JP2853373B2 - One-component developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device which is used in an image forming apparatus such as an electrophotographic copying machine or a printer, and which makes a developer adhere to an electrostatic latent image for visualization. The present invention relates to a one-component developing device that flies a one-component developer within an oscillating electric field generated between a body and a developer carrier to develop an electrostatic latent image.

[0002]

2. Description of the Related Art Conventionally, as a developing device for visualizing an electrostatic latent image by using a one-component developer, a developing device has been provided opposite to an electrostatic latent image holding member. 2. Description of the Related Art There has been known a developer provided with a developer regulating member and a developer supply section around a body. In such a developing device, the developer stored in a hopper or the like is supplied from a developer supply unit to a developer carrier. The developer carrier can transport the developer adhered to the surface. Further, the developer regulating member is provided so as to come into contact with the developer carrier at a predetermined pressure, and the developer adhering to the surface of the developer carrier is regulated by this to form a uniform thin layer. A desired charge is provided. Thereafter, the developer is sent to a position facing the electrostatic latent image holding member, and the developer flies to the electrostatic latent image holding member due to an oscillating electric field generated between the electrostatic latent image holding member and the developer holding member. Develop the latent image.

[0003] In the case of performing such development, when reproducing an original having a low density or a character original, a large amount of developer is not required at a time, so that uniform development is performed and a good visible image can be obtained. However, when attempting to reproduce an image having a very high density and including a solid black portion having a large area, the consumption of the developer becomes large at a time, so the supply of the developer becomes insufficient, and an image having a uniform density is obtained. May not be obtained.

To solve such a problem, a developing device as shown in FIG. 9 has been proposed. The developing device includes a uniformizing member 104 that rotates while being pressed against the developer carrier 101 in order to uniformly supply a large amount of the developer to the developer carrier 101, and the developer that moves in the axial direction of the developer carrier 101. And developer transport members 110 and 111 that constantly transport the developer in the developer accommodating chamber so that the amount of the developer in the developer storage chamber is kept constant. In this figure, reference numeral 102 denotes an electrostatic latent image holder,
Reference numeral 103 denotes a developer regulating member. In such a developing device, the developer is strongly rubbed against the developer carrying member 101 by the uniformizing member 104, an appropriate charge is applied, and a bias applied between the DC power supply 109 and the developer carrying member 101 is applied. A large amount of developer is also supplied uniformly by the voltage.

[0005]

However, in the one-component developing apparatus constructed as described above, the uniformizing member 104 is not provided.
Is pressed against the developer carrying member 101 at a contact pressure at which the contact depth becomes about 1 mm, and increases the torque of the developer carrying member driving motor. Further, since a stress is applied to the developer, a long-term use causes a change in the characteristics of the developer, resulting in a decrease in the amount of charge of the developer, a reduction in image quality, and contamination of the apparatus due to scattering of the developer. . Further, the developer transport members 110 and 111 are required, and there is a problem that the apparatus becomes complicated and large, and the manufacturing cost increases.

On the other hand, a means for uniformly supplying a large amount of developer by making the member for supplying the developer to the developer carrier non-contact with the developer carrier is also conceivable (Japanese Patent Application No. 2-218594).
However, since the member for supplying the developer is not in contact, the removal of the residual developer not consumed in the previous development from the developer carrier becomes insufficient, and the image quality is reduced. This is because, for example, an image history remains in the developer layer on the developer carrier, and a so-called ghost image in which the development density of a portion corresponding to the image in the previous development is increased, or the development is performed by performing development for a long time. A thin layer of fine developer that is extremely difficult to peel off is formed on the developer carrier (filming), and the developing performance is deteriorated. For example, the thin layer formed on the developer carrying member becomes non-uniform, and density unevenness occurs in an image.

The present invention has been made in view of the above-mentioned circumstances, and an image including a solid black portion having a large area can be reproduced at a uniform density, and an image defect such as a ghost image does not occur. It is an object of the present invention to provide a component developing device that is small and has a low manufacturing cost.

