JPH0446428B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a developing device that visualizes an electrostatic latent image of an electrophotographic device or an electrostatic recording device, and more specifically, a developing device that visualizes an electrostatic latent image of an electrophotographic device or an electrostatic recording device. It relates to a one-component type developing device that conveys developer for development.

[Technical background of the invention and its problems]

Conventionally, electrophotographic developing devices include magnetic brushes described in, for example, US Pat. No. 2,874,063, US Pat. No. 2,618,552, US Pat. No. 2,221,776, and US Pat. A number of developing devices are known based on the method, cascade method, powder cloud method, fur brush method, and the like. Among these developing devices, two-component magnetic brush developing devices and cascade developing devices, which mainly use toner and carrier as the developer, are generally put into practical use. All of these developing devices are relatively stable and can easily produce images of excellent image quality.

However, despite these excellent features, they also have common drawbacks due to the use of two-component developers. In other words, the toner acquires a triboelectric charge due to the mutual friction between the toner and the carrier, but after long-term use, the surface of the carrier becomes contaminated with the toner composition, making it impossible to obtain a sufficient charge, and the mixing ratio of the toner and carrier must be adjusted within a predetermined range, but it fluctuates and deviates from the predetermined range due to long-term use.Furthermore, iron powder or glass beads with oxidized surfaces are used as carrier materials, which are difficult to expose to light. Problems include mechanical damage to the surface of the body.

In order to avoid the above-mentioned drawbacks, various developing devices have been proposed that use a one-component developer consisting only of toner as the developer. In particular, many developing devices have been proposed that are based on a developing method using what is generally called a magnetic toner, which has magnetism as a toner. For example, developing devices such as those disclosed in US Pat. No. 3,909,258 and US Pat. No. 4,121,931 have been put into practical use. However, since developing devices using these magnetic toners use magnetic toners with relatively low resistivity, it is difficult to electrostatically transfer the developed image on the electrostatic latent image to a supporting member such as plain paper. This is especially noticeable in a humid atmosphere, and sufficient transfer cannot be obtained. Furthermore, the gap between the holder that holds the electrostatic latent image and the carrier that supplies the toner is small and the precision of the device is extremely high, and the toner contains a large amount of magnetic powder that is sensitive to magnetism. Therefore, there are disadvantages such as the inability to obtain color toner.

For this reason, developing devices that use toner that does not contain magnetic powder and have a high specific resistance have recently attracted particular attention. For example, US Pat. No. 2,895,847, US Pat.
Various developing apparatuses have been proposed based on the touchdown method, impression method, and jumping method described in Japanese Patent Publication No. 2877, Japanese Patent Publication No. 54-3624, and the like. However, these developing devices do not sufficiently overcome the above-mentioned drawbacks of developing devices based on magnetic toner. In other words, the gap between the holder that holds the electrostatic latent image and the carrier that supplies the toner must be set extremely small, and various problems regarding mechanical accuracy must be resolved in order to put the device into practical use. Must be. Furthermore, when using toner that does not contain magnetic powder, it is difficult to carry the toner on the surface of the developer carrier because magnetic force cannot be used, and therefore it is not possible to convey a certain amount of toner. . For these reasons, it has been considered difficult to put into practical use a one-component developing method using a toner that does not contain magnetic powder.

[Purpose of the invention]

Even when using a toner that does not contain magnetic powder, the present invention can support the toner on the surface of the developer carrier and transport it toward the electrostatic latent image. The object of the present invention is to provide a developing device that can obtain good developed images using a one-component developer even when the gap between the image carriers is set large, and that does not require a high degree of mechanical precision. be.

[Summary of the invention]

In the first aspect of the present invention, an electrode group consisting of a plurality of electrodes electrically insulated from each other is arranged on a developer carrier, and an alternating current voltage and a DC voltage applied to these electrodes are used to send the developer to the developer carrier. A developing device for developing an electrostatic latent image by flying a one-component non-magnetic developer, the developing device comprising means for applying an alternating voltage to some of the electrodes of the electrode group, and means for applying an alternating voltage to the remaining electrodes. The main object of the present invention is to obtain a developing device that achieves the above-mentioned object by providing a means for applying a DC voltage to generate an alternating electric field between the electrode and the electrode to which the voltage is applied.

