, the lines of electric force exit from the developing roller 5 and return to the same developing roller 5, and a closed electric field is formed near the surface of the 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 positively charged toner is strongly attracted to the surface of the dielectric 11 and 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 strong minute closed electric field on the surface of the developing roller 5, so that a high electric charge is placed on the developing roller 5. A large amount of toner with . Moreover, when the layer thickness of the toner carried on the developing roller S is regulated by a doctor blade 8 made of urethane, for example, the sufficiently charged toner is strongly held on the surface of the developing roller 5 by a minute closed electric field. Even if the toner contains toner with a small amount of charge, this
In the end, only toner with a large amount of charge is transported to the developing area 9 in a larger amount than in the past.
The electrostatic latent image is visualized as described above. 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. However, in any case, since a closed electric field exists, its strength is increased and a large amount of toner can be supported, preventing background smearing of the visible image and improving its sharpness. 8 to 15 μC to increase
0.6 to 2.0 mg/a!
A large amount of toner, preferably 0.8 to 1.2 .mu./d, can be conveyed to the developing area 9.

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. Further, in the above example, the dielectric 11 was charged to the opposite polarity to the toner, but the dielectric 11 was charged to the same polarity as the toner.

In particular, it is also possible to deposit a large amount of toner on the conductive surface 12.

As described above, since a large amount of 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 prior art.

That is, the slow speed of the developing roller 5 (peripheral speed on the roller surface) is vd, and the linear speed of the photoreceptor 1 (speed of the photoreceptor surface) is vd.
Even if the ratio Vci/vp is set to 2°5 or less, a large amount of sufficiently charged toner can be conveyed to the developing area 9 as illustrated earlier, so a toner amount shortage will occur. This prevents insufficient density of the visible image. For example, in the apparatus shown in FIG. 1, the linear velocity of the photoreceptor 1 is set to 12
0m++/5eC1 The linear speed of the developing roller 5 is approximately 170 m.
/sec. In this way, conventionally, Vd/'vp had to be set to about 3 to 4, but in the configuration according to the present invention, the value of this ratio can be set to 2.
It can be suppressed to below 5°.

By setting Vd/%J+ to 2.5 or less, various defects that conventionally occur can be avoided, such as toner scattering, early toner fatigue, toner filming on the developing roller,
The phenomenon of thinning of horizontal line images can be prevented, and the developing device according to the present invention can be used in high-speed image forming apparatuses without any problems.

As mentioned above, vd/vp can be set to 2.5 or less, and this value can be set to 1. That is, even if vd is set to vp, toner shortage in the development area can be prevented, and a decrease in the density of the visible image can be prevented.

However, when both linear velocities Vd and vp are made equal, the following problem occurs.

In the illustrated embodiment, a large amount of toner adheres to the surface of the dielectric 11 of the developing roller 5 as described above.

When the dielectric 11 and the 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 toner onto the developing roller 5. Therefore, if a developing operation is performed while rotating the developing roller 5 at the same linear speed as the photoreceptor 1, the visible image formed on the photoreceptor 1 will be affected.

There is a possibility that minute "marks" corresponding to the uneven adhesion of toner on the developing roller 5 may be formed.

Such defects are 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 improve the precision of the parts It is desirable to form a groove 100 on the surface of the roller 10 by, for example, knurling, and bury the dielectric 11 therein. However, when the developing roller is manufactured by such a method, the grooves 100. That is, since the dielectric material 11 appears with regularity on the surface of the developing roller 5, when the linear velocity ratio Vd/vp of the developing roller 5 and the photoreceptor 1 is set to 1, extremely small However, the knurling pattern appears as ``unevenness''.

In this way, if the surface of the dielectric 11 or the conductive surface 12 appears particularly regularly, the traces thereof are likely to appear in the visible image.

Furthermore, if Vd and vllll are made equal, background stains are likely to occur on the background of the photoreceptor 1. That is, the developing roller 5
When the linear velocity vd of is made larger than the linear velocity vp of the photoreceptor 1,
The toner on the developing roller 5 exerts a scavenging effect on the background portion of the photoreceptor l, thereby reducing background smudge, but if Vd and vp are made equal, no scavenging effect can be expected; Ground stains are more likely to occur.

Therefore, in the present invention, the linear velocity vd of the developing roller 5 and the photoreceptor 1 is
, vp ratio Vd/vp is 1.2 or more, preferably 1.3
The above settings were made.

If Vd is made larger than vp in this way, the development area 9
In this case, the dielectric 11 and the conductive surface 12 on the surface of the developing roller no longer face the photoreceptor 1 at a constant speed, and a relative speed is created between them, so that the patterns on the dielectric 11 and the conductive surface 12 are visible. It is possible to prevent defects that appear as "unevenness" or "marks" on the image.

