JPH06301280A - Developing device - Google Patents

Abstract

PURPOSE:To provide a developing device capable of stably attaining the reversal development of a sufficient density without fogging under the vibrating electric field of a developing area by efficiently making a developer cloudy with a wire like electrode and supplying the developer to the developing area, without the occurrence of the heaping of the developer on the wire like electrode in the gap of the developing area. CONSTITUTION:In the developing device, the wire like electrode is provided in the gap on the upstream side of the developing area and in the reversal development of an electrostatic image on an image forming body 1 by the soaring up of the developer to the image forming body from a one-component developer layer on a noncontact developer carrier, under the vibrating electric field of the developing area, when the DC components of bias voltages applied to a developer carrier 4 and the wire like electrode are defined as SD and GD, respectively and the potential of a destaticization part by the image exposure of the charged surface of the image forming body 1 is defined as LD, each absolute value satisfies 0.5 SD<GD<1.5SD and LD<GD or the DC components of the bias voltages applied to the wire like electrode 8 and the developer carrier 4 are applied from the same DC power source.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for use in an image recording apparatus such as an electrophotographic copying machine or a printer, and more particularly in a recording apparatus for forming a multicolor image composed of a plurality of toner images on an image forming body. Regarding the apparatus, in detail, a layer of a developer mainly composed of toner particles is formed on the surface of the developer carrier so as not to contact the surface of the image forming body, and the developer carrying body is formed in the developing area facing the image forming body. The present invention relates to a developing device that causes toner particles to fly from a developer layer under such an oscillating electric field and adheres to the electrostatic image of an image forming body.

[0002]

2. Description of the Related Art As a developer device as described above, a plurality of linear electrodes extending in a direction perpendicular to the developer transporting direction of a developer transporting body are arranged in a gap in a developing zone, and the linear electrodes are arranged. A developing device in which a centrifugal force due to an alternating electric field is formed in a developing area by applying an alternating voltage such that polarities of adjacent linear electrodes are opposite to each other to fly the toner particles It is known from Japanese Patent Publication No. 56-27158. Further, an oscillating electric field is formed in the developing area by applying a bias voltage having a DC component and an AC component to the developer carrier, and a grid composed of a plurality of linear electrodes as described above is provided in the gap of the developing area. By providing the gap between the developer carrier and the grid, which is narrower than the gap in the developing region, a force from the developer carrier side to the grid side is applied to the oscillating electric field or the toner particles having a strength higher than the oscillating electric field in the developing region. Japanese Patent Laid-Open Publication No. 57-198470 discloses a developing device in which a unidirectional electric field is formed to accelerate the flight of toner particles in the developing area. Further, there is a developing device in which an electrode is provided in a gap in the developing area and an alternating voltage is applied to the electrode to cloud the developer layer of the developer transport body.
It is known by the publications 1678 and 4-115264.

In the developing device described in Japanese Patent Laid-Open No. 56-27158, it is not only difficult to accurately arrange parallel linear electrodes for forming a uniform centrifugal force in the developing area having a narrow gap, but Since the linear electrode and the image forming body are largely separated from each other as compared with the linear electrode and the developer carrying body, an oscillating electric field is less likely to be formed between the image forming body and the linear electrode, and the linear electrode and the image forming body are separated from each other. There is a problem that it is difficult to obtain sufficient developing density because the flying of the toner particles is insufficient only by the centrifugal force formed.

