JPH06250509A - Developing device - Google Patents

Abstract

PURPOSE:To provide a developing device using an elastic blade, which can be adjusted so that most of toner particle lumps by agglutination can be decomposed since a layer thickness of a developing layer becomes uniform in the width direction of the device, and by which a change in a pressure contact condition of the elastic blade is small even if a developer carrying body has an insulating surface layer and a uniform and thin developing layer can be formed on the surface of the developer carrying body, and a developing device by which a developer is not accumulated on a line shape electrode even if the line shape electrode is used to transform the developer into a cloud or to control soaring and transformation of the developer into a cloud in a developing area and soaring control can be carried out stably and efficiently. CONSTITUTION:A developing layer is formed on the surface of a developer carrying body 4 when a developer passes through a contact part of a plate-like elastic body 7 arranged so that an intermediate part can come into contact with the surface of the developer carrying body while fixing both ends. A line shape control electrode 8 vibrated by rotation of the developer carrying body while coming into contact in an electrically insulating condition with the surface of the developer carrying body 4, is arranged on the downstream side within a range of 1-15 deg. from a position where the developer carrying body 4 in a developing area comes closest to an image carrier 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an electrophotographic recording device and the like, and in particular, a developer layer mainly composed of toner particles which does not rub the image carrier surface is formed on the developer carrier surface. The present invention relates to a developing device in which a developer is caused to fly under an oscillating electric field in a developing area and adheres to an electrostatic image on the surface of an image carrier.

[0002]

2. Description of the Related Art In the developing device as described above, the toner concentration of the developer is substantially constant, so that the means for replenishing the developer is simple, and the developer layer on the surface of the developer carrier slides on the surface of the image carrier. Since no rubbing occurs on the image because it is not rubbed, it is possible to easily prevent the occurrence of fogging. However, in order to prevent fogging and to achieve sufficient density development, the gap in the development area should be set small so that the electric field generated by the electrostatic image on the image carrier surface acts strongly on the developer on the developer carrier surface. Therefore, it is required to form the developer layer thinly and uniformly on the surface of the developer carrier. It is also important to efficiently cloud the developer layer conveyed to the development area so that it can easily participate in development.

As a method of forming a developer layer on the surface of a developer carrier, it is difficult to form a thin and uniform developer layer by a method of facing a doctor blade with a gap on the surface of the developer carrier.

Therefore, one end side of the elastic blade is fixed and the blade surface is brought into pressure contact with the surface of the developer carrying member on the upstream side of the developing area, and the developer passes through the pressure contact portion to form a thin developer layer. The developing device is known from Japanese Patent Publication No. 63-16736 and US Pat. Nos. 4,458,627 and 4,473,627.

However, in the above-mentioned method of abutting the elastic blade having one end fixed, the pressing force of the elastic blade is different between the central portion and the end portion in the width direction of the device, which tends to cause a difference in layer thickness. The elastic blade gradually rolls up during use, so that the pressing force easily changes with time, and therefore the layer thickness easily changes with time. , The elastic blade is easily pushed up to allow them to pass through as they are, and at that time the layer thickness variation of the developing layer becomes large, and the developer conveying body has a large surface friction resistance such as having an insulating surface layer. In such a case, vibration easily occurs in the pressed state of the elastic blade, which causes a problem that the layer thickness variation becomes large.

Further, in order to cloud the developer in the developing area and to control the flight of the developer, the toner image and the developer layer formed on the image carrier and the developer carrier are prevented from coming into contact with each other. There is known a developing device in which a linear electrode is disposed on the linear electrode, and a DC voltage or a voltage having an AC component is applied to the linear electrode.

