JPH0365901A - Light illumination type destaticizer - Google Patents

Abstract

PURPOSE:To inexpensively increase a light quantity while a Fresnel lens is held used by narrowing the irradiation width of the direction orthogonal with the arranging direction of light emitting means by the single bodies of the Fresnel lens with respect to the irradiation width in the arranging direction. CONSTITUTION:The irradiation width of the direction Y-Y' orthogonal with the arranging direction X-X' of the light emitting means by the single bodies of the Fresnel lens is narrowed with respect to the irradiation width of the arranging direction X-X'. The light condensability is enhanced only in the direction Y-Y' orthogonal with the arranging direction X-X' of the light emitting means 21 in this way, by which the destaticizability in a non-image region is improved. The use of the Fresnel lens 25 which can be relatively inexpensively produced is possible and is advantageous for the cost of production. Further, the destaticizer can be disposed in proximity to an image carrying medium by directing the one Fresnel surface of the Fresnel lens 25 to the light emitting means 21 side. The increased quantity of light by the proximate disposition is expected.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an illumination-type static eliminator that eliminates unnecessary charges on an image carrier in an image forming apparatus such as an electrophotographic copying machine or a printer.

(Prior Art) Conventionally, as an image forming apparatus equipped with this type of illumination type static eliminator, there is an image forming apparatus as shown in FIG. 8, for example. That is,
In an image forming apparatus that can obtain images of various sizes from the same document, such as a copying machine that has a variable magnification function, the size of the image carrier 101 arranged in the apparatus is constant, so the variable magnification function is When the image carrier 101
A non-image area B inevitably occurs in a part of the area. If development is carried out in this state, excessive toner will be consumed due to unnecessary charges in the non-image area B, resulting in inconveniences such as staining the inside of the apparatus or producing black streaks on the copy paper. Therefore, as an illumination-type static eliminator 102 for eliminating unnecessary charges on the image carrier 101, a plurality of light emitting elements 103 are arranged, and these are turned on as necessary to eliminate static electricity in the non-image area B. is being carried out. Light from the light emitting elements 103 is irradiated through Fresnel lenses 104 corresponding to each light emitting element 103.

(Problem to be Solved by the Invention) However, in the case of the above-mentioned conventional technology, high-intensity light is required to sharply eliminate static electricity at the boundary between the image area A and the non-image area B; There is a problem in that if the element 103 has a high light intensity, it will lead to an increase in price, which is not desirable.

Furthermore, when the illuminated static eliminator 102 is brought closer to the image carrier 101 to increase the amount of light, air flows due to the rotation of the image carrier 101 and the resulting minute vibrations, which causes floating toner and dust. etc., adhere to the surface of the Fresnel lens 104, resulting in a decrease in the amount of light. Alternatively, it becomes necessary to take dustproof measures.

In addition, when trying to increase the amount of light by increasing the light focusing ability of the lens, it is necessary to irradiate light uniformly in the direction in which the light emitting elements 103 are arranged so that there is no unevenness in the irradiation, so the light can only be focused in the direction perpendicular to the direction in which the light emitting elements 103 are arranged. I can't improve my sexuality. Therefore, in order to focus the light only in the direction perpendicular to the array direction without concentrating the light in the array direction, it is sufficient to use an anamorphic lens with different focal lengths in both directions. However, anamorphic lenses are not manufactured The disadvantage is that it is difficult and expensive.

The present invention has been made to solve the problems of the prior art described above, and its purpose is to provide an illuminated static eliminator that can increase the amount of light at low cost while using a Fresnel lens.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a plurality of light emitting means arranged in a straight line and a plurality of Fresnels arranged corresponding to each of these light emitting means. In an illuminated static eliminator that eliminates unnecessary charges on the image carrier by irradiating light from the light emitting means onto the image carrier through these Fresnel lenses, the direction in which the light emitting means is arranged by a single Fresnel lens is The irradiation width in the direction perpendicular to the irradiation width is narrower than the irradiation width in the arrangement direction.

Note that it is desirable that the Fresnel surface of the Fresnel lens faces the light emitting means side.

Further, it is effective that the Fresnel surface of the Fresnel lens has a blazed shape.

(Function) In the present invention having the above configuration, the irradiation width in the direction orthogonal to the light emitting means arrangement direction by the Fresnel lens alone is made narrower than the irradiation width in the arrangement direction. Light convergence can be improved only in orthogonal directions.

