JP2004093700A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which uniformly polishes the surface of an image carrier even of a wide machine, thereby removing soiling substances, and forms an image of high image quality over the lifetime of the image carrier. <P>SOLUTION: In a cleaning unit 12, a first blade (2) and a second blade (3) are disposed upstream and downstream, respectively, in the direction of the rotation of a photoreceptor (1), and a polishing agent (4) is held between the first blade (2) and the second blade (3). Preferably, the polishing agent (4) is in the range of 10 to 200 μm in particle diameter distribution. The first blade (2) and the second blade (3) may be structured so as to swing longitudinally. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a printer, and a plotter, and more particularly, to a wide-area machine capable of performing copying, printing, and plotting on a wide-width transfer paper or a multifunction machine thereof. It is.
[0002]
[Prior art]
As a general image forming process, an electrophotographic image forming apparatus forms an electrostatic latent image by irradiating light onto a uniformly charged image carrier surface, and attaches toner to the electrostatic latent image. The toner image is transferred to transfer paper, the transfer residual toner remaining on the image carrier remaining after the transfer is removed by a cleaning unit, and then the charge on the image carrier surface is removed. By repeating the above, large-volume, large-volume copying is possible.
By repeatedly performing image formation over a long period of time in this manner, the surface of the image carrier has nitrogen oxides generated by corona discharge, ozone, fine particles of toner remaining after transfer, toner components, or paper powder of transfer paper. The surface is contaminated by substances that cannot be removed by the cleaning means. As a result, a situation occurs that greatly affects the image quality when the image is blurred or the image flow occurs.
[0003]
One of the means for removing these substances contaminating the image carrier is a method of polishing an organic polymer resin portion on the surface of the image carrier. For example, a method in which an abrasive is constantly supplied to a toner accumulating portion as disclosed in Japanese Patent Application Laid-Open No. 8-194419, and a method in which an abrasive is rubbed on the surface of an image carrier with a roller as disclosed in Japanese Patent Application Laid-Open No. 2000-27626 are known. can give. One of the requirements for removing contaminants on the image carrier by polishing is to uniformly polish the surface of the image carrier. This is because the non-uniform polishing causes the charging performance to not be sufficiently exhibited during the required life of the image carrier, or causes uneven writing even when an electrostatic latent image is formed. Will come.
[0004]
However, especially in a wide-width machine capable of copying on transfer paper of A2 size (= paper width of 420 mm) or more, the position of the image forming process is determined from the layout aimed at miniaturizing the apparatus. FIG. 3 is a schematic diagram showing a layout of a conventional wide-width machine. Since the cleaning means (17) is large, it is provided above the image carrier (1). Therefore, the transfer paper is conveyed in the vertical direction as shown in the figure. However, since the roll paper is used in the wide-width machine for downsizing the apparatus, there is a problem that the transfer paper is curled and is difficult to be conveyed.
In addition, when viewed from the part processing surface, the wide width easily causes deflection. With the configuration as disclosed in Japanese Patent Application Laid-Open No. 2000-276026, it is very difficult to apply a roller of 500 mm or more to the image carrier uniformly, and it is difficult to increase the cost. .
[0005]
[Problems to be solved by the invention]
The present invention can solve these problems, can reduce the cost and diversify the layout in the image forming apparatus, and can even remove the contaminants by polishing the surface of the image carrier uniformly even in a wide-width machine. It is another object of the present invention to provide an image forming apparatus that forms a high-quality image over the life of an image carrier.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention according to claim 1 includes an image carrier, a charging unit for charging a surface of the image carrier, a writing unit for writing a latent image on the charged image carrier surface, An electrophotographic image forming apparatus comprising: developing means for developing an image; transfer means for transferring the developed toner image on the image carrier to transfer paper; and cleaning means for cleaning the surface of the image carrier after the transfer. In the image forming apparatus for a wide-width machine corresponding to a transfer sheet having a sheet width of 420 mm or more, the cleaning unit has two cleaning blades.
According to a second aspect of the present invention, in the cleaning unit, among the cleaning blades, a blade installed upstream in the rotation direction of the image carrier is a first blade, and a blade installed downstream is a second blade. The image forming apparatus according to claim 1, wherein abrasive particles are carried between the first blade and the second blade.
According to a third aspect of the present invention, there is provided the image forming apparatus according to the first or second aspect, wherein a particle size distribution of the abrasive particles is in a range of 10 to 200 μm.
According to a fourth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to third aspects, wherein the first blade and / or the second blade swings in a longitudinal direction.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a layout diagram around an image forming unit according to the image forming apparatus of the present invention. The image forming apparatus of the present invention is a wide-width machine capable of copying on transfer paper having a paper width of 420 mm or more.