[0008]

In order to solve the above-mentioned problems, the present invention provides a method for forming a thin layer of a developer on a surface of a developer carrying member arranged in close proximity to an electrostatic latent image holding member, In a one-component developing apparatus for visualizing an electrostatic latent image on an electrostatic latent image holding member by flying a developer on a surface of the developer holding member at a position close to the electrostatic latent image holding member and the developer holding member, A cylindrical member having a plurality of apertures on a peripheral surface thereof, and peeling of a thin layer of the developer in contact with a surface of the developer carrier at a portion other than the apertures on the peripheral surface of the cylindrical member. And a stirring / supplying member rotatably supported around the axis of the cylindrical member at a position close to the surface of the developer carrying member.

The peeling member may be attached to the peripheral surface of the cylindrical body, and may be a block-shaped soft elastic body having one surface in contact with the developer carrier, or may be made of a material having the same triboelectric charging polarity as the developer. It is also possible to use a brush in which a number of wires are radially provided. The material forming the peeling member desirably has an electric resistance of 10 ² to 10 ¹⁰ Ωcm. on the other hand,
It is desirable that the opening ratio with respect to the peripheral area of the cylindrical body is in the range of 20 to 70%.

[0010]

In the one-component developing apparatus constructed as described above, the stirring / supplying member is provided with a cylindrical member having a plurality of apertures on its peripheral surface, and is rotated. The developer is agitated inside and is conveyed in the axial direction. Further, the developer is released from the opening by centrifugal force due to rotation, and a sufficient amount of the developer is supplied so as to sprinkle the surface of the developer carrier. In addition, since the peripheral surface of the cylindrical member has a peeling member that comes into contact with the surface of the developer carrier, the thin layer of the developer formed in the previous developing step does not contribute to the development and does not contribute to the development. What remains on the body is peeled off, and new developer is supplied by the action of the tubular member. As a result, the image history is deleted. At this time, the peeling member only needs to maintain a contact area and a contact pressure enough to peel the thin layer of the developer remaining on the surface of the developer carrier, and the amount of increase in the driving torque of the developer carrier is small.

As described above, the functions of stirring and transporting the developer, supplying the developer to the developer carrier, and removing the developer remaining on the surface of the developer carrier are performed only by the stirring / supplying member having the peeling member. This makes it unnecessary to separately provide a conveying member or a peeling member, and the image apparatus is reduced in size.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing the configuration of a one-component developing apparatus according to an embodiment of the present invention, and is a cross-sectional view of an image to be developed in a direction perpendicular to the width direction. The one-component developing device includes a cylindrical developer carrier 1 that rotates to face an electrostatic latent image carrier 2, a developer adhering amount on the developer carrier, and a thin layer of the developer. And a developer regulating member 3 for forming the developer, the developer is conveyed in the axial direction of the developer carrier while being stirred, the developer is supplied to the developer carrier 1, and the developer remaining on the surface of the developer carrier is supplied. A stirring / supplying member 4 for peeling off a thin layer of the developer formed in the developing step.

The developer carrier 1 has a surface on which a developer is attached and which can be transported by rotating the developer carrier. The developer carrier 1 can hold an electrostatic latent image 5 on the surface.
Is a development area A. The developer carrier 1 has a diameter of about 5 to 40 mm and preferably rotates at 100 to 300 times / minute. In the present embodiment, the developer carrier 1 has a diameter of 20 mm and rotates at 230 times / minute. In addition, after cutting a round bar or pipe of aluminum or stainless steel, a semiconductive layer such as phenol resin is provided on the circumferential surface, and mechanical polishing such as emery polishing is performed to reduce the surface roughness to Ra = 0.1 to It is about 1.0 μm. The phenolic resin has a volume resistance in the thickness direction of 10 ⁵ to 1
0 ¹² Ωm. The developer carrier is formed by cutting a round bar or pipe made of aluminum or stainless steel, and then machining the circumferential surface with sand blasting, liquid honing, emery polishing, or the like, or by performing chemical corrosion to obtain Ra = What formed the unevenness of about 0.1-1.0 micrometers may be sufficient. Further, a DC weight AC voltage is applied to the developer carrier 1 from a developing bias power supply 8, and the developer carrier 1 has a charge due to an electric field formed in a development area A which is a position close to the electrostatic latent image carrier 2. The developer adheres to the electrostatic latent image.