However, in the above-described developing device, the developer is deposited on the linear electrode to change the action of the linear electrode, or the deposited developer contacts the toner image or the developer layer to disturb the toner image. However, there are problems that the developer layer is not uniform, the deposited developer is peeled off, and the inside of the machine is contaminated.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems of the conventional developing device, and the pressing force of the elastic blade against the developer transport body is controlled by the layer of the developer layer. The thickness can be adjusted to be uniform in the width direction of the apparatus, and most of the toner particle agglomerates due to aggregation can be separated. The first object of the present invention is to provide a developing device using an elastic blade capable of forming a uniform thin developer layer on the surface of a developer transport body with a small fluctuation in the pressure contact state of the elastic blade even with an insulating surface layer. The linear electrode is used for cloud formation and flight control of the developer, and the developer is not deposited on the linear electrode. Therefore, the cloud formation of the developer in the development area and the flight control can be stably performed. Proposal of developing device that can be performed well The a second object.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a developer layer mainly composed of toner particles that does not rub the surface of an image carrier is formed on the surface of a developer carrier, and the developer is developed under an oscillating electric field in the developing area. In a developing device for flying and adhering to the electrostatic image on the surface of the image carrier, the contact of the plate-like elastic body provided so that the layer of the developer is fixed at both ends and the middle is brought into contact with the surface of the developer carrier. The first object is achieved by the configuration of the developing device, which is characterized in that the developer passes through the section.
A layer of a developer mainly composed of toner particles that does not rub against the surface of the image carrier is formed on the surface of the developer carrier, and the developer is caused to fly under an oscillating electric field in the developing area and adhered to the electrostatic image on the surface of the image carrier. In the developing device, the developer carrier in the developing zone is electrically insulated from the surface of the developer carrier without contacting the surface of the image carrier on the downstream side within a range of 1 to 15 ° from the position closest to the image carrier. The structure of the developing device, which is provided with a linear control electrode that is abutted by the above and is vibrated by the rotation of the developer transport body,
Alternatively, a layer of a developer mainly composed of toner particles that does not rub the surface of the image carrier is formed on the surface of the developer carrier, and the developer is caused to fly under an oscillating electric field in the developing area to form an electrostatic image on the surface of the image carrier. In the developing device to be attached, the linear control electrode is provided so as to be capable of vibrating in the gap direction of the developing area in a range where the linear control electrode abuts the surface of the developer carrier in an electrically insulating state and does not contact the surface of the image carrier in the developing area. The second object is achieved by the structure of the developing device.

[0010]

In the developing device in which both ends of the plate-like elastic body are fixed so that the middle is in contact with the surface of the developer carrying body, fixing the both ends of the plate-like elastic body only prevents the plate-like elastic body from curling up during use. Instead, make the intermediate contact part a convex curved surface toward the developer transport body side where the repulsive force becomes large, and further adjust the curvature of the curved surface so that the layer thickness of the developer layer becomes uniform in the device width direction. Therefore, it is possible to stably form a uniform developer layer having a small layer thickness on the surface of the developer carrier not only having the insulating surface layer but also having the insulating surface layer. Most of the particle lumps and the like can be decomposed at the contact portion of the plate-like elastic body.

Further, the linear control electrode, which is vibrated by the rotation of the developer carrier or the oscillating electric field in the developing region or the action of the vibrator, is provided in the developing region so as to come into contact with the surface of the developer carrier in an electrically insulated state. In the device,
Since the linear control electrode vibrates to prevent the developer from accumulating, and because it contacts the surface of the developer transport body, the distance between the developer layer on the surface of the developer transport body and the impact of the vibration on the surface of the developer transport body is very short. A strong oscillating electric field is applied during that time to efficiently cloud the developer in the developing area. Therefore, even if the developer layer formed on the surface of the developer transport body is a thin layer, the electrostatic image can be developed at a sufficient development density and without fog.

[0012]

The present invention will be described below with reference to the illustrated examples.