Furthermore, by setting Vd/vp≧1.2, the photoreceptor 11
It has a scavenging effect on the skin, and can suppress skin stains. Figure 8 is a graph showing the background stain rank on the vertical axis and the value of vd/V on the horizontal axis. is not noticeable and poses no practical problem. As can be seen from this graph, if vd/vp is set to 1.2 or more, especially 1.3 or more, the problem of scumming does not occur.

However, when V d / V p becomes too large,
As mentioned above, various problems such as toner scattering occur.

As is clear from the previous explanation, vd/vp should be kept below 2.5. Therefore, in the present invention, vd/vp is set to 2.
5 or less and 1.2 or more, preferably 1.3 or more,
It was designed to eliminate both of these drawbacks.

With the above configuration, even when the toner is black toner,
Even when using color toner, it is possible to obtain a high-quality visible image with a predetermined density and no background smudge while suppressing toner scattering and toner filming.

By the way, the shape of the dielectric surface or the conductive surface appearing on the surface of the developing roller can be set appropriately as described above, but the shape of the dielectric material 1 appearing on the surface of the developing roller 5 in the local direction of the developing roller 5 (the surface of the roller 5) as shown in FIG. By forming a grid extending at an angle θ of 30° to 60°, preferably 456 degrees, with respect to the moving direction Y), the toner adhering to the dielectric material 11 (or the conductive surface) will move toward the axis of the developing roller 5 in the developing area 9. Since it exists in a uniformly smoothed state over the direction,
"Mura J" corresponding to the pattern of dielectric material 11 and conductive surface 12
A more specific example of a developing device including the above-mentioned developing roller 5, which can more reliably prevent the defects that appear on the image surface of the visible image, will be shown below.

(1) Developing roller The diameter D1 of the developing roller 5 shown in FIG. 6 is 25°4 m,
A groove 100 is formed on the surface by knurling,
The pitch of the groove 100 is 0,4 rm - the depth D2 (Fig. 4) is 0.1 m, the groove 1w1 (Fig. 3) is 0.15 m +
The angle θ of the grooves 100 extending in a grid pattern or the dielectric material 11 with respect to the developing roller moving direction Y is 45°. Note that the symbol X in FIGS. 3 and 5 indicates the axial direction of the developing roller 5.

The area ratio of the dielectric 11 exposed on the surface of the developing roller is 61
%, and the conductive surface is 39%. The width of the conductive surface 12 is 0.15aa+
It is.

(■) The foam material of the toner supply roller is treated with foamed polyurethane carbon, and its outer diameter is 14 mm, and its bite into the photoreceptor 1 is IW+. The surface resistance of the foam 15 is 107Ω.

(III) Doctor blade A fluorine-based resin PTFE sheet (PTFE resin tape 200 μm, manufactured by Nichas Co., Ltd.) was fixed to an elastic member made of phosphor bronze with a thickness of 0.1+m+.

(IV) Ac500V (P/P) to developing roller, 25
0Hz, DC-250°C superimposed voltage was applied. Apply a voltage of DC-250V to the toner supply member.

(V) Photoreceptor opc photoreceptor.

(■) Non-magnetic styrene acrylic toner plus charged toner, polarity control agent nigrosine, external additive Sio, fine powder 0°5 wt%.

Next, a method for manufacturing the developing roller 5 will be briefly described.

(I) First, as shown in FIG. 7(a), a metal roller (conductive roller 10) with square grooves formed on its surface is made.

The grid-like square grooves 100 are formed by square groove knurling, for example, with a pitch of 0.2 to 1.0 mm and a depth D of 0.1 mm.
0.5+m+ binding, 3 in the circumferential direction of the developing roller
Extend at an angle of 0° to 6°, especially 45°.

(II) Next, as shown in FIG. 7(b), a dielectric material 11 made of, for example, fluorine resin (Lumiflon LF200 manufactured by M Glass Co., Ltd.)
was coated on the surface of a roller 1° on which square grooves 100 were formed, and dried at 100° C. for about 30 minutes. Application thickness is groove 1
00 is completely filled in.

(III) Furthermore, the surface of the roller is cut or polished as shown in FIG.
The ratio should be between 0 and 80%.

In this way, a developing roller 5 having a substantially smooth surface is completed.

In addition, in the case of a belt-shaped toner carrier, FIG.
), (b), and (c) instead of the conductive roller 10 shown in FIG. The method is not substantially different from that shown in FIG.

It is clear that various types of toner carriers in which the dielectric material and the conductive surface are exposed on the surface can be constructed using various other methods.

Incidentally, a dielectric layer having a predetermined thickness may be further laminated on the surface of the developing roller 5 manufactured as shown in FIG. 7(c). Even when using such a developing roller.