The developing device described in Japanese Patent Laid-Open No. 57-198470 discloses toner particles charged to the same polarity as that of the image forming body at the potential lowering portion where the image exposure by the laser beam scanner of the charged surface of the image forming body is incident. It is also used in the development for adhering toner, that is, in the reverse development suitable for forming a multicolor image or a high-quality image on the image forming body, but the accuracy of the parallel gap of the linear electrodes is JP-A-56-27158. Although it is relatively easy to provide the grid because it is not so demanded, it is still difficult to provide the grid in the gap of the narrow developing area. Absolute value H _D [V] of the charging potential, absolute value L of the potential of the static elimination portion on which image exposure is incident
_D [V], the absolute value G _D of the DC voltage of the bias voltage applied to the grid [V], the absolute value S _D of the DC component of the bias voltage applied to the developer carrying member (V), H _D> S _D >
Since the condition of satisfying the relationship of L _D ≧ G _D is satisfied, the developer is likely to be clogged due to the accumulation of the developer on the grid and the development stability is poor, and a multicolor image is formed on the image forming body. In the image recording apparatus described above, there is a further problem that the previously developed developer flows back into the grid and easily mixes into the developing apparatus for later development.

The developing devices described in JP-A-3-121678 and JP-A-4-115264 are similar to those disclosed in JP-A-56-27158, and there is a space between the image forming body and the developer transport body. It is difficult to form an oscillating electric field, the force for moving the generated developer cloud to the image forming body is insufficient, and it is difficult to obtain a sufficient developing density without fogging. Particularly in the case of reversal development, it is necessary to set the potential of the developer carrier to a potential higher than the potential of the electrodes in the developing region, which easily causes electrode stains, which lowers development performance and stains in the machine and multicolor image recording apparatus. Then, toner particles of different colors are more likely to be mixed in the developing device. Further, if an AC bias voltage is applied to the developer carrier to obtain a sufficient development density, the AC bias voltage applied to the developer carrier and the electrode has the same phase for smooth toner flight. There is a problem that the bias power supply device becomes complicated because of the need for the phase control device of otherwise, otherwise the developer is not clouded smoothly because the phases of both AC bias voltages are different, and the development failure is likely to occur. is there.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problem of the developing device in which the electrode for clouding the developer is provided in the gap of the developing area as described above. An object of the present invention is to provide a developing device capable of efficiently forming a cloud of the developer without causing deposition of the developer on the electrodes and stably performing development with a sufficient density without fogging by reversal development.

[0007]

DISCLOSURE OF THE INVENTION The present invention is directed to a developer transporting body for transporting a developer mainly composed of toner particles by forming a layer on the surface of the developer which does not contact the surface of the image forming body and transporting the developer to the image forming body. A linear electrode extending in a direction perpendicular to the transport direction is disposed in a gap where the body faces each other, and a bias voltage having a DC component and an AC component having the same polarity as the charging of the surface of the image forming body is applied to the developer transport body. Main bias power supply for supplying the bias voltage having a direct current component of at least the same polarity as the charging of the image forming body surface to the linear electrode, and the bias voltage is applied to the developer carrier and the linear electrode, respectively. In a developing device in which toner particles are applied to cause toner particles to fly from the developer layer on the surface of the developer transporter and adhere to the electrostatic latent image on the surface of the image forming body, a DC component absolute value S _D [V] of the bias voltage of the developer transporter is applied. ，
Absolute value of DC component of bias voltage of linear electrode G _D [V],
Potential absolute value L _D of static eliminator incident image exposure to the charged surface of the image forming body [V] satisfies the relation of 0.5S _D <G _D <1.5S _D and L _D <G _D, imaging A developing device characterized in that the toner particles charged to the same polarity as the body charge are attached to the charge eliminating portion of the image forming body, or the DC power source portion of the bias power source of the developer carrier is a bias power source of a linear electrode. The developing device is characterized in that the above-mentioned object is achieved by these configurations.

[0008]

In the first developing device of the present invention, the AC component of the bias voltage of the developer carrier forms an oscillating electric field of high strength in a narrow gap (vibration region) with the linear electrode to cloud the developer. Promote the transformation. The formed cloud is guided to the developing area between the developer transport body and the image forming body by the inertial force due to the rotation of the developer transport body and the centrifugal force formed by the oscillating electric field, and is responsive to the electrostatic latent image. Develop.