FIG. 1 is a partial sectional view of an image recording apparatus showing an example of a developing apparatus of the present invention, and FIGS. 2 to 4 are partial sectional views of a developing apparatus showing another example of a plate-like elastic body, FIG. 5 and FIG. FIG. 7 is a partial plan view showing the example in which the curvature of the contact portion of the plate-like elastic body in the device width direction is changed, as seen from the plate-like elastic body fixed side to the developer conveying body side, and FIGS. 7 is a view taken along the line XX in FIG. 7, FIG. 9 is a partial sectional view of the developing device showing a stretched state of the linear control electrode vibrated by the rotation of the developer transport body, and FIG. FIG. 11 is a partial side view of the developing device showing a stretched state of a linear control electrode that is vibrated, FIG. 11 is a front view of FIG. 10 seen from the right side, and FIG. 13 is a partial cross-sectional view of a developing device showing another example, FIG. 13 is an example of an image recording device using the developing device of the present invention. It is a schematic block diagram showing.

In FIG. 1, reference numeral 1 denotes a drum-shaped or belt-shaped image bearing member 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 in response to the charging by the apparatus and the incidence of the image exposure by the laser beam scanner. 2 is a developing device frame, 3 is a developer reservoir, and the developer reservoir 3 is charged with the same polarity as that of the image carrier 1 is charged, preferably having an average particle diameter of 10 μm or less, particularly preferably 1 to 7
A charging aid mainly composed of non-magnetic toner particles of μm, which promotes charging of the toner particles as needed, a fluidizing agent for improving flow sliding of the toner particles, a cleaning agent for facilitating cleaning of the image carrier surface, and the like. A one-component developer containing a small amount of is stored.

When the average particle diameter of the toner particles exceeds 10 μm, the reproducibility of delicate lines, points or density difference deteriorates, and when it is less than 1 μm, the toner tends to 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. As the toner particles, those selected from conventionally known ones can be used, and those having a charge amount of 2 to 30 μC / g when supplied to the developing area are in terms of the transportability and the developability by the developer transporter. preferable.

The charging amount 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 blown from the developer carrying body by Hosokawa Micron. It is a value measured by dropping it on a charge amount measuring device “E-Spurt 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.

The charging aid is used for the above-mentioned toner particles having a small charge amount, and includes silicon oxide, aluminum oxide,
Titanium oxide, zinc oxide, zirconia oxide, chromium oxide,
Cerium oxide, tungsten oxide, antimony oxide, copper oxide, tin oxide, tellurium oxide, manganese oxide, boron oxide, barium titanate, aluminum titanate, magnesium titanate, calcium titanate, strontium titanate and other oxides, carbonization Silicon, tungsten carbide,
Inorganic fine particles composed of carbides such as boron carbide and titanium carbide, nitrides such as silicon nitride, titanium nitride and boron nitride, fine particles obtained by subjecting these fine particles to hydrophobic treatment, acrylic resin, styrene resin, styrene-acrylic Organic fine particles composed of a system copolymer resin, a fluorine resin, a silicone resin, an olefin polymer, an olefin copolymer resin, or mixed fine particles of these inorganic fine particles and organic fine particles can be used as a charging aid. From the viewpoint of the effect on the toner particles, the dispersibility, and the adverse effect on the image, the charging aid is preferably in the range of 0.01 to 0.1 μm in average particle size and in the range of 0.2 to 5 parts by weight based on 100 parts by weight of the toner particles.

The average particle size of the charging aid 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 fluidizing agent, colloidal silica, hydrophobic titania, silicon varnish, metal soap or nonionic surface active agent is used, and as the cleaning agent, fatty acid metal salt, organic group-substituted silicon or fluorine surface active agent. Agents are used.

Reference numeral 4 is made of a metal material such as aluminum, copper or stainless steel, and the surface is finished to a rough surface of 2 to 10 μm according to JIS-B0610's 10-point average roughness by rough surface processing such as sandblasting. , The minimum gap with the image carrier 1 is set in the range of 0.2 to 1.0 mm, and the developer carrier 5 which rotates in the direction of the arrow at the time of development also rotates in the direction of the arrow, and the developer pool 3 for one-component development Similarly, a stirring means for stirring the developer, 6 also rotates in the direction of the arrow to stir the one-component developer in the developer pool 3 by the fur brush and supplies it to the surface of the developer transport body 4, and 7 denotes a developer. Both ends of the carrier 4 are fixed by fixing portions 2A provided on the developing device frame 2 on the upstream side of the developing area facing the image carrier 1, and the middle part is curved to the developer carrier 4 side. Touch the middle curved surface to the surface of the developer transport body 4. It is a plate-like elastic body made of rubber or the like, and the developer attached to the surface of the developer carrying body 4 and carried is passed through the abutting portion of the plate-like elastic body 7 to form a thin and uniform developer layer. Form.