Examples of the electrode group include a plurality of linear electrodes arranged in parallel to each other. When applying an alternating voltage or a direct current voltage to such a group of electrodes, for example, an arrangement may be mentioned in which an alternating voltage is applied to every other linear electrode, and a direct current voltage is applied to the remaining linear electrodes. be able to.

Next, the principle of the first invention of the present application is explained in FIGS. 1 and 2.
This will be explained with reference to the figures.

1 in the figure is a developer carrier, and this carrier 1
A plurality of linear electrodes 2 ₁ , 2 ₂ , 2 ₃ , 2 ₄ . . .
An electrode group consisting of the following is provided. Note that these linear electrodes 2 ₁ , 2 ₂ , 2 ₃ , 2 ₄ . . . are arranged to be electrically insulated from each other. Further, an AC power source 3 is connected to every other electrode 2 ₁ , 2 _{3 . .} . of the electrode group, and a DC power source 4 is connected to the remaining electrodes 2 ₂ , 2 ₄ .

Thus, an alternating voltage V _A is applied from the AC power supply 3 to the electrodes 2 ₁ , _{2 3} .
₄ When a DC voltage V _D is applied to..., the electrode to which the alternating voltage V _A is applied (for example, 2 ₁ ) and the DC voltage V _D
An alternating electric field is generated between the electrodes (for example 2 ₂ ) to which is applied. If, for example, negatively charged developer particles 5 exist in this electric field due to frictional electrification with the surface of the carrier 1, the particles 5 will be transferred from the electrode 2 ₂ to the electrode 2 ₁ at the moment when V _A > V _D . At the moment when V _A <V _D , a force acts from electrode 2 ₁ to electrode 2 ₂ . In this way, the developer particles 5 fly into the space near the surface of the developer carrier 1 while performing vibrational motion along the lines of electric force 6 generated between adjacent electrodes. However, as shown in FIG.
When electrostatic latent image holding members 8 having electrostatic latent images 7 . Due to the force acting on the developer particles 5, the developer particles 5 gradually approach the holder 8 while repeating reciprocating motion between adjacent electrodes, and finally adhere to the electrostatic latent images 7 to be developed.

During the above-mentioned development, since the developer particles 5 fly into the space between the carrier 1 and the holder 8 in advance due to the reciprocating movement between the electrodes, the developer particles 5 fly between the surface of the carrier 1 and the holder 8.
Even when the surface gap is large, the developer particles 5 can reach and adhere to the electrostatic latent images 6. Therefore, according to the present invention, even when the gap between the developer carrier and the electrostatic latent image holder is set large, a good developed image can be obtained, and an effect that does not require a high degree of mechanical precision can be obtained. play.

Further, in the second invention of the present application, an electrode group consisting of a plurality of electrodes that are electrically insulated from each other is arranged on the developer carrier, and the carrier is affected by alternating voltage and direct current voltage applied to these electrodes. A developing device for developing an electrostatic latent image by flying a single-component non-magnetic developer, the developing device comprising means for applying an alternating voltage to some of the electrodes of the electrode group, and means for applying an alternating voltage to the remaining electrodes. The above-mentioned purpose is achieved by providing means for applying a DC voltage to generate an alternating electric field between the electrodes to which the alternating voltage is applied, and means for generating a gradient in the voltage value of the DC voltage. In addition, the main point is to obtain a developing device that can move the developer in a fixed direction.

Next, the principle of the second invention of the present application is explained in Figures 3 and 4.
This will be explained with reference to the figures.

1 in the figure is a developer carrier, and this carrier 1
A plurality of linear electrodes 2 ₁ , 2 ₂ , 2 ₃ , 2 ₄ . . .
An electrode group consisting of the following is provided. Note that these linear electrodes 2 ₁ , 2 ₂ , 2 ₃ , 2 ₄ . . . are arranged to be electrically insulated from each other. Further, an AC power source 3 is connected to every other electrode 2 ₁ , 2 _{3 .} . . of the electrode group, and a DC power source 4 is connected to the remaining electrodes 2 ₂ , 2 ₄ . A resistor 9 ₁ is interposed between the wirings connected to the electrodes 2 ₂ and 2 ₄ , and a resistor 9 ₂ is interposed between the wirings connected to the electrode 2 ₂ on the DC power supply 4 side. ₁ by electrodes 2 ₂ , 2 ₄
A gradient occurs in the voltage value of the DC voltage applied to the