The developer regulating member 3 has a thickness of 0.03-0.
A silicon spring or EPDM rubber is vulcanized and bonded to a stainless steel leaf spring 3a of about 3 mm, and is brought into contact with the developer carrier 1 at a contact pressure of about 20 to 200 g / cm. As a result, the developer is formed into a thin layer having a thickness of about 5 to 30 μm, and is provided with a charge of about 2 to 20 μC / g.

The stirring / supplying member 4 is supported in the vicinity of the developer carrier 1 in a developer stirring chamber 6 provided at a position facing the developer carrier 1, and rotates in the same direction as the developer carrier 1. I do. It is desirable that the stirring and supply member 4 be used by providing a plurality of openings by cutting a cylindrical member of aluminum or stainless steel having a diameter of about 6 mm to 30 mm.
In this embodiment, an aluminum cylindrical member 4a having an outer diameter of 17 mm and an inner diameter of 10 mm is used. As shown in FIGS. 2 and 3, the opening 4b is formed in a substantially elliptical shape on the peripheral surface of the cylindrical member 4a, and is linearly arranged along the axial direction of the cylindrical member 4a. distance L ₂ between the axial length L ₁ and the opening and aperture of the is provided to be substantially equal. The rows of the apertures 4b are provided in four rows at positions distributed at 90 ° in the circumferential direction, and are arranged so as to be shifted by ピ ッ チ pitch from the positions of the apertures in the rows where the aperture positions are adjacent to each other. ing. Ratio of this hole to the total circumferential area (opening ratio)
Needs to be 20 to 70%, and preferably about 30 to 60%. In this embodiment, the opening ratio is almost 50%.
It has become.

As shown in FIGS. 2 and 3, the release member 4c is provided by attaching a block made of a synthetic resin foam to a portion of the aluminum cylindrical member 4a where no opening is provided, and is provided in the axial direction. Are arranged so that there is a fixed number of blocks on the peripheral surface at any position of the block. The height of the block-shaped separating member 4c is higher than the distance between the developer carrier 1 and the peripheral surface of the cylindrical member of the stirring / supplying member 4. A certain degree of deformation occurs. This peeling member 4c
The material is desirably a soft elastic body having an altitude of 40 ° or less. In addition to the foam, silicone rubber, urethane rubber,
Chloroprene rubber, fluorine rubber and the like can also be used. The rotation speed of the stirring / supplying member 4 is set to
The block is set in accordance with the circumferential arrangement of the blocks and the rotation speed of the developer carrier 1 so that the peeling member 4c in contact with the surface of the developer carrier can be wiped without a gap.

A bias voltage from a developer supply bias power supply 9 is applied between the stirring supply member 4 and the developer carrier 1, and sufficient developer is supplied from the stirring supply member 4 to the developer carrier 1. It is being supplied. If sufficient developer can be supplied without applying a bias voltage, it is not necessary to apply the bias voltage. When a bias voltage is applied, the volume resistance of the peeling member is set to about 10 ² to 10 ¹⁰ Ωcm to prevent leakage of the bias voltage when the resistance is small, and to reduce the effect due to charge accumulation when the resistance is large. Is to be prevented.

FIG. 4 is a view showing the developing device of this embodiment and a developer storage box 11 provided outside.
2, the developer in the developer storage box 11 is supplied from the side of the developing device to the inside 4d of the cylindrical member 4a of the stirring supply member 4.

As a developer used in the above-described one-component developing apparatus, a non-magnetic one-component developer, such as a pigment such as carbon or a metal-containing azo dye, is contained in various thermoplastic resins such as styrene resin and acrylic resin. It is possible to use a dispersion of a polarity control agent to a size of 5 to 20 μm by pulverization classification, to which a charge control agent is externally added. The charge control agent is
0.1μ of hydrophobized silica, alumina, titanium, etc.
m or less, but hydrophobic silica is most preferred.