The plate-like elastic body 7 has a rubber hardness of 50 according to JIS.
Made of an elastic material of more than 80 ° and more than 80 °, and fixed at both ends to form a curved surface with a radius of curvature of 1.1t or more and 7t or less by fixing both ends, and develop with the curvature of the curved surface almost unchanged. The one that contacts the surface of the agent carrier 4 is preferable,
In particular, it is preferable that the radius of curvature of the curved surface is in the range of 1.2t or more and 5t or less. When the rubber hardness is softer than 50 °, it becomes difficult to uniformly form a thin developer layer, and when it is harder than 80 °, the surface of the developer transport body 4 is easily scratched, and a preferable radius of curvature is It becomes difficult to form a curved surface. When the radius of curvature is smaller than 1.1t, one end side of the plate-like elastic body having a thickness of 2t is fixed and the free end portion is brought into contact with the surface of the developer transport body 4, which is similar to
The same problem as in the conventional elastic blade occurs, and when the radius of curvature exceeds 7 t, the elastic repulsion force when forming the developer layer is weak and it is difficult to form a uniform thin layer. Become.

The fixing method for the both ends of the plate-like elastic body 7 is as shown in FIG.
However, the method shown in FIGS. 2 to 4 may be used. Further, when the fixed distance between both ends is constant in the device width direction, the repulsive force of the contact portion of the plate-like elastic body 7 in the device width direction becomes weaker than the central portion on both end sides, and the layer thickness of the developer layer is reduced. It tends to be thick and uneven. In order to improve that point, as shown in FIGS. 5 and 6, the distance between the fixing portions 2A fixing both end sides of the plate-like elastic body 7 is made narrower on both end sides than the central portion in the device width direction. Therefore, the radius of curvature of the abutting portion is changed to be smaller on both end sides than the central portion to make the abutting portion repulsive force uniform in the device width direction, whereby a thin developer layer that is uniform in the device width direction is obtained. It can be tailored to be formed.

Further, as described above, in order to adjust the radius of curvature of the abutting portion of the plate-like elastic body 7 in the device width direction, as shown in FIGS. 7 and 8, the fixing portion 2A is moved in the device width direction. If the fixing intervals on both sides of the plate-like elastic body 7 can be adjusted by the adjusting screws 25 provided at appropriate intervals, the radius of curvature of the abutting portion can be adjusted appropriately according to the fluidity and charging property of the developer. be able to. Reference numeral 7A in FIGS. 7 and 8 is a plate-like elastic body 7.
The reinforcing thin plates for each screw provided on both end sides of the plate-like elastic member 7 have a length extending over the entire width of the plate-like elastic body 7 in the illustrated example, but may be provided only at a portion where the adjusting screw 25 abuts.

Numeral 8 is a developing zone in which θ is within the range of 1 to 15 ° on the downstream side of the position where the developer transport body 4 is closest to the image carrier 1, and the developer transport body 4 is substantially aligned with its axis. 9 is a linear control electrode that abuts in parallel over the entire width and is given a circumferential vibration by the rotation of the developer transport body 4 in the direction of the arrow.
As shown in FIG. 3, the portions of the developer transport body 4 that extend outward from both ends are bent to the outside of both side walls of the apparatus frame 2, and both ends are fixed to the fixing pins 2B on both side walls via the tension springs 9. The position of the positioning pin 2 on both side walls is slidable in the longitudinal direction at the portion bent to the outside of both side walls of the device frame 2.
By being defined by C, the rotation of the developer transport body 4 causes the surface of the developer transport body 4 to vibrate in the circumferential direction within the range of 1 to 15 °. By this vibration, the accumulation of the developer on the control electrode 8 is prevented, the operation of the control electrode 8 becomes stable and efficient, and the clouding of the developer is promoted.
Reference numeral 10 in FIG. 9 or FIGS. 10 to 12 is an abutting roller against the image carrier 1 that regulates the gap in the developing area.