Here, since the linear electrode in the developing region acts only on clouding of the developer, the range of use of the DC bias that can be applied to the linear electrode is greatly widened as compared with the prior art, and G _D It becomes possible to use even in the range of> S _D , and the absolute value G _D of the direct current component of the bias voltage of the linear electrode is greater than 1/2 of the absolute value S _D of the direct current component of the bias voltage of the developer carrier and is 1.5 times or more. Small range, preferably 0.7S _D ≤ G _D ≤
In the range of 1.3 _{SD and in} the range where G _D is larger than the charge eliminating portion potential L _D that is incident on the charged surface of the image forming body during the image exposure, the toner particles charged to the same polarity in the developer cloud are charged to the image forming body. The toner can be sufficiently adhered to the charge eliminating portion, and the developer is not deposited on the linear electrode. Therefore, a clear toner image having a dot structure can be stably formed.

On the other hand, the direct current component G _D of the bias voltage of the linear electrode is less than 1/2 of the direct current component S _D of the bias voltage of the developer carrier, or the charge eliminating portion potential L _D of the image forming body.
If it is less than or equal to the above, toner particles will be deposited on the linear electrode, and development failure and development performance will be likely to occur. Further, in a multicolor image recording apparatus that forms a multicolor image on an image forming body, the developer that has been previously developed is attracted to the linear electrode and easily mixed into a developing apparatus that performs development afterwards. When G _D ≧ 1.5 _SD , the developer is pressed down by the potential difference from the linear electrode, the clouding of the developer layer is not performed, and the development density sharply decreases.

The second developing device of the present invention, in the case of G _D = S _D in the first developing device, shows the DC component of the bias voltage applied to the developer carrier and the bias voltage applied to the linear electrode. This is a developing device that is supplied from a common power source, whereby a sufficient developing density can be obtained without depositing the developer on the linear electrodes, and at the same time, the bias power source device is simplified. be able to.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings.

1 and 3 to 5 are partial structural views of an image recording apparatus showing an example of the developing apparatus of the present invention, and FIG.
6 is a view showing an example of an AC component of the bias voltage of the developer carrier, FIG. 7 is an explanatory view showing the action of the electric field on the developer in the developing area, and FIG. 2 is a schematic configuration diagram showing an example of an image recording apparatus using the developing device of FIG.

1 to 5, reference numeral 1 denotes a drum-shaped or belt-shaped image forming body which has a photoconductive layer on a grounded conductive substrate and rotates in the direction of the arrow during image formation. An electrostatic image having a dot structure is formed by being charged by the charging device shown and being incident on the image exposure by the laser beam scanner. 2 is a developing device frame, 3 is a developer pool, and the developer pool 3 is charged with the same polarity as that of the image forming body 1, preferably having an average particle size of 10 μm or less, particularly preferably having an average particle size of 1 to 7 μm. A one-component developer containing mainly non-magnetic toner particles, containing a fluidizing agent for improving the flow slippage of the toner particles as necessary, and a cleaning agent for facilitating cleaning of the image forming surface, etc. To be

When the average particle diameter of the toner particles exceeds 10 μm, the reproducibility of delicate lines, points or density difference decreases, and when it is less than 1 μm, the particles easily scatter and fog or stains inside the machine easily occur. Become. Further, the non-magnetic toner particles are preferable in terms of color vividness and the fact that a magnet body is not required for the developer carrying body. Toner particles are conventionally known by a pulverization method,
Those obtained by a method such as suspension polymerization method and emulsion polymerization method can be used.
A material having a charge amount of μC / g is preferable in terms of the transportability and the developability by the developer transporting body.