Next, the operation of the above-described one-component developing apparatus will be described. Developer storage box 1 outside developing device
When the developer is introduced into the stirring / supplying member 4 from 1 through the developer conveying path 12, the stirring / supplying member 4 rotates and is gradually conveyed in the axial direction of the stirring / supplying member 4,
The developer is substantially uniformly distributed in the width direction of forming an image. At the same time, the rotation of the stirring supply member 4 discharges the developer into the developer stirring chamber 6 through a plurality of openings 4 b provided on the peripheral surface. The stirring / supplying member 4 and the developer carrier 1 are 0.2 to 0.2
The peripheral speed of the stirring / supplying member 4 is set to be about 1 to 3 times the peripheral speed of the developer carrying member 1 at an interval of about 3 mm.
The developer discharged from the inside by the rotation of the stirring supply member 4 flies toward the surface of the developer carrier 1, and a large amount of the developer adheres to the surface of the developer carrier 1. Further, a bias voltage is applied between the agitating and supplying member 4 and the developer carrier 1 to help supply a large amount of developer evenly.

The developer adhering to the surface of the developer carrier 1 is rubbed against the surface of the developer carrier 1 by the developer regulating member 3 to be thinned and charged. Further, as the developer carrier 1 rotates, the thinned developer is conveyed to the developing area A. Here, an oscillating electric field is generated between the developer carrier 1 and the electrostatic latent image holder 2 by the DC weight AC voltage applied to the developer carrier 1, and the charged developer flies, Electrostatic latent image 5 on electrostatic latent image carrier 2
To visualize.

The developer which has not contributed to the development in the developing area A is transported again into the developer stirring chamber 6 while adhering to the surface of the developer carrier 1, but the peeling member 4c of the rotating stirring supply member 4 is rotated. The surface of the developer carrier 1 is wiped to remove the developer once. Thereafter, the new developer discharged from the opening 4b of the stirring supply member 4 is supplied. As a result, the image history of the thin layer of the developer is erased, so that image defects such as so-called ghosts do not occur. Further, since a sufficient amount of the developer is supplied to the developer carrier 1, a wide area solid black is obtained. Images are also reproduced with high density. In order to confirm the temporal stability of the development process as described above, a long-term development test in which 50,000 developments were continuously performed using the one-component developing apparatus of the above embodiment was performed. No defects were observed and good results were obtained.

FIG. 5 is a view showing a modification of the stirring supply member used in the above embodiment. This stirring supply member 14
The apertures 14b provided in the rotating cylindrical member 14a are elongated in the axial direction, and the number of rows of apertures arranged in the circumferential direction is increased. In addition, the block-shaped peeling member 14c is disposed between rows of openings in the axial direction, and is provided continuously in the axial direction. With such a stirring and supplying member 14, even if a process of forming the opening 14b by punching in the production of the cylindrical member 14a is performed, the distortion error of the member is reduced, and the dimension from the rotation center to the surface of the cylindrical member 14a is reduced. The error (runout) can be reduced to about 0.2 mm or less, and the production cost can be reduced.
Further, a large number of peeling members 14c can be provided in the circumferential direction, so that the number of rotations of the stirring and supplying member 14 during driving can be reduced, and the stress applied to the developer and the driving force of the developer carrier 1 can be reduced.

FIG. 6 is a sectional view showing a one-component developing apparatus according to another embodiment of the present invention. In this one-component developing device,
As the stirring and supply member, a member having a brush-like peeling member 24c on the peripheral surface of a cylindrical member having an opening is used.
The individual wires of the brush-like peeling member 24c are cylindrical members 2
4a is implanted on the surface of the cylindrical member so as to be about 0.3 to 1.5 mm longer than the separation distance from the surface of the developer carrier 1 to the surface of the developer carrier 1. The tip of the member 24c wipes the surface of the developer carrier 1. It is desirable that the material for forming the brush has the same triboelectric charging property as the triboelectric charging property of the developer, and in this embodiment, it is assumed that the developer having a positive charging polarity is 490000 nylon fibers of 6 dur. Cylindrical member 24a at a density of / in ²
It is assumed to be planted radially from the surrounding surface.