Although the control electrode 8 in the illustrated example is covered with an insulating surface layer, an insulating layer may be provided on the surface of the developer carrier 4 so that the control electrode 8 does not have an insulating surface layer. However, in that case, needless to say, electrical insulation from the device frame 2 should be taken into consideration so that a bias voltage can be applied to the control electrode 8. Further, almost the same result can be obtained even if the tension spring is omitted at one end of the control electrode 8.

In any case, the control electrode 8 has an outer diameter d,
When the minimum gap in the developing area is g, d is preferably 0.1 g or more and 0.5 g or less. That is, when the toner particles are made to fly from the developer layer which is not in contact with the image carrier 1 to develop the electrostatic image, the preferable g is about 0.2 to 1.0 mm.
If it is less than 0.1 g, the durability of the control electrode 8 will be poor, and if it is more than 0.5 g, the developer layer will have a poor control electrode 8.
This is because it becomes easy to contact the surface of the image carrier 1 when passing through the position. For example, when the control electrode 8 has a surface coated with an insulating resin, the diameter of the conductive core wire is 50 to 15
It is preferable to use an insulating coating layer having a thickness of 25 to 50 μm and an outer diameter of 100 to 200 μm in a range of 0 μm.

The image carrier 1 has a surface of the OPC photosensitive layer of −80.
An electrostatic image composed of a distribution of low potential spots, which are charged to 0 V and become almost OV by the incidence of a laser beam on the surface thereof, is formed, and the minimum gap in the developing area is 0.2 to 1.0 mm. A developer layer mainly composed of toner particles having a layer thickness of − (2 to 30) μC / g which is not in contact with the surface of the image carrier 1 is formed on the upper surface of the developer carrier 4 by the above-mentioned elastic plate 7.
To the image carrier 1 by applying a bias voltage, which is a DC voltage of -700 V, an AC voltage of 0.5 to 5 KHz and a peak voltage of 0.5 to 3 KV, to form an oscillating electric field in the developing area.
-(400-800) on the control electrode 8 when developing the electrostatic image of
It is preferable to apply a DC voltage of V.

As a result, the developer carrier 4 and the control electrode 8
The strong oscillating electric field generated while the two approaches, combined with the vibration of the control electrode 8 described above, effectively cloud the developer,
Then, the oscillating electric field in the developing area and the electric field between the control electrode 8 and the image carrier 1 develop the electrostatic image by the toner cloud into a toner image of sufficient density without fogging.

However, when the position of the control electrode 8 is located downstream of the position where the developer carrier 4 is closest to the image carrier 1 and θ is 15 °, the developer is removed by the control electrode 8. Even if it is clouded, the amount of passing through the closest position is increased, and the effect of providing the control electrode 8 cannot be obtained, and a sufficient development density cannot be obtained. In addition, the control electrode 8
On the contrary, when the position θ is on the upstream side of the position where the above-mentioned θ is 1 °, the toner cloud is generated and diffuses more before entering the developing area, and the inside of the machine is contaminated due to the scattering of the developer. Easier to do. Further, depending on the structure of the developer layer forming means and the layer thickness regulating means, backflow of the toner cloud occurs, and the density of the toner cloud in the developing area decreases, and the developing density also decreases.

If a linear control electrode that vibrates in the gap in the developing area is used instead of the linear control electrode 8 that vibrates in the circumferential direction due to the rotation of the developer transport body 4, the control electrode Even if the position is wide from the above-mentioned range from the minimum gap position in the developing area to the position where θ on the upstream side is about 2 °, the same effect can be obtained, that is, sufficient developing density can be obtained without causing contamination in the machine. . 10 and 11 show a developing device using such a linear control electrode 81.