The charge amount of the toner particles is such that the developing device is driven without forming an oscillating electric field in the developing area, and the developer layer carried to the developing area by the developer carrying body is removed from the developer carrying body by air. Hosokawa Micron Co., Ltd. charge amount measuring device "E-
It is the value measured by dropping it on the "Spart Analyzer".
If the developing device is not driven by its own motor, the developing device must be removed from the image recording device before separating the developer from the developer transport body. For example, the charge amount can be measured by performing the above-mentioned driving with the developing device removed from the image recording device.

As a fluidizing agent for imparting fluidity to toner particles, silicon oxide, aluminum oxide, titanium oxide, zinc oxide, zirconia oxide, chromium oxide, cerium oxide, tungsten oxide, antimony oxide, copper oxide,
Oxides of tin oxide, tellurium oxide, manganese oxide, boron oxide, barium titanate, aluminum titanate, magnesium titanate, calcium titanate, strontium titanate, etc., silicon carbide, tungsten carbide, boron carbide, titanium carbide Carbides such as silicon nitride, titanium nitride,
Inorganic fine particles made of nitride such as boron nitride, fine particles obtained by hydrophobizing these fine particles, acrylic resin, styrene resin, styrene-acrylic copolymer resin, fluorine resin, silicone resin, olefin polymer It is possible to use a mixture of a plurality of organic fine particles composed of an olefin copolymer resin or a mixture of a plurality of inorganic fine particles or organic fine particles. The fluidizing agent preferably has an average particle size of 0.005 to 0.1 μm and an addition amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the toner particles in view of the effect on the toner particles, the dispersibility, and the effect on the image.

The average particle size of the fluidizing agent is the enlarged image of the charging aid obtained by using a scanning electron microscope (magnification: 5000).
Image analysis device "SPICCA" (Nippon Avionics)
It is the number average particle diameter obtained by image analysis by inputting it into (manufactured by K.K.).

As the cleaning agent, a fatty acid metal salt,
A surface-active agent such as organic group-substituted silicon or fluorine is used.

Reference numeral 4 is made of a metal material such as aluminum, copper or stainless steel, and its surface is finished by roughening such as sandblasting to a rough surface of 1 to 5 μm according to JIS-B0610's 10-point average roughness. , The minimum gap with the image forming body 1 is set in the range of 0.2 to 1.0 mm, and the developer carrier 5 which rotates in the arrow direction at the time of development also rotates in the arrow direction and the one-component development of the developer pool 3 Similarly, stirring means 6 for stirring the developer, 6 also rotates in the direction of the arrow to stir the developer in the developer reservoir 3 by the fur brush and supplies it to the surface of the developer transport body 4, and 7 denotes the developer transport body. 4 is a developer amount regulating member made of an insulating elastic material such as a rubber sheet that elastically abuts the surface of the developer carrier 4 to form a thin developer layer on the surface of the developer carrier 4. The quantity regulating member 7 is bent in a U shape. The end developing device frame 2 supporting section 2
The developer amount regulating member 7 illustrated in FIGS. 3 and 5 is cantilevered on the developing device frame 2 and is fixed to A. The U-shaped curved surface regulates the layer thickness of the developer layer. The surface of the developer layer is supported on the side of the free end to regulate the layer thickness of the developer layer.

Reference numeral 8 denotes a linear electrode which is arranged in a gap where the developer transport body 4 is close to the image forming body 1 and extends in a direction perpendicular to the transport direction of the developer layer. In the linear electrodes 8 illustrated in FIGS. 1 and 2, the tip ends of the tension springs 9 provided at both ends are fixed to the fixing pins 2B that are planted on the outer surfaces of both side plates of the developing device frame 2. It is installed, and the disposition position is regulated by the front end surfaces of the development areas of both side plates of the developing device frame 2 and the positioning pins 2C implanted in both side plates.