Thus, an alternating voltage V _A is applied from the AC power supply 3 to the electrodes 2 ₁ , _{2 2} .
₄ When a DC voltage V _D is applied to ..., lines of electric force 10 whose direction and density change over time at a constant period are generated between adjacent electrodes 2 ₁ and 2 ₂ , 2 ₂ and 2 ₃ , 2 ₃ and 2 ₄ occurs. At the same time, lines of electric force 11 that do not vary over time are generated from electrode 2 ₂ to electrode _{2 4} between electrodes 2 ₂ and 2 ₄ to which a DC voltage is applied with a potential gradient. However, in reality, complicated lines of electric force are generated by adding up the lines of electric force 10 and 11, but in order to make it easier to understand, we will consider these lines separately. When developer particles 5 that are negatively charged, for example, exist in these lines of electric force 10 and 11 due to frictional charging with the surface of the carrier 1, the direction and density of the developer particles 5 change over time at the constant period. It flies in an oscillatory motion along the changing lines of electric force 10, and moves from left to right along the lines of electric force 11, which do not change over time. However, when the electrostatic latent image carrier 8 having the positively charged electrostatic latent images 7 is placed on the developer carrier 1 with a desired gap as shown in FIG. 4, the flying developer particles 5 Since a force acts on the electrostatic latent image 7 of the holder 8, the developer particles 5
gradually approaches the holding body 8 while repeating reciprocating motion along the lines of electric force 10 between adjacent electrodes,
Finally, the developer particles that adhere to the electrostatic latent images 7 and are developed, but that are not developed, move to the right while flying.

According to the developing device of the second invention of the present application described above, as in the first invention of the present application, a good developed image can be obtained even when the gap between the developer carrier and the electrostatic latent image holder is set large. At the same time, there is an effect that high mechanical precision is not required. In addition, by making the developer particles fly near the surface of the developer carrier and moving them in a fixed direction, frictional charging between the developer particles and the surface of the carrier is promoted, so the developer particles are uniformly and sufficiently charged. A charge is imparted, resulting in better development of the electrostatic latent image.

Furthermore, in the third invention of the present application, an electrode group consisting of a plurality of electrodes electrically insulated from each other is arranged on the developer carrier, and an alternating voltage and a direct current voltage applied to these electrodes are applied to the developer carrier. A developing device that develops an electrostatic latent image by flying a one-component non-magnetic developer, wherein the developer carrier has a structure in which an insulating thin film is coated on a conductive substrate, and a conductive substrate is coated with an insulating thin film. The above-mentioned object is achieved by providing means for applying an alternating voltage with a DC voltage superimposed on some electrodes of the electrode group, and means for generating a gradient in the voltage value of the DC voltage. The main point is to obtain a developing device that achieves this goal.

Next, the principle of the developing device according to the third invention of the present application will be explained with reference to FIG.

1 in the figure is an insulating thin film 1 on a conductive substrate 12.
This is a carrier formed by coating No. 3. An electrode group consisting of a plurality of linear electrodes 2 ₁ , 2 ₂ , 2 ₃ , 2 _{4 .} . . that are electrically insulated from each other is provided on the insulating thin film 3 of the carrier 1 . And each of the electrodes 2 ₁ , 2 ₂ ,
2 ₃ , 2 ₄ ... are wirings 14 ₁ , 14 ₂ , 14 ₃ , 14 ₄ ...
The first busbars 15 are connected to the first busbars 15, respectively, and the busbars 15 are connected to the AC power source 3. Further, the wirings 14 ₁ , 14 ₂ , 14 ₃ , 14 ₄ ... are equipped with capacitors 16 ₁ , 16 ₂ , 16 ₃ , 16 ₄ ... to prevent direct current from flowing to the AC power supply 3. has been done. Furthermore, 17 in the figure indicates each of the electrodes 2 ₁ ,
2 ₂ , 2 ₃ , 2 ₄ ... and capacitors 16 ₁ , 16 ₂ , 16
₃ , 16 ₄ ...Wiring between 14 ₁ , 14 ₂ , 14 ₃ , 14 ₄
a second busbar cross-connected with the section;
Bus bar 17 is connected to DC power supply 4 . Resistors 9 ₁ , 9 ₂ , 9 3 for creating a gradient in the voltage value of the DC voltage are provided at the second bus bar 17 portions between the cross-connections of the wirings 14 ₁ , 14 ₂ , 14 ₃ , 14 _{4 .} ，
9 ₄ , 9 ₅ , 9 ₆ ... are interposed. Further, on the side of the carrier 1 on which the electrodes 2 ₁ , 2 ₂ , 2 ₃ , 2 ₄ . . .
are arranged facing each other with a desired gap.