In FIGS. 10 and 11, a linear control electrode 81 covered with an insulating surface layer is stretched between one end sides of both arm portions 11A of the rocking frame 11. The rocking frame 11 has the other end portions of both side arm portions 11A connected to each other by a connecting beam portion 11B.
Since the shaft protrusion 11C provided in the central portion of 11A is engaged with the bearing holes provided on the outer surfaces of both side walls of the device frame 2,
From the position where the control electrode 81 contacts the surface of the developer transport body 4 to the position where the connecting beam portion 11B contacts the upper wall of the apparatus frame 2 and the control electrode 81 does not contact the surface of the image carrier 1. It is movable, and at the time of non-development, the connecting beam portion 11B comes to the position shown in the drawing in which the connecting beam portion 11B abuts the upper wall of the apparatus frame 2 by the urging of a coil spring (not shown). In this stationary state, the control electrode 81 is separated from the surface of the developer transport body 4, and the distance h between the center of the control electrode 81 and the surface of the developer transport body 4 is 0.
When 1 g ≦ h ≦ 0.5 g is satisfied, the control electrode 81 hardly vibrates due to the vibration of the rocking frame 11 in the above-described range, and the control electrode 81, the developer transport body 4, etc. It is preferable that the developer is prevented from accumulating on the control electrode 81 without being damaged, and the developer can be efficiently clouded by the action of the oscillating electric field between the developer transport body 4 and the control electrode 81.

The control electrode 81 of this example is unlikely to be rubbed by the developer transport body 4 unlike the control electrode 8 of the examples of FIGS. 1 and 9, so that the insulating coating layer is thinner. The durability that does not change can be obtained. Therefore, the diameter of the conductive core wire is in the range of 50 to 150 μm, and the thickness of the insulating coating layer is 20 to 50 μm.
It is preferable to use one having an outer diameter in the range of 100 to 200 μm in the range of μm.

In the developing device shown in FIGS. 10 and 11, as in the developing device shown in FIGS. 1 and 9, a voltage or a DC voltage having a polarity in which the DC voltage and the AC voltage are superposed on the developer carrier 4 and the control electrode 81 are changed. Is applied via a protective resistor. As a result, the control electrode 81 vibrates so as to impart the above-mentioned swing against the bias of the coil spring (not shown) to the swing frame 11 by the action of the oscillating electric field between the control electrode 81 and the developer transport body 4, and Prevents the accumulation of agents,
Moreover, since the developer is efficiently clouded, as described above, the electrostatic image of the image carrier 1 can be developed at a sufficient density without fogging even in the developing device of FIGS. it can.

FIG. 12 shows an example in which a linear control electrode 81 vibrating in the gap direction of the developing zone is stretched in the same manner as the control electrode 8 in FIG. 9, and the control electrode 81 in this example is also the developer transporting member 4. Due to the action of an oscillating electric field between the developer carrier 4 and the position where it abuts the surface of the developer carrier 4, it vibrates within a range where it does not contact the surface of the image carrier 1 to prevent the developer from accumulating and effectively cloud the developer. To do. In this example, the amplitude of the control electrode 81, particularly toward the image carrier 1, can be adjusted by changing the diameter, tension, etc. of the control electrode 81.

The control electrode 81 which vibrates in the gap direction of the developing zone does not necessarily have to abut on the surface of the developer transport body 4, but abutting it has a greater effect of preventing developer accumulation and clouding. Further, in the example of FIGS. 10 and 11, a vibrator may be separately provided and the swing frame 11 may be swung by the vibrator.

In any of the developing devices described above, the developer that has passed through the developing zone is the cleaning blade shown in FIG.
It is separated from the surface of the developer transport body 4 by 12 and is reduced to the developer pool 3.

Specific examples for carrying out the present invention will be shown below.