The linear electrode 8 is disposed at the center where the upstream side is + and the downstream side is − from the position where the developer transport direction is closest to the image forming body 1 of the developer transport body 4. The angle θ is preferably in the range of −10 to + 15 °, particularly −5 to + 10 ° in order to efficiently cloud the developer and supply it to the developing zone without causing scattering of the developer in the machine, Further, it is necessary that the position in the developing area gap direction does not come into contact with the toner image on the image forming body 1 so as not to disturb the toner image, and it is preferable not to come into contact with the surface of the developer transport body 4 from the viewpoint of durability and the like. .
For this purpose, it is preferable that the outer diameter d of the linear electrode 8 is 0.1 g or more and 0.5 g or less, where g is the minimum gap in the developing area. It is preferable g when toner particles are ejected from a developer layer which is not in contact with the image forming body 1 to develop an electrostatic image.
Is about 0.2 to 1.0 mm, the durability of the linear electrode 8 is deteriorated when d is smaller than 0.1 g, and the developer layer passes the position of the linear electrode 8 when d is larger than 0.5 g. This is because it becomes easy to contact the surface of the image forming body 1 during the process.
For example, when the linear electrode 8 has a surface layer of an insulating resin, the diameter of the conductive core wire is in the range of 50 to 150 μm, the thickness of the insulating surface layer is in the range of 20 to 50 μm, and the outer diameter is 100 to 200 μm.
It is preferable to use one having a range of. The linear electrode 8 having an insulating surface layer is used when the developing device frame 2 is made of a conductive material such as metal in the example of FIGS. 1 and 2 or when the linear electrode 8 contacts the surface of the developer transport body 4. Used.

Reference numeral 11 in FIG. 2 denotes a spacer roller which is rotatably provided coaxially with the developer transport body 4 and which is brought into contact with both sides of the image forming body 1 outside the image forming surface to form an image with the developer transport body 4. Body 1
Regulate the gap. Reference numeral 12 is a cleaning blade that reduces the developer on the developer transport body 4 that has passed through the developing area to the developer reservoir 3.

3 to 5 show another method of disposing the linear electrodes 8. One end of the linear electrode 8 is supported by the developing device frame 2 in a cantilever manner, and the tip of the insulating plate member 10 elastically abutting or adjoining the developer transport body 4 on the other free end side. By being fixed to the surface, the developer transport body 4
It is held in a non-contact state at a certain distance from the surface of the. Since the linear electrode 8 is held by the insulating plate member 10, not only can the durability of the linear electrode 8 be improved and the linear electrode 8 can be more accurately arranged, but also the line when forming an oscillating electric field can be formed. It is possible to suppress the vibration of the striped electrode 8 and prevent uneven density and horizontal stripes on the image. In order to improve the setting accuracy of the linear electrode 8, the insulating plate-shaped member 10 is preferably brought into contact with the developer transport body 4. At that time, as shown in FIG.
Elastic member 10A made of urethane rubber, silicone rubber, etc.
It is desirable to attach or apply the toner in order to prevent the developer layer from being disturbed. As the insulating plate-shaped member 10, polyimide,
A general insulating resin plate such as polycarbonate or polyester can be used.

In the developing device as described above, the surface of the image forming body 1 is charged to a positive or negative potential H _D [V], and the charged surface is irradiated with image exposure of a laser beam to generate a potential L.
_{In the} case of performing reversal development in which an electrostatic image composed of the distribution of the low potential spots having been discharged to _D [V] is formed and the toner particles charged with the same polarity are attached to the low potential spots, the linear electrodes 8 are the same. applying a bias voltage having a polarity at a potential L _D [V] is greater than the DC component voltage G _D [V], 2G _D is the developer conveying member 4 in the same polarity, less than preferably 1.5G _D (2 / 3) G _D, preferably applies a bias voltage consisting of a large DC component voltage and an AC component voltage than 0.7 G _D. As a result, the developer is prevented from accumulating on the linear electrode 8, and as shown in FIG. 7, the linear electrode 8 can stably and efficiently supply the clouded developer to the developing area. It is possible to stably carry out reversal development with a sufficient density.