When the AC power source 3 and the DC power source 4 are turned on, an alternating voltage with a DC voltage superimposed is applied to each of the linear electrodes 2 ₁ , 2 ₂ , 2 ₃ , _{2 4} . , 2 ₂ , 2 ₃ , 2 _{4 .} . . and the conductive base 12 of the carrier 1, electric lines of force 18 whose direction changes over time at a constant period are generated. In addition, each electrode 2
₁ , 2 ₂ , 2 ₃ , 2 ₄ ... have resistors 9 ₁ , 9 ₂ , 9 ₃ , 9
Since _an alternating voltage with a current and voltage superimposed with _a potential gradient _is applied by _4,95 , _... Lines of electric force 19 that do not change over time are generated from 2 to ₂ toward the electrode 2, etc. However, in reality, complex lines of electric force are generated by adding up the lines of electric force 18 and 19, but here, Let's consider them separately to make them easier to understand. For example, developer particles 5 which are negatively charged due to frictional charging with the surface of the carrier 1 in these electric lines of force 18 and 19
When the developer particles 5 are conveyed, the developer particles 5 fly in the space near the surface of the carrier 1 while vibrating along the electric lines of force 18 whose direction changes over time at the above-mentioned constant period. It moves from the electrode 2 ₁ to the electrode 2 ₄ side (from left to right) along the lines of electric force 19 that do not change. However, when the electrostatic latent image 7 formed on the holder 8 moves to the development area of the carrier 1, a force toward the electrostatic latent image 7 acts on the flying developer particles 5. The particles 5 adhere to the electrostatic latent image 7 and are developed, and the developer particles 5 that do not contribute to the development move to the right while flying.

During the development described above, the developer particles 5 are attached to each electrode 2.
₁ , 2 ₂ , 2 ₃ , 2 ₄ and the conductive base 12 of the carrier 1, the surface of the carrier 1 is Even if the gap between the surface of the holder 8 and the surface of the holder 8 is large, the developer particles 5 can reach and adhere to the electrostatic latent image 7. Therefore, even when the gap between the carrier 1 and the holder 3 is set large, a good developed image can be obtained and a high degree of mechanical precision is not required. Furthermore, since the developer particles 5 can be transported while being suspended, frictional charging between the developer particles 5 and the surface of the carrier 1 is promoted, and it is possible to impart a uniform and sufficient charge to the developer particles 5. As a result, a better developed image can be formed.

[Embodiments of the invention]

Embodiments of the invention of Application 1 are shown in FIGS. 6 and 7 below.
This will be explained with reference to the figures.

21 in the figure is an aluminum drum having a Se--Te based photosensitive layer 22 as a holder. This drum 21 rotates in the direction of the arrow at, for example, 80 mm/sec. Further, on the photosensitive layer 22 on the surface of the drum 21, an electrostatic latent image 22 positively charged with, for example, +300 to +800V is formed. Such an electrostatic latent image 23... is, for example, the photosensitive layer 2 on the surface of the drum 21.
It is formed by uniformly charging with a well-known corona discharger or roller charger, etc., and then performing imagewise exposure. Other than this, a pattern depending on the image to be formed may be formed using a cathode ray tube or laser light, or a dot pattern of electrostatic charges may be formed using a needle electrode light emitting diode or the like. Note that the aluminum drum 21 is grounded.

Further, reference numeral 24 in the figure is a developer carrier roll that is arranged opposite to the drum 21 and rotates in the direction of the arrow.
It is made by coating the surface of a 0 mm hollow aluminum roll with polyimide resin. Further, on the surface of the carrier roll 24, as shown in FIG. 7, a plurality of copper wire electrodes 25 ₁ are insulated from each other.
.about.25 ₃₂ are arranged parallel to each other in the longitudinal direction of the roll 24 in a comb shape. In other words, the right end of every other linear electrode 25 ₁ ... 25 ₃₁ is the ring-shaped first
The left ends of the remaining linear electrodes 25 ₂ . . . 25 ₃₂ are integrally connected to a ring-shaped second common electrode 27 . These linear electrodes 25 ₁ to 25 ₂₀ are formed, for example, by depositing a copper film on the polyimide coating of the carrier roll 24 and selectively etching it. Each of these linear electrodes 25 ₁ to 25 ₃₂ has a width of 0.3
mm, thickness is 5 μm, and the distance between the electrodes is 0.3 mm. An AC power source 28 is connected to the first common electrode 26 via a brush (not shown). Further, a DC power source 29 is connected to the second common electrode 27 via a brush (not shown).