It is assumed that the developing device uses the control electrode 81 as shown in FIG. 1 except that the linear control electrode 81 vibrates in the gap direction of the developing region shown in FIG. The surface of the developer transport body 4 having an outer diameter of 15 mm is made of aluminum whose surface is roughened by JIS-B0610 to have a rough surface of 1 to 5 μm, and at the time of development, at substantially the same speed as the image carrier 1. Rotate. The gap between the developer transport body 4 and the developing area of the image carrier 1 is 1000 μm.
The plate-like elastic body 7 is made of urethane rubber having a thickness of 1 mm, and has both ends fixed by the fixing portions 2A of the device frame 2 and a radius of curvature of 3 in the middle.
A curved surface having a thickness of 0.1 mm is formed, and the curved surface is brought into contact with the surface of the developer transport body 4 to form a developer layer having a thickness of 0.1 mm on the surface.

The developer pool 3 has a weight average particle size of 5.3 parts consisting of 100 parts by weight of polyester resin and 10 parts by weight of color pigment.
Non-magnetic toner particles obtained by pulverizing and granulating method of μm 10
A one-component developer was used in which 2 parts by weight of a charging aid made of titanium oxide having a number average particle size of 0.1 μm, which was hydrophobized with hexylsilane, was added to 0 part by weight. This one
The charge amount of the developer layer formed on the developer transport body 4 of the component developer was −7.5 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.

The linear control electrode 81 has a diameter of a conductive core wire of 100.
μm, the thickness of the insulating coating layer is 30 μm, the outer diameter is 160 μm, and the center thereof is stretched at a position 300 μm away from the surface of the developer transport body 4 at a position where θ is 7 ° downstream from the minimum gap position of the developing zone. Then, it is assumed to vibrate with an amplitude of 100 μm. Then, at the time of development, the developer carrier 4 has a DC voltage of -700 V and 1 KH.
A bias voltage formed by superimposing an alternating voltage of z and a peak-to-peak voltage of 1000 V is applied, and the conductive core wire of the control electrode 81 is -600.
A DC voltage of V is applied.

In the image recording apparatus, as shown in FIG. 13, the image carrier 1 has a belt-like 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 the image carrier. 4 of the above-mentioned developing devices using
24 is provided, and a color image is formed on the image carrier 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 carrier 1. And In the recording apparatus of FIG. 13, 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 resist. It's Laura. The image carrier 1 rotates in the direction of the arrow at a surface speed of 180 mm / sec, and the surface of the image carrier 1 is reduced by the charger 14.
It is charged to 800 V, and image exposure is performed by the laser beam scanner 15 on its surface to form an electrostatic image in which low potential spots having a potential of almost 0 are 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.

The developing device is changed to one provided with a control electrode 81 as shown in FIGS. 10 and 11, and the control electrode 8 is provided on the surface of the developer carrier 4 as shown in FIGS. Change to one in which θ on the downstream side of the minimum gap position in the developing zone vibrates in the range of 3 to 10 °, and otherwise obtain the same conditions as above, and obtain 50,000 color image recording sheets. However, similar results were obtained in those cases.

Although the present invention has been described with reference to the example using the one-component developer, the present invention is not limited to these examples, and the present invention can be applied to the one using the two-component developer in which the magnetic carrier and the toner are mixed.

[0045]

As described above, according to the developing device of the present invention, a thin and uniform developer layer is formed on the surface of the developer carrier,
The developer layer can be efficiently clouded, an electrostatic image can be developed at a sufficient developing density without fogging, and a remarkable effect that the inside of the image recording apparatus is not contaminated can be obtained.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an image recording apparatus showing an example of a developing device of the present invention.

FIG. 2 is a partial cross-sectional view of a developing device showing another example of a plate-shaped elastic body.

FIG. 3 is a partial cross-sectional view of a developing device showing another example of a plate-shaped elastic body.

FIG. 4 is a partial cross-sectional view of a developing device showing another example of a plate-shaped elastic body.

FIG. 5 is a partial plan view showing an example in which the contact portion curvature of the plate-shaped elastic body in the apparatus width direction is changed and the developer transport body side is viewed from the plate-shaped elastic body fixed side.