Although an AC component may be superimposed on the bias voltage applied to the linear electrode 8, the AC component has the same phase as the AC component of the bias voltage of the developer carrier 4 and has a small amplitude. It is necessary to prevent the occurrence of spark discharge, developer scattering or fogging.
Further, if the bias voltage of the linear electrode 8 and the DC component of the bias voltage of the developer carrier are made the same, the bias power source of the linear electrode 8 is replaced with the bias power source of the developer carrier 4 as in the example of FIG. It can be shared, and the power supply device can be simplified and the cost can be reduced. In any of the examples, the linear electrode 8 is stretched to a length extending to the outside of the developer carrying width,
It is preferable to apply the bias voltage to the linear electrode 8 in the portion extending to the outside in order to uniformly form the cloud over the entire conveying width of the developer.

1 and 3 show examples in which the bias power source of the developer transport body 4 and the bias power source of the linear electrode 8 are independent, and FIG. 5 shows the DC component of the bias voltage of the developer transport body 4 and the line. An example is shown in which the bias power source of the linear electrode 8 having the same bias voltage as the linear electrode 8 is common to the bias power source of the developer transport body 4. R1 and R2 are protection resistors, E1 and E3 are DC power supplies, and E2 is an AC power supply.

For example, the surface of the OPC photosensitive layer of the image forming body 1 is charged to −800 V, and an electrostatic image composed of a distribution of low potential spots of about −100 V is formed on the surface by incidence of a laser beam. The minimum gap in the development area is 0.2-
At a thickness of 1.0 mm, the developer amount control member 7 or the insulating plate member 10 on the developer transport body 4 charges the layer to a thickness of − (2 to 30) μC / g which does not contact the surface of the image forming body 1. When a developer layer mainly composed of toner particles is formed for development, a DC voltage of-(600 to 750) V and a bias voltage obtained by weighting the AC voltage in the range shown in white in FIG. 6 are applied to the developer carrier 4. An oscillating electric field is formed in the developing area by applying it to the linear electrode 8-(300 to 1125)
It is preferable to apply a DC voltage of V, preferably-(420 to 975) V.

As a result, a strong oscillating electric field is generated in the vibrating region between the developer transport body 4 and the linear electrode 8 as shown in FIG. Efficiently cloud the developer, and the clouded developer is stably guided to the developer area. Therefore, in the development area, the toner cloud stably develops a toner image of sufficient density without fogging the electrostatic image. can do.

Further, in the example of FIG. 5, the photoconductor layer of the image forming body 1 is charged to −800 V, and the surface thereof is subjected to image exposure by the laser beam exposure device. Is formed, the minimum gap in the developing area is 0.2 to 1.0 mm, and the developer amount regulating member 7 does not contact the surface of the image forming body 1 on the developer transporting body 4-(2 3
0) When a developer layer composed mainly of toner particles charged to μC / g is formed and developed, a DC voltage of − (150 to 300) V is applied to the developer transport body 4 and a range of the white range in FIG. It is preferable to apply a bias voltage on which an AC voltage is superimposed, and the same bias voltage as the DC component of the bias voltage of the developer carrier 4 is applied to the linear electrode 8. As a result, similarly to the case described above, it is possible to stably perform development with a sufficient density without fogging with a simpler power supply device.

In FIG. 6, the range shaded by the horizontal lines is the range where fogging is likely to occur, the range shaded by the vertical lines is the range where dielectric breakdown is likely to occur, and the range shaded by the diagonal lines is the deterioration of image quality. It is a range that is likely to occur, and a range without shade is a preferable range where a stable and clear image can be obtained. As is clear from the figure, the range in which fogging is likely to occur changes with changes in the AC voltage component. The waveform of the AC voltage component is
Not limited to a sine wave, a rectangular wave or a triangular wave may be used. Further, the low frequency region shaded with dots in the figure is a range where uneven development occurs due to the low frequency.

