JP2004279527A - Development device and image-forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device for enabling proper development without fouling, by preventing fouling of a body device due to scattering of a developer or the like, and preventing scattering on an image, and to provide an image forming apparatus. <P>SOLUTION: The developing device is provided with an air current generating member 7, consisting of a rotating member which provides an oblique face on a blade shape, a screw shape or the end face of a rod material on the end of a developing roller 3, and sucks scattering toner from the whole axial region of the developing roller 3. In addition, by making the air current generating member 7 installed integrally on an end of the developing roller 3 since electric power and drive of the air current generating member 7 is not needed additionally, the number of components can be reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a facsimile, a printer, and a direct digital plate making machine using an electrophotographic method.
[0002]
[Prior art]
In a conventional electrophotographic developing device, a developer such as toner is stirred and charged in a developing container, and then the developer is conveyed onto a developing roller as a developer carrier. The developer guided on the developing roller is guided to a developing area, which is a re-proximity area between the developing roller and the latent image carrier, after the developer conveyance amount is regulated to be constant by the developer regulating member. Development is performed on the latent image carrier.
At that time, it is ideal that the developer on the developing roller is uniformly charged.However, some of the developer is not sufficiently charged. It jumps out and floats inside the machine, contaminating the main unit and the recording paper. Alternatively, the developer that has reached the end of the developing roller has poor circulation properties, and may eventually leak out of the container.
[0003]
As a method for preventing the scattering and leakage of the developer as described above, conventionally, the end of the developing roller and the vicinity of the developing area are covered with a case or a seal member as much as possible, and a suction unit and a developer collecting member are used. The methods used are known.
For example, in Patent Literature 1, a suction port and a discharge path are provided below a developer carrier, and scattered toner is sucked outside a developing device by a suction unit including a fan, a motor, and a control circuit, thereby preventing problems due to scattering of toner and the like. I am planning.
[0004]
In addition, as described in Patent Document 2, a carrier collecting member is provided near a developer carrier, and a carrier is collected using magnetic force and electric force. In some cases, a developer return passage is provided in a developing container, and a rotation recovery member is provided in the passage.
[Patent Document 1]
JP 2000-47483
[Patent Document 2]
JP-A-6-11970
[Patent Document 3]
JP-A-9-73230
[0006]
[Problems to be solved by the invention]
As described above, in the scattering prevention means in the developing device, when a large-scale suction device is provided as described in Patent Document 1, a large space is required for mounting a fan, a motor, a control circuit, and the like in the main body. However, the layout of the whole system is difficult, and it is not suitable for a machine aiming at miniaturization. In addition, power supply for the motor and the control circuit is necessary, which hinders energy saving. Further, as described in Patent Literature 2, the recovery method using a magnetic force or an electric force is a recovery method corresponding only to a device that receives a magnetic field or an electric field, and cannot recover a floating toner or the like that is insufficiently charged.
On the other hand, in the method of collecting and returning the developer as described in Patent Document 3, there is a possibility that foreign matter such as paper dust may be collected in the developing container, which may cause deterioration of image quality.
In view of the above problems, the present invention is directed to a developing device and an image forming apparatus which prevent contamination of a main body device due to scattering of a developer or the like and also prevent the scattering on an image, thereby enabling good development without contamination. It is an object to provide a device.
[0007]
[Means for Solving the Problems]
As described above, the present invention according to claim 1 is a developing device using a two-component developer, wherein the developing device includes an airflow generating member at an end of a developer carrier. Device.
According to a second aspect of the present invention, there is provided the developing device according to the first aspect, wherein the airflow generating member sucks from an entire area in the axial direction.
[0008]
According to a third aspect of the present invention, in the developing device according to the second aspect, the airflow generating member includes a fin at a shaft end portion of the developer carrier, and sucks the airflow from the entire area in the axial direction. Developing device.
According to a fourth aspect of the present invention, in the developing device according to the third aspect, the airflow generating member is a rotating member having one or more blades.
[0009]
According to a fifth aspect of the present invention, in the developing device according to the third aspect, the airflow generating member is a screw-shaped rotating member.
According to a sixth aspect of the present invention, in the developing device according to the third aspect, the airflow generating member is a rotating member having one or more inclined surfaces provided on an end surface of a bar. Device.
According to a seventh aspect of the present invention, in the developing device according to the third aspect, the developing device has one or more blades on an end surface of a developer carrier. is there.
[0010]
According to an eighth aspect of the present invention, in the developing device according to the third aspect, the developing device has a screw shape on an end surface of the developer carrier.
According to a ninth aspect of the present invention, in the developing device according to the third aspect, the developing device has one or more slopes on an end surface of the developer carrier. .
According to the present invention, an image is formed by exposing a latent image on an image carrier, writing the latent image on the image carrier, developing the latent image with a two-component developer, transferring the formed image to recording paper, and fixing the image. The image forming apparatus according to claim 1, wherein the image forming apparatus includes the developing device according to claim 1.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
First, the configuration of the developing device used in the present invention will be described.
FIG. 1 is a schematic view of a layout of a central section of the developing device.
In the developing case 1 accommodating the developing roller 3, the doctor blade 4, and the conveying screws 21 and 22, the developer is conveyed by the conveying screws 21 and 22 in opposite directions, and circulates in the case while being stirred. The developer conveyed by the screw 22 is pumped up by the developing roller 3, but is regulated by the doctor blade 4 to maintain a constant pumping amount and promote frictional charging of the developer.
When the developer pumped up on the developing roller 3 approaches the photosensitive drum 5 serving as a latent image carrier, toner flies onto the photosensitive drum 5 according to the latent image electric field and development is performed. Done. An entrance seal 6 for preventing toner scattering is provided between the developing roller 3 and the photosensitive drum 5.
[0012]
Next, the suction airflow generating member at the end of the developing roller according to the present invention will be described with reference to FIG. FIG. 2 is a perspective view of the developing device. There are a developing roller 3, a developing case 1 and an inlet seal 6, and an airflow generating member 7 is provided at an end of the developing roller 3. Further, an exhaust cover 8 is provided outside the airflow generating member 7, and a filter 9 is provided at an exhaust port. Therefore, the floating matter in the vicinity of the developing roller 3 is drawn into the suction airflow generated by the airflow generation member 7, enters the inside of the exhaust cover 8, and is captured and collected by the filter 9 at the exhaust port.
[0013]
FIG. 3 is a perspective view of the airflow generating member according to the fourth aspect. The airflow generating member is provided with a blade. When the blade rotates in the r direction, the blade takes in ambient gas (a in the figure) and flows in the axial direction (b in the figure) to generate an airflow.
The blade shape may be the shape shown in FIG. In this case, since the flow of the air current is generated along the axis as shown by the arrow, the action of preventing the accumulation of the developer at the end of the developing roller is particularly enhanced. The axis of the airflow generating member is D-shaped, that is, it rotates together with the developing roller. Therefore, it is not necessary to separately provide power supply and driving for the airflow generating member.
[0014]
FIG. 5 is a perspective view of the airflow generating member according to the fifth aspect. As shown in the figure, the airflow generating section has a screw shape. The processing method has been established for the screw as used for the developer conveying screw and the like, and is superior in mass productivity as compared with a screw having a blade as shown in FIG. Further, the developer accumulated on the end of the developing roller can be scraped and conveyed.
FIG. 6 is a perspective view of the airflow generating member according to the sixth aspect. An inclined portion is provided on the end surface of the rod to promote the airflow generation action, and the gas transfer efficiency is inferior to the shape using the blade or screw. However, the shape is the easiest to process and can achieve low cost.
[0015]
The present invention according to any one of claims 7 to 9 is such that the airflow generating member according to any one of claims 4 to 6 is integrally provided at an end of the developing roller. FIG. 7 shows this.
As an advantage of integrating the airflow generating member with the developing roller, one is to reduce the number of parts, and another is to prevent developer accumulation between the developing roller and the airflow generating member. Increasing the rigidity of the roller and suppressing deflection during rotation.
[0016]
【The invention's effect】
According to the present invention, the power and drive are not separately required, and the floating material is sucked and removed together with the suction airflow from the entire area of the developing roller in the axial direction around the developing roller, and the main body due to overflow or scattering of toner, paper dust, etc. It is possible to provide a developing apparatus and an image forming apparatus that can obtain high image quality without contamination of the apparatus and background contamination.
[Brief description of the drawings]
FIG. 1 is a schematic view of a layout of a central cross section of a developing device.
FIG. 2 is a perspective view of a developing device.
FIG. 3 is a perspective view of an airflow generating member having blades.
FIG. 4 is a perspective view of an airflow generating member having a D-shaped shaft.
FIG. 5 is a perspective view of an airflow generating member having a screw shape.
FIG. 6 is a perspective view of an airflow generating member provided with a slope on an end surface of a bar.
FIG. 7 is a conceptual diagram in which an airflow generating member is integrally provided at an end of a developing roller.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Developing cases 21 and 22 Conveyor screw 3 Developing roller 4 Doctor blade 5 Photoreceptor drum 6 Inlet seal 7 Air flow generating member 8 Exhaust cover 9 Filter