Note that by directing one Fresnel surface of the Fresnel lens toward the light emitting means, the other flat lens surface is directed toward the image carrier, making it difficult for floating toner and dust to adhere.

Moreover, by making the Fresnel surface of the Fresnel lens into a blazed type, it is possible to irradiate light with high intensity.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. FIG. 5 is a diagram showing a schematic configuration of an image forming apparatus to which an illuminated static eliminator according to an embodiment of the present invention is applied. An image of a document 1 is illuminated by a document lamp 2, and is imaged onto an image carrier 4 by an imaging optical system 3 consisting of a plurality of mirrors, lenses, and the like. The image carrier 4 is rotatably supported in the direction of the arrow a in the figure, and around the image carrier 4,
- A charger 5, a developer 6, a transfer charger 7, a cleaner 8, etc. are provided. The illuminated static eliminator 9 according to the present invention includes:
It is disposed around the image carrier 4 and between the negative charger 5 and the developer 6. In addition, in the figure, 10 is a transfer material such as paper. Further, a fixing device and the like for fixedly fixing the toner to the transfer material IO are arranged, but these are omitted for convenience of explanation.

This image forming apparatus forms an electrostatic latent image on the surface of an image carrier 4 that is uniformly charged by a charger 5 . Then, this electrostatic latent image is visualized by a developing device 6, and the visible image on the image carrier 4 is transferred to a transfer material 10 by a transfer charger 7, and a fixed image is formed in a fixing device.

Further, the image forming apparatus described above can obtain copies of different sizes from the same size original 1 by adjusting the position of the lens of the imaging optical system 3. Therefore, this apparatus is a so-called variable magnification type image forming apparatus. In addition,
The scaling may be performed stepwise or continuously.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An illuminated static eliminator according to the present invention will be described below with reference to FIGS. 1 to 4. In the illumination type static eliminator 9 shown in FIG. 1, the surface of the image carrier 4 is illuminated (static neutralized) in the following manner. In other words, LED as a light emitting means
The light beams emitted from the 21 light emitting chips 22 are blocked by the light shielding member 23 and irradiated only from the opening 24 in a rectangular shape. This emitted light flux is L by a Fresnel lens 25 whose discontinuous Fresnel surface has a blazed shape.
In the arrangement direction x-x' of the EDs 21, the spread angle θ1 is narrowed down. On the other hand, as shown in FIG. 2, in the direction Y-Y' perpendicular to the arrangement direction, the light is largely focused at a convergence angle θ and irradiated onto the image carrier 4. In addition, Fresnel lens 2
5 is arranged corresponding to each of the plurality of linearly arranged LEDs 21. In order to enable such luminous flux control, the aperture of the Fresnel lens 25 according to the present invention is set so that the aperture of the Fresnel lens 25 according to the present invention is adjusted in the direction in which the LEDs 21 are arranged, with respect to the direction Y-Y' perpendicular to the arrangement direction of the LEDs 21, as shown in FIG. x-x
' is long and formed into a flat shape. In addition, LED2
Since the side wall portion 26 of the light shielding member 23 is present between 1 and 1,
Light from one LED 21 does not leak to the Fresnel lens 25 corresponding to an adjacent LED 21. The light flux emitted from the LEDs 21 is shaped into a rectangular light flux by the light shielding member 23, and is further narrowed down by the Fresnel lens 25 to provide high illuminance in the direction Y-Y' perpendicular to the arrangement direction of the LEDs 21. and irradiates onto the image carrier 25. Therefore, one Fresnel lens 25
Only the light from the LED 21 corresponding to the lens is transmitted from the fourth
With the shape shown in the figure, since the radiation is concentrated in the irradiation area 31, the boundary between the non-image area B and the image area A can be made sharp, and the non-image area B can be illuminated with high illuminance. Note that, in consideration of the arrangement error of the LEDs 21, it is desirable that the light beams between adjacent LEDs 21 have an overlapping portion on the image carrier 4. Therefore, it is effective to set the irradiation areas 31 so that they overlap with each other.

Further, in the above embodiment, the present invention has been described in detail by exemplifying the case where static electricity is removed from a non-image area caused by the reduction magnification, but the present invention is not limited to this. For example, there is an image forming apparatus that performs an editing function such as erasing an arbitrary part of a document 1 and inserting another document (including a different color).