The thickness of the dielectric 11 and the dielectric layer thereon differs depending on the groove 100 of the developing roller, and the capacitance thereof differs. Therefore, when 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 in accordance with the difference in capacitance, and a large number of minute closed electric fields can be formed in the vicinity of the surface.

According to this configuration, even when a bias voltage of alternating current or direct current superimposed on alternating current is applied to the developing roller.

It is possible to prevent charge leakage between the developing roller 5 and the photoreceptor 1, and to prevent disturbance of the electrostatic latent image due to the leakage. A belt-shaped toner carrier can also be constructed in the same manner.

Furthermore, in the embodiment shown in FIGS. 1 and 2, the dielectric 1
By charging 1 or the dielectric layer laminated thereon to a predetermined polarity, a minute electric field is formed near the surface of the toner carrier, and the toner used to visualize the latent image is supported by the closed electric field. Although the toner supply roller 6 is used as the charging means for adhering the toner to the body, other appropriate means known per se may be used, such as an independent frictional charging member, a corona discharger, or a member that injects electric charge in contact with the toner carrier. Other charging means may also be used.

Next, additional examples of the materials of the main components of the toner and the developing device will be given for reference.

Toners are generally based on resins such as polyester, BMA, polystyrene, epoxy, and phenol, and the charge polarity and amount of charge can be controlled by a polarity control agent that is added internally or externally to the toner.

Note that external addition refers to mixing an auxiliary agent such as a polarity control agent with toner particles, and internal addition refers to integrating an auxiliary agent such as a polarity control agent by kneading it into each toner particle itself.

Further, each member of the developing device is appropriately used, for example, as exemplified below, taking into consideration the charging polarity of the toner, the releasability from the toner, the durability, and the like.

Above, a developing device using a one-component developer of non-magnetic toner which is particularly suitable for color development has been exemplified, but the present invention also uses a one-component developer made of a magnetic toner to which an adjuvant is externally added as necessary. It can also be applied to the developing device used.

〔Effect of the invention〕

According to the configuration described in claim 1, a large amount of sufficiently charged toner can be transported to the development area without rotating the toner carrier at high speed as in the conventional case, and a visible image with a desired density can be formed. At the same time, conventional drawbacks associated with high-speed rotation of the toner carrier, such as toner scattering, can be prevented.
Moreover, it prevents unevenness from forming on the image surface of the visible image,
Moreover, it is possible to suppress the occurrence of scumming.

According to the configuration described in claim 2, the toner carrier can be manufactured at low cost, and deterioration in the quality of visible images can be prevented.

According to the configuration described in claim 3, it is possible to prevent leakage of charge between the toner carrier and the latent image carrier, and it is possible to form a high-quality visible image.

[Brief explanation of the drawing]

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 cross-sectional view of the IV-rV line resistance in FIG. 3. FIG. 5 is an explanatory diagram showing the lines of electric force of the minute closed electric field formed near the surface of the developing roller, and FIG. A perspective view,
FIG. 7 (a) is a schematic enlarged view of a part of the groove.
). (b) and (c) are schematic enlarged sectional views showing an example of a method for manufacturing a developing roller, and FIG. 8 is a graph showing an example of the relationship between background smear and the linear velocity ratio of the developing roller and the photoreceptor. 2...Development device 4...Toner 9...Development area 11...Dielectric material 12...Conductive surface agent Patent attorney Norio Hoshino Figure 4 Figure 5 Figure 5

Claims (3)

[Claims] (1) Supplying toner to a rotationally driven toner carrier,
The latent image carrier carries and conveys the toner on the surface of the carrier, and moves in the forward direction of the movement direction of the toner carrier surface in a development area where the latent image carrier and the toner carrier face each other. In a developing device that visualizes an electrostatic latent image formed on a body using toner carried on a toner carrier, the surface of the carrier is A small closed electric field is formed in the vicinity of the toner carrier, which attracts the charged toner and carries the toner on its surface.The linear velocity of the toner carrier is v_d, and the linear velocity of the latent image carrier is v_
A developing device characterized in that each linear velocity is set so that, when p, 1.2≦v_d/v_p≦2.5. (2) The toner carrier has a dielectric surface and a conductive surface to which a grounded or bias voltage is applied, and the dielectric is exposed at an angle of 30° with respect to the moving direction of the toner carrier surface. Claims using a toner carrier extending in a grid shape at an angle of 60° to 60° and forming a minute closed electric field between the surface of the dielectric and the conductive surface by charging the dielectric. 1. The developing device according to 1. (3) The developing device according to claim 2, wherein the toner carrier is a toner carrier in which a dielectric layer is further laminated on the dielectric material and the conductive surface.