Finally, an example in which a color image is recorded by a color image recording apparatus using the developing device of the present invention will be described.

The developing device is as shown in FIG. 3, and the developer transport body 4 is made of aluminum whose surface with an outer diameter of 15 mm is finished to a rough surface of 1 to 5 μm according to JIS-B0610 rough surface display. When developing, the image forming body 1 rotates at a substantially constant speed in the arrow direction during development. The gap between the developer transport body 4 and the developing area of the image forming body 1 is 10
Set to 00 μm. The developer amount regulating member 7 is made of urethane rubber having a thickness of 2 mm, and forms a developer layer having a thickness of 0.1 mm on the surface of the developer transport body 4. The linear electrode 8 has a diameter of tungsten
An elastic member made of a 100 μm wire and made of a silicone rubber layer having a thickness of 100 μm and provided on the surface so that the position of the wire is θ and the center is 300 μm away from the surface of the developer transport body 4. It is supported by a front end surface of an insulating plate member 10 made of a polyester sheet having a thickness of 1 mm, which is in contact with the surface of the developer carrier 4 by 10A.

In the developer pool 3, 100 parts by weight of styrene-acrylic resin, 10 parts by weight of color pigment, and 0.4 parts by weight of a charge control agent for negative charging were obtained by a suspension polymerization method having a weight average particle diameter of 5.3 μm. A one-component developer was added to 100 parts by weight of the non-magnetic toner particles, and 2 parts by weight of a fluidizing agent made of titanium oxide having a number average particle diameter of 0.02 μm, which was hydrophobized with hexylsilane. The charge amount of the developer layer formed on the developer transport body 4 of this one-component developer is -7.5.
It was μC / g. This charge amount is a value measured by the charge amount measuring device "E-Spurt Analyzer" manufactured by Hosokawa Micron Corporation as described above.

During development, a bias voltage consisting of a superposition of a DC voltage of -700 V and an AC voltage of 1 KHz and a peak-to-peak voltage of 1000 V is applied to the developer carrier 4 and the linear electrode 8 is -600 V.
DC voltage is applied.

In the image recording apparatus, as shown in FIG. 8, the image forming body 1 has a belt shape and has an OPC photosensitive member surface layer, and an electrostatic image forming means and yellow, magenta, cyan and black toner particles are provided around them. 4 of the above-mentioned developing devices using
24 is provided, and a color image is formed on the image forming body 1 by repeating the formation of the electrostatic image by the electrostatic image forming means and the reversal development by the corresponding developing device for each rotation of the image forming body 1. And In the recording device of FIG. 8, 13 is a cleaning device, 14 is a charger, 15 is a laser beam scanner, 16 is a transfer device, 17 is a heat roller fixing device, 18 is a paper feed cassette, 19 is a paper feed roller, and 20 is a registration device. It's Laura. The image forming body 1 rotates in the direction of the arrow at a surface speed of 180 mm / sec, and the surface of the image forming body 1 is reduced by the charger 14.
It is charged to 800 V, and image exposure is made incident on the surface of the laser beam scanner 15 to form an electrostatic image in which a low potential spot having a potential of about -100 V is distributed. This electrostatic image is developed by the developing device under the above-mentioned conditions, and the formed color image is transferred to plain paper and fixed at a fixing temperature of 140 ° C.

As described above, 50,000 color image recording sheets were obtained. As a result, a clear color image having high image density and no fog can be stably recorded from the beginning to the end, and almost no stain inside the color image recording apparatus occurs.

In the same developing device, the direct voltage applied to the linear electrode 8 and the developer carrier 4 was supplied from a common power source, and even if the voltage was set to -700 V, a good color image recording paper was obtained with 50,000. I was able to get one.