In addition, 30 in the figure is Nato 31 as a developer.
It is a hotspa that supplies. This toner 31 is insulating and its components include styrene resin, acrylic resin,
It is a general product in which a coloring agent such as carbon black, a pigment, or a charge control agent such as a dye is blended into a resin such as an epoxy resin, a polyester resin, a maleic resin, or a copolymer thereof in a desired ratio. Further, an elastic blade 32 for negatively charging the toner 31 is provided at the rear stage of the hopper 30 in the rotational direction of the carrier roll 24 .

According to this configuration, when the carrier roll 24 is rotated in the direction of the arrow, the toner 31 comes into contact with the carrier roll 24 and the elastic blade 32 and is negatively charged due to friction. Along with the rotation of the carrier roll 24, 600 V is applied from the AC power supply 28 to every other linear electrode 25 ₁ ... 25 ₃₁ via the first common electrode 26.
_An alternating voltage _of
When _a DC voltage _{of 100V} is applied _{to 2 ,} electric lines _of force (electric field ) occurs. However, when the negatively charged toner 31 is transported by the elastic blade 32 to the area of the electric lines of force, the toner 31 vibrates along the lines of electric force and vibrates near the surface of the carrier roll 24. Fly through space. The drum 21 rotates and the photosensitive layer 22 on the surface of the drum 21 rotates.
When the electrostatic latent image 23 formed at While repeating reciprocating motion along the lines of electric force between adjacent electrodes, the photosensitive layer 22
It gradually approaches the electrostatic latent image 23, and eventually adheres to the electrostatic latent image 23 and is developed.

Therefore, according to the first invention of the present application, there are various effects listed below.

Sufficient development is possible even if the gap between the photosensitive layer 22 on the surface of the drum 21 that holds the electrostatic latent image 23 and the developer carrier roll 24 that supplies toner is selected within the range of, for example, about 0.5 to 5 mm. Layout design and assembly technology for setting gaps with high precision are no longer required, reducing equipment costs and simplifying maintenance.

By applying an alternating voltage and a direct current voltage to adjacent electrodes, electric lines of force can be generated between the adjacent electrodes, making it possible to levitate the nato with an extremely simple circuit configuration.

Since the photosensitive layer on the surface of the drum is not in contact with the carrier roll, mechanical damage to the photosensitive layer caused by toner and aggregation of toner on the carrier roll can be prevented. Moreover, since toner can be attached to the next electrostatic latent image without disturbing the toner area (developing area) that has previously adhered to the photosensitive layer, the multicolor copying process is facilitated.

Since only the charged toner is attached to the electrostatic latent image on the photosensitive layer, capri-free development is possible.

Since development is performed using a flying toner layer, an image with high gradation, fine line reproducibility, and edge effect can be obtained by transferring to plain paper or the like. Moreover, since the toner is dispersed and attached to the electrostatic latent image in the form of primary particles, a dense image can be obtained.

Since the drum having the photosensitive layer can be prevented from being destroyed by electric discharge, the durability of the drum having the photosensitive layer as a holder can be improved.

Note that the first invention of the present application is not limited to the case where the carrier roll provided with the linear electrodes shown in FIG. 7, which was explained in the above embodiment, is used. For example, as shown in FIG. 8, island-shaped or dot-shaped electrodes 25a..., 25b... are formed on the surface of the carrier roll 24, and one electrode 25a... is connected to an AC power source 28, and the other electrode 25
A structure may be adopted in which the DC power supply 29 is connected to b. According to such a configuration, the vibration motion of the toner becomes more random, and a more uniform developed image can be formed.

Next, an embodiment of the second invention of the present application will be described with reference to FIGS. 9 and 10. Note that the same members as in FIGS. 6 and 7 are designated by the same reference numerals, and the description thereof will be omitted.