The photoreceptor (1) as an image carrier rotates in the direction of the arrow in the figure, and the image forming process is repeated in the order of charging, writing, developing, transferring, cleaning, and discharging. Note that the image forming apparatus of the present invention has a small cleaning means, so that not only the layout of FIG. 1 but also various layouts are possible.
The photoreceptor 1 preferably has a drum shape. The material is preferably one having high surface hardness and excellent durability, and an organic photoreceptor in which filler particles are dispersed in a surface layer and an amorphous silicon-based photoreceptor can be suitably used.
The developer used in the developing unit 9 may be a wet type developer or a dry type developer.
Two cleaning blades are installed in a cleaning unit (12) as cleaning means.
[0008]
FIG. 2 is an enlarged view showing the area around the cleaning blade in FIG. The cleaning blade includes a first blade (2) and a second blade (3). The first blade (2) is installed on the upstream side in the rotation direction of the photoconductor (1), and the second blade (3) is installed on the downstream side. Are located. An abrasive (4) is carried between the first blade (2) and the second blade (3).
The first blade (2) and the second blade (3) are made of a material such as a metal, a resin, and a rubber, and a rubber such as a fluorine rubber, a silicone rubber, a butyl rubber, a butadiene rubber, an isoprene rubber, and a urethane rubber is preferably used. Of these, urethane rubber is particularly preferred, and foamed polyurethane rubber is more preferred.
The direction in which the first blade (2) and the second blade (3) are in contact with the photoreceptor (1) is not limited to the drawing, and may be a counter system or a trailing system.
[0009]
The first role of the first blade (2) is, firstly, to remove contaminants such as untransferred toner on the photoconductor (1) by the edge of the first blade (2). The chipped toner is transported to a predetermined position by the toner transport coil (13) and is processed as waste toner. Due to the role of the first blade (2), most of the transfer residual toner is removed from the photoconductor (1). Second, it functions to prevent the abrasive (4) between the first blade (2) and the second blade (3) from dropping onto the toner conveying coil (13). That is, the abrasive (4) is carried by the first blade (2). This makes it possible to always hold the abrasive (4) between the first blade (2) and the second blade (3).
The first role of the second blade (4) is to prevent the abrasive (4) from flowing out of the cleaning unit. Second, contaminants such as untransferred toner remaining on the photoreceptor (1), which could not be scraped off by the first blade (2), are also collected. This makes it possible to efficiently remove contaminants remaining on the photoconductor (1).
[0010]
The abrasive (4) is composed of known particles having abrasiveness, but silica and alumina can be suitably used, and each may be used alone or may be mixed.
The abrasive (4) is characterized in that the particle size distribution is in the range of 10 to 200 μm. When the particle diameter is smaller than 10 μm, the particle tends to slip through the gap between the cleaning blades. In particular, when the particle diameter is about 3 μm, the particles almost pass through, and dropping from the first blade (2) or flowing out from the second blade (3) occurs. If it exceeds 200 μm, the surface of the photoconductor (1) will be damaged.
By using the abrasive (4), the surface of the photoreceptor (1) can be uniformly polished, and the disadvantage in layout in a miniaturized image forming apparatus can be eliminated. Further, the cost can be reduced by using particles that can be easily processed.
[0011]
Further, the first blade (2) and / or the second blade (3) may be configured to swing in the longitudinal direction. Thereby, even if the dispersion of the polishing agent (4) is somewhat uneven, this can be compensated for, and the film removal of the photoconductor 1 can be made uniform. Further, in order to make the film shaving of the photoreceptor (1) more uniform, it is preferable to swing the first blade (2) and the second blade (3) in different phases.
[0012]
【The invention's effect】
As described above, according to the present invention, various layouts are possible with a low-cost configuration, and even if a wide-width machine is used, the photoconductor surface can be uniformly polished to remove contaminants. It is possible to provide an image forming apparatus that forms a high-quality image.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a layout around an image forming unit according to an image forming apparatus of the present invention.
FIG. 2 is an enlarged view showing the vicinity of a cleaning blade.
FIG. 3 is a diagram illustrating a configuration of an image forming apparatus of a conventional wide-width machine.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 photoconductor 2 first blade 3 second blade 4 abrasive 5 discharging lamp 6 charging unit 7 writing unit 9 developing unit 10 transfer / separation unit 12 cleaning unit 13 toner transfer coil

Claims (4)

Image carrier, charging means for charging the image carrier surface, writing means for writing a latent image on the charged image carrier surface, developing means for developing the latent image, and the developed toner image on the image carrier An electrophotographic image forming apparatus including a transfer unit that transfers the image onto a transfer sheet and a cleaning unit that cleans the surface of the image carrier after the transfer. In the device,
The image forming apparatus, wherein the cleaning unit has two cleaning blades. The cleaning means, among the cleaning blades, a blade installed on the upstream side in the image carrier rotation direction as a first blade, a blade installed on the downstream side as a second blade,
The image forming apparatus according to claim 1, wherein abrasive particles are carried between the first blade and the second blade. The image forming apparatus according to claim 1, wherein a particle size distribution of the abrasive particles is in a range of 10 to 200 μm. The image forming apparatus according to claim 1, wherein the first blade and / or the second blade swings in a longitudinal direction.

Images