Claims (10)

In a developing device using a two-component developer,
The developing device includes an airflow generating member at an end of the developer carrier. The developing device according to claim 1,
The developing device according to claim 1, wherein the airflow generating member sucks the airflow from an entire region in the axial direction. The developing device according to claim 2,
The developing device according to claim 1, wherein the airflow generating member includes a fin at a shaft end portion of the developer carrier, and sucks the airflow from an entire area in the axial direction. The developing device according to claim 3,
The developing device according to claim 1, wherein the airflow generating member is a rotating member having one or more blades. The developing device according to claim 3,
The developing device, wherein the airflow generating member is a screw-shaped rotating member. The developing device according to claim 3,
The developing device is characterized in that the airflow generating member is a rotating member having one or more slopes provided on an end surface of a bar. The developing device according to claim 3,
The developing device is characterized in that the end surface of the developer carrier has one or more blade shapes. The developing device according to claim 3,
The developing device is characterized in that an end surface of a developer carrier has a screw shape. The developing device according to claim 3,
The developing device is characterized in that an end surface of the developer carrier has one or more slopes. An image forming apparatus that exposes an image carrier to write a latent image, develops the latent image with a two-component developer, forms an image, transfers the image to recording paper, fixes the image, and obtains an image.
An image forming apparatus comprising the developing device according to claim 1.

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