FIG. 6 is a view on arrow XX in FIG.

FIG. 7 is a partial plan view of another example of changing the contact portion curvature of the plate-shaped elastic body in the device width direction, as viewed from the developer-conveying body side from the plate-shaped elastic body fixed side.

FIG. 8 is a view on arrow XX in FIG. 7.

FIG. 9 is a partial cross-sectional view of the developing device showing a stretched state of a linear control electrode vibrated by rotation of a developer transport body.

FIG. 10 is a partial side view of the developing device showing a stretched state of linear control electrodes that are vibrated in the gap direction of the developing area.

11 is a front view of FIG. 10 viewed from the right side.

FIG. 12 is a partial side view of the developing device showing another example of the linear control electrode which is vibrated in the gap direction of the developing area.

FIG. 13 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 carrier 2 developing device frame 3 developer reservoir 4 developer carrier 5 stirring means 6 stirring supply means 7 plate-like elastic body 8 control electrode 9 tension spring 10 abutting roller 12 cleaning blade

Claims (11)

[Claims] 1. A developer layer mainly composed of toner particles that does not rub against the surface of the image carrier is formed on the surface of the developer carrier, and the developer is caused to fly under an oscillating electric field in the developing region so that the surface of the image carrier is quiet. In a developing device for adhering to an electric image, the developer passes through the contact portion of a plate-like elastic body provided so that both ends of the developer layer are fixed and the middle is brought into contact with the developer transport body surface. The developing device is characterized in that 2. The developing device according to claim 1, wherein the plate-shaped elastic body is brought into contact with the developer carrier by a curved surface which is convex. 3. The plate-like elastic body satisfies a condition of 1.1t <γ <7t, where a rubber hardness is 50 to 80 °, a thickness is tmm, and a radius of curvature of a contact portion in a state of being separated from a developer transport body is γmm. The developing device according to claim 2. 4. The radius of curvature of the contact portion of the plate-like elastic body in a state of being separated from the developer transport body is large at the central portion in the device width direction and small at both end sides. Development device. 5. A layer of a developer containing toner particles that do not rub against the surface of the image carrier is formed on the surface of the developer carrier, and the developer is caused to fly under an oscillating electric field in the developing region so that the surface of the image carrier is quiet. In a developing device for adhering to an electric image, the developer carrier in the developing area is electrically insulated from the surface of the developer carrier on the downstream side within a range of 1 to 15 ° from the position closest to the image carrier. A developing device provided with a linear control electrode that is in contact with and vibrates by rotation of a developer transport body. 6. The linear control electrode, the surface of which is covered with an insulating material, wherein d is 0.1 g or more and 0.5 g or less, where d is an outer diameter of the linear control electrode and g is a minimum gap of a developing area. Development device. 7. The linear control electrode is provided by fixing both ends of the linear control electrode to both side walls of the device that rotatably supports the developer transport body via tension springs. Developing device. 8. A surface of the developer carrying body is formed with a layer of a developer mainly composed of toner particles which does not rub against the surface of the image carrying body, and the developer is caused to fly under an oscillating electric field in the developing region so that the surface of the image carrying body is kept stationary. In a developing device for adhering to an electric image, a linear control electrode is provided in the developing area so that it can vibrate in a gap direction of the developing area from a position where the linear carrier electrode abuts the surface of the developer carrier in an electrically insulated state and does not contact the surface of the image carrier A developing device characterized by the above. 9. The developing device according to claim 8, wherein one of the surface of the linear control electrode or the surface of the developer carrying carrier is covered with an insulating surface layer. 10. The developing device according to claim 8, wherein the vibration of the linear control electrode is given by the action of an oscillating electric field in the developing area. 11. The center of the linear control electrode is at a position separated by 0.1 g or more and 0.5 g or less from the surface of the developer transport body at a position where the minimum gap of the developing area is g in a state where the linear control electrode is not affected by an electric field. 11. The developing device according to claim 10, wherein the developing device is stretched so as not to contact the surface of the developer transport body.