24 in the figure is a developer carrier roll rotating in the direction of the arrow, and a plurality of copper wire electrodes 25 ₁ to 2 are electrically insulated from each other on the surface of this roll 24.
5 _{and 20} are arranged parallel to each other in the longitudinal direction of the roll 24. The right ends of every other linear electrode 25 ₁ . . . 25 ₂₉ among these linear electrodes are integrally connected to a ring-shaped common electrode 33 . Further, an AC power source 28 is connected to this common electrode 33 via a brush (not shown). An insulating sleeve 34 is fixed within the carrier roll 24 and arranged concentrically with respect to the roll 24. One end of this insulating sleeve 34 protrudes a little from the carrier roll 24, and a C-shaped resistor 35 with a portion cut out is formed on the outer peripheral surface of the protruding sleeve 34. Furthermore, a conductor 3 is provided at the left end of the remaining linear electrodes 25 ₂ ... 25 ₂₀ .
6... are connected to each other, and these conductor wires 36
The other end of the resistor 35 is connected to the surface of the resistor 35 via a brush (not shown). Both ends of the C-type resistor 35 are connected to a DC power source 29.

According to this configuration, when the carrier roll 24 is rotated in the direction of the arrow, the toner 31 comes into contact with the carrier roll 24 and the elastic blade 32 and is negatively charged due to friction. Along with the rotation of the carrier roll 24, an alternating voltage of 600 V is applied from the AC power supply 28 to every other linear electrode 25 ₁ ... 25 ₃₁ via the common electrode 33, and from the DC power supply 29 to the resistor 35 and the conducting wire 36. ... through the remaining linear electrodes 25 ₂ ... 25 ₃₂
When a DC voltage of 100 V is applied to the electrodes, lines of electric force whose direction and density change over time are generated at a constant period between the adjacent electrodes 25 ₁ and 25 ₂ , 25 ₂ and 25 ₃ ...25 ₃₂ and 25 ₁ . At the same time, lines of electric force that do not vary over time are generated in the counterclockwise direction between the electrodes 25 ₂ and 25 ₄ . . . 25 ₃₂ and 25 ₂ to which a DC voltage is applied with a potential gradient by the resistor 35. However, when the negatively charged toner 31 is conveyed by the elastic blade 32 to the area of each of the lines of electric force, the toner 31 vibrates along the lines of electric force that change over time while moving toward the carrier roll. While flying in the space near the surface of Roll 24, it flies in the clockwise direction (Roll 2
It moves in the same direction as the rotation in step 4). When the drum 21 rotates and the electrostatic latent image 23 formed on the photosensitive layer 22 on its surface is transferred to the flying toner layer of the carrier roll 24, the toner 31 in the toner layer is transferred to the electrostatic latent image 23. Since a force is applied toward the latent image 23, the toner 31 gradually approaches the photosensitive layer 22 while repeating reciprocating motion along the lines of electric force between adjacent electrodes, and eventually adheres to the electrostatic latent image 23. Toner 31 that has been developed and has not been developed
is transported in the clockwise direction by time-invariant electric field lines.

According to the second invention of the present application described above, in addition to having the same effects as the first invention of the present application, since the toner can be moved in a fixed direction while flying, frictional charging between the toner and the surface of the carrier roll is promoted, and the toner is is provided with a uniform and sufficient charge, and as a result, the electrostatic latent image can be developed better.

Next, an embodiment of the third invention of the present application will be described with reference to FIG. 11. Components similar to those in FIGS. 6 and 7 are given the same reference numerals and their explanations will be omitted.

Reference numeral 24 in the figure is a developer carrier roll that rotates in the direction of the arrow and is placed opposite the drum 21. This carrier roll 24 is, for example, a hollow aluminum roll with an outer diameter of 40 mm, and its surface and end surfaces are coated with polyimide resin. It is made by coating a thin film. Further, on the surface of the carrier roll 24, a plurality of copper wire electrodes 25 ₁ are electrically insulated from each other.
.about.25 ₁₆ are wired in parallel to each other in the longitudinal direction of the roll 24. These copper wire electrodes 25 ₁ to 2
5 ₁₆ is formed, for example, by depositing a copper thin film on a polyimide resin thin film on the outer peripheral surface of the carrier roll 24 by vacuum evaporation or the like, and selectively etching this. Each of these linear electrodes 25 ₁ to 25 ₁₆ has a width of 0.3 mm, a thickness of 5 μm, and a distance between the electrodes of 0.3 mm.