Even in such an editing function, it is necessary to erase unnecessary charges from any region of the electrostatic latent image normally formed on the image carrier 4. Therefore, the illumination type static eliminator 9 of the present invention can irradiate this region with light to eliminate unnecessary charges.

In this case, any partial image on the image carrier 4 can be erased by partially emitting light from the linearly arranged LEDs 21 in accordance with the charge removal area and controlling the light emission timing.

FIG. 6 is a diagram showing an illuminated static eliminator according to a second embodiment of the present invention. In the above embodiment, the Fresnel surface was directed toward the image carrier 4, but in this embodiment, the Fresnel surface was directed toward the LED 21 as shown in the figure. In this case, the pitch of the annular zones forming the Fresnel surface of the Fresnel lens 25 is smaller than in the above embodiment, which is disadvantageous in terms of manufacturing cost, but a flat lens instead of a Fresnel surface is formed on the image carrier 4 side. Since the surface is oriented, floating toner and dust are less likely to adhere to the lens, preventing a decrease in light intensity. Therefore, it is possible to bring the static eliminator main body closer to the image carrier, which is effective for downsizing and also leads to an increase in the amount of light.

FIG. 7 shows an illuminated static eliminator according to a third embodiment of the present invention. In the above embodiment, the Fresnel lenses 25 were used in an array, but in this embodiment, the Fresnel lenses 25 are used as a single lens, and a light shielding section 41 is provided between each lens to completely cut out leakage light from adjacent light sources. It is something. With this configuration, the boundary between the image area A and the non-image area B can be clearly separated, and a high-quality image can be obtained.

(Effects of the Invention) The present invention has the above configuration and operation, and by making the irradiation width of the Fresnel lens alone in the direction orthogonal to the light emitting means arrangement direction narrower than the irradiation width in the arrangement direction, It is possible to improve the light gathering performance only in the direction perpendicular to the arrangement direction of the light emitting means, and it is possible to improve the static elimination performance in the non-image area. Further, a Fresnel lens, which can be manufactured relatively cheaply compared to an anamorphic lens, can be used, which is advantageous in terms of manufacturing cost.

By pointing one Fresnel surface of the Fresnel lens toward the light emitting means, the other flat lens surface faces the image carrier, making it difficult for floating toner and dust to adhere, which is advantageous in terms of dust prevention. . In addition, since it is less likely to get dirty, it becomes possible to arrange the static eliminator in close proximity to the image carrier, and it is possible to increase the amount of light due to the close arrangement.

Moreover, by making the Fresnel surface of the Fresnel lens into a blazed type, it is possible to irradiate light with high intensity.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a configuration diagram showing an illuminated static eliminator according to an embodiment of the present invention, and FIG. 3 is a diagram showing the aperture shape of the Fresnel lens according to the present invention, FIG. 4 is a diagram illustrating the irradiation area according to the present invention, and FIG. 5 is a diagram showing an image forming apparatus to which an illuminated static eliminator according to an embodiment of the present invention is applied. FIG. 6 is a diagram showing an illuminated static eliminator according to a second embodiment of the present invention,
FIG. 7 is a diagram showing an illumination type static eliminator according to a third embodiment of the present invention, and FIG. 8 is a diagram showing a conventional illumination type static eliminator. Explanation of symbols 4...Image carrier 21...LED (light emitting means) 25...Fresnel lens x-x'...LED arrangement direction Y-Y'...Direction orthogonal to the LED arrangement direction Figure 1

Claims (3)

[Claims] (1) A device comprising a plurality of linearly arranged light emitting means and a plurality of Fresnel lenses arranged corresponding to each of these light emitting means, and carrying light from the light emitting means through these Fresnel lenses to carry an image. In an illumination-type static eliminator that eliminates unnecessary charges on an image carrier by irradiating a body with light, the irradiation width in a direction perpendicular to the light emitting means arrangement direction by the Fresnel lens alone is narrower than the irradiation width in the arrangement direction. An illuminated static eliminator characterized by: (2) The illuminated static eliminator according to claim 1, wherein the Fresnel surface of the Fresnel lens faces the light emitting means. (3) The illuminated static eliminator according to claim 1, wherein the Fresnel surface of the Fresnel lens has a blazed shape.