In addition, a fluororesin fiber, rayon, acrylic fiber, polypropylene fiber, or the like can be used as the material of the brush-like peeling member 24c. When a bias voltage is applied to the stirring / supplying member 24, leakage of the bias voltage is prevented and the stirring / supplying member 24 is prevented from leaking.
When it is necessary to adjust the electric resistance value in order to prevent the electrification, a conductive region 25 made of, for example, carbon can be provided in the fiber as shown in FIG. 8 to adjust the specific resistance of the fiber.

The other parts of the one-component developing apparatus of this embodiment are the same as those of the first embodiment. As a result of developing the image including the solid black portion up to 50,000 times using such a one-component developing apparatus, an image having a sufficient density was obtained without occurrence of so-called ghost or the like. Further, in this embodiment, the contact area of the peeling member 24c with the surface of the developer carrier is small, the stress acting on the developer is reduced, the compression and aggregation of the developer is greatly reduced, and the driving of the developer carrier 1 is performed. The load on the force is also reduced.

[0027]

As described above, in the one-component developing apparatus of the present invention, the agitating / supplying member provided with the cylindrical member having a plurality of apertures on the peripheral surface and the peeling member in contact with the surface of the developer carrier. Rotates at a position close to the developer carrier, so that sufficient developer can be supplied to the surface of the developer carrier, and sufficient density can be obtained even when an image including a solid black portion is continuously developed. And a good image free of so-called ghosts can be obtained.

The stirring supply member stirs the developer.
Since it has both the function of transporting, the function of supplying the developer to the developer carrier, and the function of peeling off the thin layer of the developer remaining on the developer carrier, other transport means and peeling means It is not necessary to provide a developer, so that the developer can be downsized and the manufacturing cost can be reduced. Furthermore, the peeling member is only in contact with the developer carrier so that the thin layer of the developer that has not contributed to the previous development can be removed by wiping the surface of the developer carrier. And a stable image can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a configuration of a one-component developing device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a stirring and supplying member used in the one-component developing device of the embodiment.

FIG. 3 is a front view and a side view of a stirring and supplying member used in the one-component developing device of the embodiment.

FIG. 4 is an external view showing a state where a developer storage box is connected to the one-component developing device of the embodiment.

5A and 5B are a front view and a side view showing a modified example of the stirring supply member shown in FIG.

FIG. 6 is a schematic sectional view showing a configuration of a one-component developing device according to another embodiment of the present invention.

FIG. 7 is a perspective view showing a stirring and supplying member used in the one-component developing device of the embodiment shown in FIG.

8 is an enlarged view showing a cross section of a brush fiber which is a peeling member of the stirring / supplying member shown in FIG.

FIG. 9 is a schematic sectional view showing a configuration of a conventional one-component developing device.

[Description of sign]

 REFERENCE SIGNS LIST 1 developer carrier 2 electrostatic latent image holder 3 developer regulating member 4 stirring supply member 5 electrostatic latent image 6 developer stirring chamber 7 housing 8 development bias power supply 9 developer supply bias power supply 14 stirring supply member 24 Stirring supply member

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroshi Toyoda 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. In-house (56) References JP-A-63-304278 (JP, A) JP-A-4-100075 (JP, A) JP-A-3-154082 (JP, A) JP-A-3-164767 (JP, A) JP-A-58-4160 (JP, A) JP-A-64-66682 (JP, A) JP-A 62-35364 (JP, U) JP-A 63-135358 (JP, U) (58) (Int.Cl. ⁶ , DB name) G03G 15/08-15/095

Claims (1)

(57) [Claims] 1. A developer thin layer is formed on a surface of a developer carrier disposed in close proximity to an electrostatic latent image carrier, and the developer carrier is disposed in close proximity to the electrostatic latent image carrier. In a one-component developing device that visualizes an electrostatic latent image on an electrostatic latent image holding member by flying a developer on a surface of a developer carrier at a position, a cylindrical member having a plurality of apertures on a peripheral surface; A release member that comes into contact with the surface of the developer carrier to peel off a thin layer of developer at a portion other than the opening on the peripheral surface of the cylindrical member, and that is in close proximity to the surface of the developer carrier. A one-component developing device comprising: a stirring / supplying member rotatably supported around an axis of the cylindrical member at a position.