Further, in a region within the carrier roll 24 facing the drum 21, five curved power feeding electrodes 37 ₁ to 37 ₅ are fixed to the inner circumferential surface of the roll 24 at regular intervals. These power supply electrodes 37
Conductive wires 36 ₁ to 36 14 extending from the end faces of the linear electrodes _{25 1 to 25 16 to} the center of the roll 24 are brought into contact with the electrodes _{37 1 to} 37 ₅ . Note that brushes (not shown) are attached to the free ends of these conductors 36 ₁ to 36 ₁₆ .
The power feeding electrodes 37 ₁ to 37 ₅ are wires 38 ₁ to 38 ₅
The first busbars 39 are connected to the AC power supply 28 via the first busbars 39, respectively.
Further, a second bus bar 40 is cross-connected to the wirings 38 ₁ to 38 ₅ , and one end of the second bus bar 40 is connected to the DC power supply 29 and the other end is connected to the ground. Each wiring 38 ₁ to 38 ₅ between the first bus bar 39 and the cross-connection portion and each wiring 3 between the cross-connection portion
Capacitors 41 ₁ to 41 ₅ are interposed in the portions 8 ₁ to 38 ₅ , respectively _.
41 ₅ prevents the DC current from the DC power supply 29 from flowing to the AC power supply 28 . Furthermore, _{a second}
The power feeding electrodes 37 ₁ to 3 are provided at the bus bar 40 portion, respectively.
Resistors 35 ₁ to 35 ₄ are interposed to create a gradient in the voltage value of the DC voltage applied to 7 ₅ .

According to this configuration, when the carrier roll 24 is rotated in the direction of the arrow, the toner 36 comes into contact with the carrier roll 24 and the elastic blade 32 and is negatively charged due to friction. When the AC power supply 28 (for example, 600V) and the DC power supply 29 (for example, 500V) are turned on together with the rotation of the carrier roll 24, an alternating voltage with a DC voltage superimposed is applied to each of the power supply electrodes 37 ₁ to 37 ₅ . As the roll 24 rotates _, conductive wires (for example _, 37 ₁
A similar alternating voltage is applied to the linear electrodes (for example, 25 _{1 to} 25 _{5 ) connected via the electrodes 25 1 to 25 5} ).
Therefore, each linear electrode 25 to which an alternating voltage is applied
₁ to 25 ₅ and an aluminum roll (not shown) of the carrier roll 24, electric lines of force are generated whose direction changes over time at a constant period. Moreover, each linear electrode 25 ₁ connected to each power feeding electrode 37 ₁ to 37 ₅
~ ₂₅₅ is applied with an alternating voltage in which a DC voltage with a potential gradient is superimposed by the resistors _{351 to 354} . 25 ₄ , electrode 24
_From the electrode 25 _{3 ,} time-invariant lines of electric force are generated, particularly in the direction opposite to the rotation of the roll 24 . Note that the linear electrodes connected to the power feeding electrodes 36 ₁ to 36 ₅ change depending on the rotation of the carrier roll 24, but in any case, the linear electrodes on the surface of the roll 24 corresponding to the feeding electrodes 36 ₁ to 36 ₅ The electric lines of force are generated in the area of the photosensitive drum 21, that is, the area facing the photosensitive drum 21. However, when the negatively charged toner 31 is conveyed by the elastic blade 32 to the area of the lines of electric force, the toner 31 vibrates along the lines of electric force whose direction changes over time at a constant cycle. while flying close to the surface of the area. When the drum 21 rotates and the electrostatic latent image 23 formed on the photosensitive layer 22 on its surface is transferred to the floating toner layer, the toner 31 in the floating toner layer is moved by a force toward the electrostatic latent image 23. acts, the electrostatic latent image 2
The toner 31 that adheres to the roller 24 and is not developed is transported in the same direction as the roll 24 by electric lines of force that do not change over time.

Therefore, the developing device of the third invention of the present application has the same effects as the above-mentioned second invention of the present application.

In the above embodiments, the carrier roll was composed of an aluminum roll and a thin nylon resin film coated on the outer surface of the roll, but the present invention is not limited thereto. For example, the conductive roll may be made of copper, stainless steel, phosphor bronze, etc., and the thin film may be made of fluororesin, vinylidene chloride resin, polyimide resin, etc.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to increase the gap between the holder that holds the electrostatic latent image and the carrier that supplies the developer, and to perform good development without fogging. In addition, it is possible to provide a developing device that can prevent mechanical damage to the holder.