On the other hand, when the DC voltage applied to the developer transport body 4 is -700 V and the DC voltage applied to the linear electrode 8 is -500 V, the other color previously developed on the linear electrode 8 is used. The toner flows back and is mixed into the developing device. Similarly, when −250 V was applied to the linear electrode 8, toner was deposited on the electrode, resulting in poor development and fouling inside the machine. Further, when -1300 V was applied to the linear electrode 8, no toner cloud was generated and the development was defective.

[0040]

According to the developing device of the present invention, the developer is efficiently clouded by the linear electrode and supplied to the developing region without causing the deposition of the developer on the linear electrode in the gap of the developing region. There is a remarkable effect that it is possible to stably carry out development of a sufficient density without any trouble.

[Brief description of drawings]

FIG. 1 is a partial configuration diagram of an image recording apparatus showing an example of a developing apparatus of the present invention.

FIG. 2 is a view showing an arrow XX in FIG.

FIG. 3 is a partial configuration diagram of an image recording apparatus showing another example of the developing device of the present invention.

FIG. 4 is a partial configuration diagram of an image recording device showing another example of the developing device of the present invention.

FIG. 5 is a partial configuration diagram of an image recording device showing another example of the developing device of the present invention.

FIG. 6 is a graph showing an example of an AC component of a bias voltage of the developer transport body.

FIG. 7 is an explanatory diagram showing an action of an electric field on a developer in a developing area.

FIG. 8 is a schematic configuration diagram showing an example of an image recording apparatus using the developing device of the present invention.

[Explanation of symbols]

 1 Image Forming Body 2 Developing Device Frame 3 Developer Reservoir 4 Developer Conveying Body 5 Stirring Means 6 Stirring Supplying Means 7 Developer Amount Controlling Member 8 Linear Electrode 9 Tension Spring 10 Insulating Plate Member 11 Spacer Roller 12 Cleaning Blade

Claims (3)

[Claims] 1. A developer transporting body, which is composed mainly of toner particles and which does not contact the surface of the image forming body of the developer, is formed on the surface of the developer transporting body, and the developer transporting body is arranged in a gap facing the image forming body. A linear electrode extending in a direction perpendicular to the transport direction, a main bias power source for applying a bias voltage having a DC component and an AC component having the same polarity as the charging of the image forming surface to the developer transport member, and a linear electrode The electrode is provided with a sub-bias power source for applying a bias voltage having a DC component of at least the same polarity as the charging of the surface of the image forming body. In a developing device that causes toner particles to fly from the developer layer and adhere to the electrostatic latent image on the surface of the image forming body, the DC component absolute value S _D [V] of the bias voltage of the developer carrier and the bias voltage of the linear electrode DC component absolute value G _D [V], the potential absolute value L _D of static eliminator incident image exposure to the charged surface of the image forming body (V) satisfies the relation of 0.5S _D <G _D <1.5S _D and L _D <G _D The developing device is characterized in that the toner particles charged with the same polarity as that of the image forming body are attached to the charge eliminating portion of the image forming body. 2. A developer transporting body, which is composed mainly of toner particles and which does not come into contact with the surface of the image forming body of the developer, is formed on the surface of the developer transporting body, and the developer transporting body faces the image forming body. A linear electrode extending in a direction perpendicular to the transport direction, a main bias power source for applying a bias voltage having a DC component and an AC component having the same polarity as the charging of the image forming surface to the developer transport member, and a linear electrode The electrode is provided with a sub-bias power source that applies a DC bias voltage having the same polarity as the charging of the image forming body surface, and a bias voltage is applied to each of the developer conveying body and the linear electrode to form an image from the developer layer on the developer conveying body surface. In a developing device in which toner particles charged with the same polarity as the charge on the surface of the forming body are made to fly and adhere to the electrostatic latent image on the surface of the image forming body, the DC component power source part of the main bias power source is common to the sub bias power source. Characteristic present Image device. 3. The developing device according to claim 1, wherein the linear electrode is supported by an insulating plate member that is in contact with or close to the developer transport body.