[Brief explanation of the drawing]

1 and 2 are schematic diagrams for explaining the principle of the developing device according to the first invention of the present application, and FIGS. 3 and 4 are schematic diagrams for explaining the principle of the developing device according to the second invention of the present application. 5 is a schematic diagram for explaining the principle of the developing device according to the third invention of the present application,
FIG. 6 is a schematic diagram of a developing device showing an embodiment of the first invention of the present application, FIG. 7 is a perspective view of a member including the carrier roll of FIG. 6, and FIG. A perspective view of a member including a carrier roll showing an example of
FIG. 9 is a schematic diagram of a developing device showing an embodiment of the second invention of the present application, FIG. 10 is a perspective view of a member including the carrier roll of FIG. 9, and FIG. 11 is a diagram according to the third invention of the present application. FIG. 1 is a schematic diagram showing an example of a developing device. 1...Developer carrier, 2 ₁ to 2 ₄ , 25a, 26
b, 25 ₁ to 25 ₃₂ ... linear electrode, 3, 28 ...
AC power supply, 4, 29... DC power supply, 5... Developer particles, 6, 10, 11, 18, 19... Lines of electric force, 7, 23... Electrostatic latent image, 8... Holder, 9 ₁
~9 ₅ , 35, 35 ₁ ~ 35 ₄ ...Resistor, 12...
... Conductive substrate, 13 ... Insulating thin film, 21 ... Drum, 22 ... Photosensitive layer, 24 ... Developer carrier roll, 30 ... Hopper, 31 ... Toner, 32 ...
...Elastic blade, 37 ₁ to 37 ₅ ... Power feeding electrode,
16 ₁ to 16 ₄ , 41 ₁ to 41 ₅ ... Capacitors.

Claims (1)

[Scope of Claims] 1. An electrode group consisting of a plurality of electrodes electrically insulated from each other is arranged on a developer carrier, and an alternating voltage and a DC voltage applied to these electrodes are used to send developer to the developer carrier. A developing device for developing an electrostatic latent image by flying a one-component non-magnetic developer, the developing device comprising means for applying an alternating voltage to some of the electrodes of the electrode group, and means for applying an alternating voltage to the remaining electrodes. 1. A developing device comprising means for applying a DC voltage to generate an alternating electric field between the electrode and the electrode to which the voltage is applied. 2. The developing device according to claim 1, wherein the electrode group includes a plurality of linear electrodes arranged in parallel to each other. 3. The developing device according to claim 1, wherein an alternating voltage is applied to every other linear electrode, and a direct current voltage is applied to the remaining linear electrodes. 4. An electrode group consisting of a plurality of electrodes electrically insulated from each other is arranged on a developer carrier, and one-component non-magnetic material is sent to the developer carrier by an alternating voltage and a direct current voltage applied to these electrodes. A developing device that develops an electrostatic latent image by flying a developer, the device comprising means for applying an alternating voltage to some of the electrodes of the electrode group, and electrodes to which the alternating voltage is applied to the remaining electrodes. 1. A developing device comprising: means for applying a DC voltage to generate an alternating electric field between said DC voltage; and means for generating a gradient in the voltage value of said DC voltage. 5. The developing device according to claim 4, wherein the electrode group includes a plurality of linear electrodes arranged in parallel to each other. 6. The developing device according to claim 4, wherein an alternating voltage is applied to every other linear electrode, and a direct current voltage is applied to the remaining linear electrodes. 7. An electrode group consisting of a plurality of electrodes electrically insulated from each other is arranged on a developer carrier, and one-component non-magnetic material is sent to the developer carrier by alternating voltage and direct current voltage applied to these electrodes. A developing device that develops an electrostatic latent image by flying developer, wherein the developer carrier has a structure in which a conductive substrate is coated with an insulating thin film, and one of the electrodes on the thin film is A developing device comprising means for applying an alternating voltage in which a DC voltage is superimposed to some electrodes, and means for generating a gradient in the voltage value of the DC voltage. 8. The developing device according to claim 7, wherein the electrode group consists of a plurality of linear electrodes arranged in parallel to each other.